Clean up special characters in source files

Update Cargo.lock for v1.1.0
Bump version to 1.1.0 and update README
2026-02-19 22:11:04 +02:00 · 2026-02-19 22:06:21 +02:00 · 2026-02-19 22:02:21 +02:00 · 2026-02-19 22:00:51 +02:00 · 2026-02-19 22:00:43 +02:00 · 2026-02-19 21:42:30 +02:00
13 changed files with 890 additions and 534 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -23,8 +23,7 @@ nul
 data/

 # Editor directories and files
-.vscode/*
-!.vscode/extensions.json
+.vscode/
 .idea
 .DS_Store
 *.suo
@@ -32,3 +31,21 @@ data/
 *.njsproj
 *.sln
 *.sw?
+
+# AI/LLM tooling
+.claude/
+.cursor/
+.copilot/
+.codeium/
+.tabnine/
+.aider*
+.continue/
+
+# Trash
+trash/
+
+# Docs
+docs/
+
+# This file
+.gitignore
--- a/README.md
+++ b/README.md
@@ -8,7 +8,7 @@ Built for everyone. Owned by no one. Free as in freedom.

 <br>

-<img src="https://img.shields.io/badge/version-1.0.0-6B8AFF?style=flat-square&labelColor=282C33" alt="Version">
+<img src="https://img.shields.io/badge/version-1.1.0-6B8AFF?style=flat-square&labelColor=282C33" alt="Version">
 <img src="https://img.shields.io/badge/platform-Windows-6B8AFF?style=flat-square&labelColor=282C33" alt="Platform">
 <img src="https://img.shields.io/badge/Tauri-v2-6B8AFF?style=flat-square&labelColor=282C33" alt="Tauri">
 <img src="https://img.shields.io/badge/license-CC0_Public_Domain-6B8AFF?style=flat-square&labelColor=282C33" alt="License">
@@ -19,7 +19,7 @@ Built for everyone. Owned by no one. Free as in freedom.

 ## 📖 Overview

-Vesper renders your markdown with carefully tuned typography and a refined dark interface, giving you the ultimate reading experience. No installation, no AppData, no registry, no telemetry, no accounts, no subscriptions - just drop the exe and go.
+Vesper renders your markdown with carefully tuned typography and a refined interface, giving you the ultimate reading experience. Choose between dark and light themes, navigate entirely by keyboard, and enjoy full WCAG 2.2 AAA accessibility. No installation, no AppData, no registry, no telemetry, no accounts, no subscriptions - just drop the exe and go.

 Knowledge should be accessible to all. Vesper exists to make reading a pleasure, not a product.

@@ -42,7 +42,7 @@ Full CommonMark support via **markdown-it** with extensions:
 | 📄 HTML | Inline HTML passthrough |
 | ↵ Breaks | Newlines preserved as line breaks |

-**Premium dark-mode typography** tuned for long-form reading:
+**Premium typography** tuned for long-form reading:

 > - **Inter Variable** at 17px with 1.7 line-height
 > - ~65 character measure for optimal readability
@@ -80,9 +80,10 @@ Full CommonMark support via **markdown-it** with extensions:

 | Feature | Details |
 |:--|:--|
+| 🌗 Dark / Light Theme | Toggle in View menu, persisted across sessions |
 | 🖥️ Focus Mode | `F11` hides title bar and menu for immersive reading |
-| 🔎 Content Zoom | `Ctrl+Scroll` - 50% to 200% |
-| ↔️ Content Width | `Shift+Scroll` - 400px to 1200px |
+| 🔎 Content Zoom | `Ctrl+Scroll` or View menu spinner - 50% to 200% |
+| ↔️ Content Width | `Shift+Scroll` or View menu spinner - 400px to 1200px |
 | 🔲 UI Scale | 50%-200% via View menu spinner, persisted across sessions |
 | 🏀 Kinetic Scroll | Right-mouse drag with iOS-style rubber band overscroll |
 | 📜 Custom Scrollbars | Thin, auto-hiding, accent-colored on hover |
@@ -92,8 +93,9 @@ Full CommonMark support via **markdown-it** with extensions:

 ### 📂 File Handling

- Open via **File menu**, **`Ctrl+O`**, or **drag-and-drop** from Explorer
+- Open via **File menu**, **`Ctrl+O`**, **drag-and-drop**, or **double-click** from Explorer
 - Supports `.md` · `.markdown` · `.txt`
+- **Single instance** - opening a file when Vesper is already running forwards it to the existing window
 - Native Tauri drag-and-drop integration with real file system paths

 <br>
@@ -109,6 +111,26 @@ Full CommonMark support via **markdown-it** with extensions:

 <br>

+## ♿ Accessibility
+
+Vesper targets **WCAG 2.2 AAA** compliance across the entire interface.
+
+| Area | Details |
+|:--|:--|
+| 🏗️ Semantic HTML | `<header>`, `<nav>`, `<main>`, `<article>`, `<search>` landmarks; proper ARIA roles for menus, tabs, dialogs, and status regions |
+| ⌨️ Full Keyboard Navigation | Menu bar, tab bar, sidebar TOC, modals, and context menu all navigable with arrow keys, Home/End, Enter, Escape |
+| 🔗 Skip Link | "Skip to content" link as first focusable element for screen reader users |
+| 🎯 Focus Management | Visible `:focus-visible` outlines on all interactive elements; focus traps in modals with restore on close |
+| 🌗 High Contrast Themes | Dark and light themes both meet AAA contrast ratios (7:1+ for normal text) |
+| 🎞️ Reduced Motion | Respects `prefers-reduced-motion` OS setting - all animations disabled when active |
+| 📋 Active Heading Tracking | Current section highlighted in sidebar TOC via IntersectionObserver |
+| 🔲 Target Sizes | All interactive targets meet 24x24px minimum (WCAG 2.5.8) |
+| 📢 Status Messages | Search results counter uses `aria-live="polite"` for screen reader announcements |
+| 🎨 Non-Color Indicators | Active tabs marked with a bottom border accent; search highlights include underline in addition to background |
+| ↔️ Resizable Sidebar | Keyboard-accessible resize handle (`role="separator"`) with arrow key support |
+
+<br>
+
 ## ⌨️ Keyboard Shortcuts

 | Shortcut | Action |
@@ -119,7 +141,9 @@ Full CommonMark support via **markdown-it** with extensions:
 | `Ctrl+F` | 🔍 Toggle search |
 | `Ctrl+Shift+S` | 📋 Toggle sidebar |
 | `F11` | 🖥️ Toggle focus mode |
-| `Escape` | ← Close search / sidebar |
+| `Escape` | ← Close search / sidebar / context menu |
+| `Shift+F10` | 📋 Open context menu |
+| `Delete` | ✕ Close focused tab (when tab bar is focused) |
 | `Ctrl+Scroll` | 🔎 Zoom content in / out |
 | `Shift+Scroll` | ↔️ Adjust content width |

@@ -134,7 +158,7 @@ Full CommonMark support via **markdown-it** with extensions:

 ### Download

-Download the latest **`vesper.exe`** from the [Releases](https://github.com/yourusername/vesper/releases) page.
+Download the latest **`vesper.exe`** from the [Releases](https://git.lashman.live/lashman/vesper/releases) page.
 No installation required - Vesper is fully portable. No gatekeepers between you and your documents.

 ### Build from Source
@@ -144,7 +168,7 @@ Everyone has the right to inspect, modify, and rebuild the tools they use.
 > **Requires:** [Node.js](https://nodejs.org/) v18+ · [Rust](https://www.rust-lang.org/tools/install) stable · [Tauri v2 prerequisites](https://v2.tauri.app/start/prerequisites/)

 ```bash
-git clone https://github.com/yourusername/vesper.git
+git clone https://git.lashman.live/lashman/vesper.git
 cd vesper
 npm install
 ```
@@ -176,7 +200,7 @@ Built entirely on open-source foundations - no proprietary dependencies, no vend
 | 🖼️ | Icons | [Lucide React](https://lucide.dev/) |
 | 📜 | Scrollbars | [OverlayScrollbars](https://kingsora.github.io/OverlayScrollbars/) |

-**Tauri Plugins:** `dialog` · `fs` · `opener`
+**Tauri Plugins:** `dialog` · `fs` · `opener` · `single-instance`

 <br>

@@ -204,8 +228,8 @@ data/
 |:--|:--|
 | 📖 | **Content First** - all UI chrome can be hidden; the reader is the focus |
 | 🔤 | **Typography Matters** - Inter at 17px, 1.7 line-height, ~65 char measure |
-| 🌙 | **Dark by Default** - deep onyx base `#282C33` reduces eye strain |
-| ⌨️ | **Keyboard Driven** - every feature accessible via shortcuts |
+| 🌗 | **Dark & Light** - two high-contrast themes, both WCAG AAA compliant |
+| ⌨️ | **Keyboard Driven** - every feature accessible via shortcuts and arrow keys |
 | ✨ | **Minimalist Chrome** - the interface gets out of your way |
 | 🤝 | **No Extraction** - no ads, no tracking, no data harvesting, no paywalls |

--- a/package.json
+++ b/package.json
@@ -1 +1 @@
-{"name":"vesper","private":true,"version":"1.0.1","type":"module","scripts":{"dev":"vite","build":"tsc && vite build","preview":"vite preview","tauri":"tauri"},"dependencies":{"@fontsource-variable/inter":"^5.2.8","@fontsource-variable/jetbrains-mono":"^5.2.8","@tailwindcss/typography":"^0.5.19","@tailwindcss/vite":"^4.1.18","@tauri-apps/api":"^2","@tauri-apps/plugin-dialog":"^2.6.0","@tauri-apps/plugin-fs":"^2.4.5","@tauri-apps/plugin-opener":"^2","daisyui":"^5.5.18","framer-motion":"^12.34.0","highlight.js":"^11.11.1","lucide-react":"^0.564.0","markdown-it":"^14.1.1","markdown-it-mark":"^4.0.0","markdown-it-sub":"^2.0.0","markdown-it-sup":"^2.0.0","markdown-it-task-lists":"^2.1.1","overlayscrollbars":"^2.14.0","overlayscrollbars-react":"^0.5.6","react":"^19.1.0","react-dom":"^19.1.0","tailwindcss":"^4.1.18"},"devDependencies":{"@tauri-apps/cli":"^2","@types/markdown-it":"^14.1.2","@types/react":"^19.1.8","@types/react-dom":"^19.1.6","@vitejs/plugin-react":"^4.6.0","png-to-ico":"^3.0.1","puppeteer-core":"^24.37.3","sharp":"^0.34.5","typescript":"~5.8.3","vite":"^7.0.4"}}
+{"name":"vesper","private":true,"version":"1.1.0","type":"module","scripts":{"dev":"vite","build":"tsc && vite build","preview":"vite preview","tauri":"tauri"},"dependencies":{"@fontsource-variable/inter":"^5.2.8","@fontsource-variable/jetbrains-mono":"^5.2.8","@tailwindcss/typography":"^0.5.19","@tailwindcss/vite":"^4.1.18","@tauri-apps/api":"^2","@tauri-apps/plugin-dialog":"^2.6.0","@tauri-apps/plugin-fs":"^2.4.5","@tauri-apps/plugin-opener":"^2","daisyui":"^5.5.18","framer-motion":"^12.34.0","highlight.js":"^11.11.1","lucide-react":"^0.564.0","markdown-it":"^14.1.1","markdown-it-mark":"^4.0.0","markdown-it-sub":"^2.0.0","markdown-it-sup":"^2.0.0","markdown-it-task-lists":"^2.1.1","overlayscrollbars":"^2.14.0","overlayscrollbars-react":"^0.5.6","react":"^19.1.0","react-dom":"^19.1.0","tailwindcss":"^4.1.18"},"devDependencies":{"@tauri-apps/cli":"^2","@types/markdown-it":"^14.1.2","@types/react":"^19.1.8","@types/react-dom":"^19.1.6","@vitejs/plugin-react":"^4.6.0","png-to-ico":"^3.0.1","puppeteer-core":"^24.37.3","sharp":"^0.34.5","typescript":"~5.8.3","vite":"^7.0.4"}}
--- a/public/tauri.svg
+++ b/public/tauri.svg
@@ -1,6 +0,0 @@
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-<path d="M143.143 84C143.143 96.1503 133.293 106 121.143 106C108.992 106 99.1426 96.1503 99.1426 84C99.1426 71.8497 108.992 62 121.143 62C133.293 62 143.143 71.8497 143.143 84Z" fill="#FFC131"/>
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-</svg>
--- a/public/vite.svg
+++ b/public/vite.svg
@@ -1 +0,0 @@
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--- a/src-tauri/Cargo.lock
+++ b/src-tauri/Cargo.lock
@@ -3703,6 +3703,21 @@ dependencies = [
 "zbus",
 ]

+[[package]]
+name = "tauri-plugin-single-instance"
+version = "2.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dc61e4822b8f74d68278e09161d3e3fdd1b14b9eb781e24edccaabf10c420e8c"
+dependencies = [
+ "serde",
+ "serde_json",
+ "tauri",
+ "thiserror 2.0.18",
+ "tracing",
+ "windows-sys 0.60.2",
+ "zbus",
+]
+
 [[package]]
 name = "tauri-runtime"
 version = "2.10.0"
@@ -4281,7 +4296,7 @@ checksum = "0b928f33d975fc6ad9f86c8f283853ad26bdd5b10b7f1542aa2fa15e2289105a"

 [[package]]
 name = "vesper"
-version = "0.1.0"
+version = "1.1.0"
 dependencies = [
 "serde",
 "serde_json",
@@ -4290,6 +4305,7 @@ dependencies = [
 "tauri-plugin-dialog",
 "tauri-plugin-fs",
 "tauri-plugin-opener",
+ "tauri-plugin-single-instance",
 ]

 [[package]]
--- a/src-tauri/Cargo.toml
+++ b/src-tauri/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "vesper"
-version = "1.0.1"
+version = "1.1.0"
 description = "A beautiful markdown reader"
 authors = ["you"]
 edition = "2021"
@@ -22,3 +22,6 @@ tauri-plugin-fs = "2"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"

+[target.'cfg(not(any(target_os = "android", target_os = "ios")))'.dependencies]
+tauri-plugin-single-instance = "2"
+
--- a/src-tauri/src/lib.rs
+++ b/src-tauri/src/lib.rs
@@ -39,6 +39,31 @@ fn save_window_state(state: &WindowState) {
    }
 }

+#[derive(Serialize, Clone)]
+struct CliFile {
+    path: String,
+    content: String,
+}
+
+/// Try to read a markdown file from the given path string.
+fn read_md_file(file_arg: &str) -> Option<CliFile> {
+    let path = PathBuf::from(file_arg);
+    if !path.is_file() { return None; }
+    let ext = path.extension()?.to_str()?.to_lowercase();
+    if ext != "md" && ext != "markdown" && ext != "txt" { return None; }
+    let content = fs::read_to_string(&path).ok()?;
+    Some(CliFile {
+        path: path.to_string_lossy().to_string(),
+        content,
+    })
+}
+
+/// Returns the file path + content if the app was launched with a .md/.markdown/.txt argument.
+#[tauri::command]
+fn get_cli_file() -> Option<CliFile> {
+    env::args().nth(1).and_then(|a| read_md_file(&a))
+}
+
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
 pub fn run() {
    let data_dir = get_data_dir();
@@ -51,9 +76,23 @@ pub fn run() {
    );

    tauri::Builder::default()
+        .plugin(tauri_plugin_single_instance::init(|app, args, _cwd| {
+            // Second instance launched with a file - send it to the existing window
+            if let Some(file_arg) = args.get(1) {
+                if let Some(cli_file) = read_md_file(file_arg) {
+                    let _ = app.emit("open-file", cli_file);
+                }
+            }
+            // Focus the existing window
+            if let Some(window) = app.get_webview_window("main") {
+                let _ = window.unminimize();
+                let _ = window.set_focus();
+            }
+        }))
        .plugin(tauri_plugin_opener::init())
        .plugin(tauri_plugin_dialog::init())
        .plugin(tauri_plugin_fs::init())
+        .invoke_handler(tauri::generate_handler![get_cli_file])
        .setup(|app| {
            let state = load_window_state();
            let window = app.get_webview_window("main").unwrap();
@@ -64,35 +103,12 @@ pub fn run() {
                ));
            }
            if let (Some(w), Some(h)) = (state.width, state.height) {
-                let _ = window.set_size(tauri::Size::Physical(
-                    tauri::PhysicalSize::new(w, h),
-                ));
+                let _ = window.set_size(tauri::Size::Physical(tauri::PhysicalSize::new(w, h)));
            }
            if let Some(true) = state.maximized {
                let _ = window.maximize();
            }

-            // If launched with a file argument (e.g. double-clicking a .md file),
-            // emit the path to the frontend so it can open it as a tab.
-            let args: Vec<String> = env::args().collect();
-            if let Some(file_arg) = args.get(1) {
-                let path = PathBuf::from(file_arg);
-                if path.is_file() {
-                    if let Some(ext) = path.extension().and_then(|e| e.to_str()) {
-                        let ext_lower = ext.to_lowercase();
-                        if ext_lower == "md" || ext_lower == "markdown" || ext_lower == "txt" {
-                            let path_str = path.to_string_lossy().to_string();
-                            let win = window.clone();
-                            // Emit after a short delay so the frontend has time to set up listeners
-                            std::thread::spawn(move || {
-                                std::thread::sleep(std::time::Duration::from_millis(500));
-                                let _ = win.emit("open-file", path_str);
-                            });
-                        }
-                    }
-                }
-            }
-
            Ok(())
        })
        .on_window_event(|window, event| {
--- a/src-tauri/tauri.conf.json
+++ b/src-tauri/tauri.conf.json
@@ -1,7 +1,7 @@
 {
  "$schema": "https://schema.tauri.app/config/2",
  "productName": "Vesper",
-  "version": "1.0.1",
+  "version": "1.1.0",
  "identifier": "com.vesper.reader",
  "build": {
    "beforeDevCommand": "npm run dev",
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -1,12 +1,14 @@
 import { useState, useEffect, useLayoutEffect, useCallback, useRef, useMemo } from "react";
 import { open } from "@tauri-apps/plugin-dialog";
+import { openUrl } from "@tauri-apps/plugin-opener";
 import { readTextFile } from "@tauri-apps/plugin-fs";
 import { getCurrentWindow } from "@tauri-apps/api/window";
 import { getCurrentWebview } from "@tauri-apps/api/webview";
+import { invoke } from "@tauri-apps/api/core";
 import { listen } from "@tauri-apps/api/event";
 import MarkdownIt from "markdown-it";
 import hljs from "highlight.js";
-import { motion, AnimatePresence } from "framer-motion";
+import { motion, AnimatePresence, useReducedMotion } from "framer-motion";
 import TaskLists from "markdown-it-task-lists";
 import sup from "markdown-it-sup";
 import sub from "markdown-it-sub";
@@ -37,9 +39,8 @@ const md: MarkdownIt = new MarkdownIt({
 }).use(TaskLists).use(sup).use(sub).use(mark);

 const materialEase = [0.4, 0, 0.2, 1] as const;
-const smoothTransition = { duration: 0.2, ease: materialEase };

-// Saved selection range — set in mousedown (before browser clears it), read in contextmenu handler
+// Saved selection range - set in mousedown (before browser clears it), read in contextmenu handler
 let _savedSelectionRange: Range | null = null;

 // Reusable kinetic scroll + iOS overscroll setup for any scrollable area
@@ -239,6 +240,77 @@ function setupKineticScroll(
  };
 }

+function useFocusTrap(isOpen: boolean, containerRef: React.RefObject<HTMLElement | null>) {
+  const triggerRef = useRef<HTMLElement | null>(null);
+
+  useEffect(() => {
+    if (!isOpen) return;
+
+    // Save the element that had focus before the modal opened
+    triggerRef.current = document.activeElement as HTMLElement;
+
+    // Wait for AnimatePresence to render the modal
+    const raf = requestAnimationFrame(() => {
+      const container = containerRef.current;
+      if (!container) return;
+
+      const focusable = container.querySelectorAll<HTMLElement>(
+        'button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])'
+      );
+      if (focusable.length > 0) focusable[0].focus();
+    });
+
+    return () => {
+      cancelAnimationFrame(raf);
+      // Restore focus to trigger element when modal closes
+      triggerRef.current?.focus();
+      triggerRef.current = null;
+    };
+  }, [isOpen, containerRef]);
+
+  useEffect(() => {
+    if (!isOpen) return;
+
+    const container = containerRef.current;
+    if (!container) return;
+
+    const handleKeyDown = (e: KeyboardEvent) => {
+      if (e.key === 'Escape') {
+        e.preventDefault();
+        e.stopPropagation();
+        // The modal's own close handler will be called separately
+        return;
+      }
+
+      if (e.key !== 'Tab') return;
+
+      const focusable = container.querySelectorAll<HTMLElement>(
+        'button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])'
+      );
+      if (focusable.length === 0) return;
+
+      const first = focusable[0];
+      const last = focusable[focusable.length - 1];
+
+      if (e.shiftKey) {
+        if (document.activeElement === first) {
+          e.preventDefault();
+          last.focus();
+        }
+      } else {
+        if (document.activeElement === last) {
+          e.preventDefault();
+          first.focus();
+        }
+      }
+    };
+
+    // Use capture to intercept Tab before anything else
+    document.addEventListener('keydown', handleKeyDown, true);
+    return () => document.removeEventListener('keydown', handleKeyDown, true);
+  }, [isOpen, containerRef]);
+}
+
 function App() {
  const [tabs, setTabs] = useState<Tab[]>([]);
  const [activeTabId, setActiveTabId] = useState<string | null>(null);
@@ -251,9 +323,14 @@ function App() {
  const [currentMatchIndex, setCurrentMatchIndex] = useState(0);
  const [headings, setHeadings] = useState<Heading[]>([]);
  const [menuOpen, setMenuOpen] = useState<string | null>(null);
+  const [menuFocusIndex, setMenuFocusIndex] = useState(0);
+  const menuItems = ['file', 'view', 'help'] as const;
  const [showShortcutsModal, setShowShortcutsModal] = useState(false);
  const [showAboutModal, setShowAboutModal] = useState(false);
  const [zoom, setZoom] = useState(100);
+  const [theme, setTheme] = useState<'dark' | 'light'>(() => {
+    return (localStorage.getItem('vesper-theme') as 'dark' | 'light') || 'dark';
+  });
  const [uiZoom, setUiZoom] = useState(() => {
    const saved = localStorage.getItem('vesper-ui-zoom');
    return saved ? parseInt(saved, 10) : 100;
@@ -267,17 +344,33 @@ function App() {
  const [resizeStartState, setResizeStartState] = useState<{ startX: number; startWidth: number } | null>(null);
  const [contextMenu, setContextMenu] = useState<{ x: number; y: number; selectedText: string } | null>(null);
  const [selectionRects, setSelectionRects] = useState<{ left: number; top: number; width: number; height: number }[]>([]);
+  const [tabFocusIndex, setTabFocusIndex] = useState(0);
+  const [sidebarFocusIndex, setSidebarFocusIndex] = useState(0);
+  const [activeHeadingText, setActiveHeadingText] = useState<string | null>(null);

  const contentRef = useRef<HTMLDivElement>(null);
  const sidebarRef = useRef<HTMLDivElement>(null);
  const searchInputRef = useRef<HTMLInputElement>(null);
-  const menuItemRefs = useRef<{ [key: string]: HTMLDivElement | null }>({});
+  const menuItemRefs = useRef<{ [key: string]: HTMLButtonElement | null }>({});
  const kineticDragActiveRef = useRef(false);
  const contextMenuRef = useRef<HTMLDivElement>(null);
+  const contextMenuTriggerRef = useRef<Element | null>(null);
  const tabScrollRef = useRef<HTMLDivElement>(null);
+  const tabRefs = useRef<(HTMLDivElement | null)[]>([]);
+  const sidebarItemRefs = useRef<(HTMLButtonElement | null)[]>([]);
  const [tabScrollState, setTabScrollState] = useState({ canLeft: false, canRight: false });
  const tabsRef = useRef(tabs);
  tabsRef.current = tabs;
+  const shortcutsModalRef = useRef<HTMLDivElement>(null);
+  const aboutModalRef = useRef<HTMLDivElement>(null);
+
+  const prefersReducedMotion = useReducedMotion();
+  const smoothTransition = prefersReducedMotion
+    ? { duration: 0 }
+    : { duration: 0.2, ease: materialEase };
+
+  useFocusTrap(showShortcutsModal, shortcutsModalRef);
+  useFocusTrap(showAboutModal, aboutModalRef);

  const [appWindow, setAppWindow] = useState<ReturnType<typeof getCurrentWindow> | null>(null);
  const activeTab = tabs.find(t => t.id === activeTabId) || null;
@@ -324,6 +417,7 @@ function App() {
          }));
        }

+        contextMenuTriggerRef.current = document.activeElement;
        setContextMenu({ x, y, selectedText });
        setSelectionRects(rects);
      }
@@ -337,11 +431,39 @@ function App() {
    };
  }, [activeTab, uiZoom]);

+  // Open external links in default OS browser
+  useEffect(() => {
+    const handleLinkClick = (e: MouseEvent) => {
+      const anchor = (e.target as HTMLElement).closest('a[href]') as HTMLAnchorElement | null;
+      if (!anchor) return;
+      const href = anchor.getAttribute('href');
+      if (href && /^https?:\/\//.test(href)) {
+        e.preventDefault();
+        openUrl(href);
+      }
+    };
+    document.addEventListener('click', handleLinkClick);
+    return () => document.removeEventListener('click', handleLinkClick);
+  }, []);
+
  // Clear selection overlay when context menu closes
  useEffect(() => {
    if (!contextMenu) setSelectionRects(prev => prev.length > 0 ? [] : prev);
  }, [contextMenu]);

+  // Auto-focus first menuitem when context menu opens; restore focus on close
+  useEffect(() => {
+    if (contextMenu) {
+      requestAnimationFrame(() => {
+        const firstItem = contextMenuRef.current?.querySelector<HTMLElement>('[role="menuitem"]');
+        firstItem?.focus();
+      });
+    } else {
+      (contextMenuTriggerRef.current as HTMLElement)?.focus();
+      contextMenuTriggerRef.current = null;
+    }
+  }, [contextMenu]);
+
  // Clamp context menu within window bounds after render
  useLayoutEffect(() => {
    const menu = contextMenuRef.current;
@@ -378,7 +500,7 @@ function App() {
    setHeadings(parsed);
  }, []);

-  // Render markdown to HTML — memoized so it only re-runs when content changes
+  // Render markdown to HTML - memoized so it only re-runs when content changes
  const renderedHtml = useMemo(() => {
    if (!activeTab) return '';
    return md.render(activeTab.content);
@@ -477,6 +599,7 @@ function App() {
  }, [updateTabScrollState]);

  // Tauri native drag-and-drop (bypasses browser event interception)
+  const pendingDropPaths = useRef<Set<string>>(new Set());
  useEffect(() => {
    let unlisten: (() => void) | undefined;
    getCurrentWebview().onDragDropEvent(async (event) => {
@@ -489,6 +612,9 @@ function App() {
        const paths = event.payload.paths;
        const mdPath = paths.find((p: string) => p.endsWith('.md') || p.endsWith('.markdown') || p.endsWith('.txt'));
        if (mdPath) {
+          // Guard against duplicate drop events (Windows/WebView2 fires twice)
+          if (pendingDropPaths.current.has(mdPath)) return;
+          pendingDropPaths.current.add(mdPath);
          try {
            const existing = tabsRef.current.find(t => t.path === mdPath);
            if (existing) {
@@ -506,6 +632,8 @@ function App() {
            }
          } catch (err) {
            console.error('Failed to read dropped file:', err);
+          } finally {
+            pendingDropPaths.current.delete(mdPath);
          }
        }
      }
@@ -514,26 +642,33 @@ function App() {
  }, [parseHeadings]);

  // Handle file opened via OS file association (e.g. double-clicking a .md file)
+  useEffect(() => {
+    invoke<{ path: string; content: string } | null>('get_cli_file').then(result => {
+      if (!result) return;
+      const title = result.path.split(/[/\\]/).pop() || 'Untitled';
+      const newTab: Tab = { id: Date.now().toString(), title, content: result.content, path: result.path };
+      setTabs(prev => [...prev, newTab]);
+      setActiveTabId(newTab.id);
+      parseHeadings(result.content);
+    }).catch(err => console.error('Failed to open file from CLI args:', err));
+  }, []);
+
+  // Handle files opened from a second instance (single-instance plugin forwards them here)
  useEffect(() => {
    let unlisten: (() => void) | undefined;
-    listen<string>('open-file', async (event) => {
-      const filePath = event.payload;
-      try {
+    listen<{ path: string; content: string }>('open-file', (event) => {
+      const { path: filePath, content } = event.payload;
      const existing = tabsRef.current.find(t => t.path === filePath);
      if (existing) {
        setActiveTabId(existing.id);
        parseHeadings(existing.content);
      } else {
-          const content = await readTextFile(filePath);
        const title = filePath.split(/[/\\]/).pop() || 'Untitled';
        const newTab: Tab = { id: Date.now().toString(), title, content, path: filePath };
        setTabs(prev => [...prev, newTab]);
        setActiveTabId(newTab.id);
        parseHeadings(content);
      }
-      } catch (err) {
-        console.error('Failed to open file from OS:', err);
-      }
    }).then(fn => { unlisten = fn; });
    return () => { unlisten?.(); };
  }, [parseHeadings]);
@@ -609,10 +744,27 @@ function App() {
        else if (e.shiftKey && e.key === 'S') { e.preventDefault(); setShowSidebar(s => !s); }
      } else if (e.key === 'F11') { e.preventDefault(); setFocusMode(f => !f); }
      else if (e.key === 'Escape') { setShowSearch(false); setShowSidebar(false); }
+      else if (e.key === 'F10' && e.shiftKey) {
+        e.preventDefault();
+        contextMenuTriggerRef.current = document.activeElement;
+        const zf = uiZoom / 100;
+        const focused = document.activeElement as HTMLElement;
+        let x: number, y: number;
+        if (focused && focused !== document.body) {
+          const rect = focused.getBoundingClientRect();
+          x = (rect.left + rect.width / 2) / zf;
+          y = (rect.top + rect.height / 2) / zf;
+        } else {
+          x = window.innerWidth / 2 / zf;
+          y = window.innerHeight / 2 / zf;
+        }
+        const selectedText = window.getSelection()?.toString() || '';
+        setContextMenu({ x, y, selectedText });
+      }
    };
    window.addEventListener('keydown', handleKeyDown);
    return () => window.removeEventListener('keydown', handleKeyDown);
-  }, [handleOpenDialog, closeTab, activeTabId, closeWindow]);
+  }, [handleOpenDialog, closeTab, activeTabId, closeWindow, uiZoom]);

  useEffect(() => {
    const handleWheel = (e: WheelEvent) => {
@@ -683,7 +835,7 @@ function App() {
    };
  }, [activeTabId, showSidebar]);

-  const startSidebarResize = (e: React.MouseEvent) => {
+  const startSidebarResize = (e: React.PointerEvent) => {
    e.preventDefault();
    e.stopPropagation();
    setResizeStartState({ startX: e.clientX, startWidth: sidebarWidth });
@@ -720,17 +872,235 @@ function App() {
    localStorage.setItem('vesper-ui-zoom', String(Math.round(uiZoom)));
  }, [uiZoom]);

+  // Persist theme to localStorage
+  useEffect(() => {
+    localStorage.setItem('vesper-theme', theme);
+  }, [theme]);
+
+  // Menu bar keyboard navigation (WAI-ARIA menu pattern)
+  const handleMenuBarKeyDown = (e: React.KeyboardEvent) => {
+    if (e.key === 'ArrowRight') {
+      e.preventDefault();
+      const next = (menuFocusIndex + 1) % menuItems.length;
+      setMenuFocusIndex(next);
+      menuItemRefs.current[menuItems[next]]?.focus();
+      if (menuOpen) setMenuOpen(menuItems[next]);
+    } else if (e.key === 'ArrowLeft') {
+      e.preventDefault();
+      const prev = (menuFocusIndex - 1 + menuItems.length) % menuItems.length;
+      setMenuFocusIndex(prev);
+      menuItemRefs.current[menuItems[prev]]?.focus();
+      if (menuOpen) setMenuOpen(menuItems[prev]);
+    } else if (e.key === 'ArrowDown' || e.key === 'Enter' || e.key === ' ') {
+      e.preventDefault();
+      setMenuOpen(menuItems[menuFocusIndex]);
+    } else if (e.key === 'Escape') {
+      setMenuOpen(null);
+    }
+  };
+
+  const handleMenuDropdownKeyDown = (e: React.KeyboardEvent) => {
+    const menu = e.currentTarget as HTMLElement;
+    const items = menu.querySelectorAll<HTMLElement>('[role="menuitem"]');
+    if (!items.length) return;
+
+    const currentIndex = Array.from(items).indexOf(document.activeElement as HTMLElement);
+
+    if (e.key === 'ArrowDown') {
+      e.preventDefault();
+      const next = currentIndex < items.length - 1 ? currentIndex + 1 : 0;
+      items[next]?.focus();
+    } else if (e.key === 'ArrowUp') {
+      e.preventDefault();
+      const prev = currentIndex > 0 ? currentIndex - 1 : items.length - 1;
+      items[prev]?.focus();
+    } else if (e.key === 'Home') {
+      e.preventDefault();
+      items[0]?.focus();
+    } else if (e.key === 'End') {
+      e.preventDefault();
+      items[items.length - 1]?.focus();
+    } else if (e.key === 'Escape') {
+      e.preventDefault();
+      setMenuOpen(null);
+      menuItemRefs.current[menuItems[menuFocusIndex]]?.focus();
+    } else if (e.key === 'ArrowRight') {
+      e.preventDefault();
+      const next = (menuFocusIndex + 1) % menuItems.length;
+      setMenuFocusIndex(next);
+      setMenuOpen(menuItems[next]);
+    } else if (e.key === 'ArrowLeft') {
+      e.preventDefault();
+      const prev = (menuFocusIndex - 1 + menuItems.length) % menuItems.length;
+      setMenuFocusIndex(prev);
+      setMenuOpen(menuItems[prev]);
+    }
+  };
+
+  // Tab bar keyboard navigation (WAI-ARIA tabs pattern with roving tabindex)
+  const handleTabListKeyDown = (e: React.KeyboardEvent) => {
+    if (e.key === 'ArrowRight') {
+      e.preventDefault();
+      const next = (tabFocusIndex + 1) % tabs.length;
+      setTabFocusIndex(next);
+      tabRefs.current[next]?.focus();
+    } else if (e.key === 'ArrowLeft') {
+      e.preventDefault();
+      const prev = (tabFocusIndex - 1 + tabs.length) % tabs.length;
+      setTabFocusIndex(prev);
+      tabRefs.current[prev]?.focus();
+    } else if (e.key === 'Home') {
+      e.preventDefault();
+      setTabFocusIndex(0);
+      tabRefs.current[0]?.focus();
+    } else if (e.key === 'End') {
+      e.preventDefault();
+      const last = tabs.length - 1;
+      setTabFocusIndex(last);
+      tabRefs.current[last]?.focus();
+    } else if (e.key === 'Delete') {
+      e.preventDefault();
+      if (tabs[tabFocusIndex]) closeTab(tabs[tabFocusIndex].id);
+    } else if (e.key === 'Enter' || e.key === ' ') {
+      e.preventDefault();
+      const tab = tabs[tabFocusIndex];
+      if (tab) {
+        setActiveTabId(tab.id);
+        parseHeadings(tab.content);
+      }
+    }
+  };
+
+  // Sidebar keyboard navigation (roving tabindex)
+  const handleSidebarKeyDown = (e: React.KeyboardEvent) => {
+    if (headings.length === 0) return;
+
+    if (e.key === 'ArrowDown') {
+      e.preventDefault();
+      const next = Math.min(sidebarFocusIndex + 1, headings.length - 1);
+      setSidebarFocusIndex(next);
+      sidebarItemRefs.current[next]?.focus();
+    } else if (e.key === 'ArrowUp') {
+      e.preventDefault();
+      const prev = Math.max(sidebarFocusIndex - 1, 0);
+      setSidebarFocusIndex(prev);
+      sidebarItemRefs.current[prev]?.focus();
+    } else if (e.key === 'Home') {
+      e.preventDefault();
+      setSidebarFocusIndex(0);
+      sidebarItemRefs.current[0]?.focus();
+    } else if (e.key === 'End') {
+      e.preventDefault();
+      const last = headings.length - 1;
+      setSidebarFocusIndex(last);
+      sidebarItemRefs.current[last]?.focus();
+    } else if (e.key === 'Enter' || e.key === ' ') {
+      e.preventDefault();
+      const heading = headings[sidebarFocusIndex];
+      if (heading) scrollToHeading(heading.text);
+    }
+  };
+
+  // Context menu keyboard navigation (WAI-ARIA menu pattern)
+  const handleContextMenuKeyDown = (e: React.KeyboardEvent) => {
+    const menu = contextMenuRef.current;
+    if (!menu) return;
+    const items = menu.querySelectorAll<HTMLElement>('[role="menuitem"]');
+    if (!items.length) return;
+
+    const currentIndex = Array.from(items).indexOf(document.activeElement as HTMLElement);
+
+    if (e.key === 'ArrowDown') {
+      e.preventDefault();
+      const next = currentIndex < items.length - 1 ? currentIndex + 1 : 0;
+      items[next]?.focus();
+    } else if (e.key === 'ArrowUp') {
+      e.preventDefault();
+      const prev = currentIndex > 0 ? currentIndex - 1 : items.length - 1;
+      items[prev]?.focus();
+    } else if (e.key === 'Home') {
+      e.preventDefault();
+      items[0]?.focus();
+    } else if (e.key === 'End') {
+      e.preventDefault();
+      items[items.length - 1]?.focus();
+    } else if (e.key === 'Escape') {
+      e.preventDefault();
+      setContextMenu(null);
+    }
+  };
+
+  // Auto-focus first menuitem when a dropdown opens
+  useEffect(() => {
+    if (menuOpen) {
+      requestAnimationFrame(() => {
+        const dropdown = document.querySelector('.menu-dropdown[role="menu"]');
+        const firstItem = dropdown?.querySelector<HTMLElement>('[role="menuitem"]');
+        firstItem?.focus();
+      });
+    }
+  }, [menuOpen]);
+
+  // Clamp tabFocusIndex when tabs are closed
+  useEffect(() => {
+    if (tabFocusIndex >= tabs.length && tabs.length > 0) {
+      setTabFocusIndex(tabs.length - 1);
+    }
+  }, [tabs.length, tabFocusIndex]);
+
+  // Active heading tracking via IntersectionObserver
+  useEffect(() => {
+    if (!activeTab || headings.length === 0) {
+      setActiveHeadingText(null);
+      return;
+    }
+
+    const allHeadings = document.querySelectorAll(
+      '.markdown-content h1, .markdown-content h2, .markdown-content h3, .markdown-content h4, .markdown-content h5, .markdown-content h6'
+    );
+
+    if (allHeadings.length === 0) return;
+
+    const observer = new IntersectionObserver(
+      (entries) => {
+        for (const entry of entries) {
+          if (entry.isIntersecting) {
+            setActiveHeadingText(entry.target.textContent?.trim() || null);
+            break;
+          }
+        }
+      },
+      { rootMargin: '0px 0px -70% 0px', threshold: 0.1 }
+    );
+
+    allHeadings.forEach(h => observer.observe(h));
+    return () => observer.disconnect();
+  }, [activeTab, headings, highlightedHtml]);
+
+  // Reset sidebar focus index when headings change
+  useEffect(() => {
+    setSidebarFocusIndex(0);
+  }, [headings]);
+
+  // Scroll the focused tab into view when tabFocusIndex changes
+  useEffect(() => {
+    if (tabs.length > 1) {
+      scrollToTabIndex(tabFocusIndex);
+    }
+  }, [tabFocusIndex, tabs.length, scrollToTabIndex]);
+
  const osScrollbarOptions = {
    scrollbars: { autoHide: 'scroll' as const, autoHideDelay: 800, theme: 'os-theme-dark' as const }
  };

  return (
-    <div className={`app-container ${focusMode ? 'focus-mode' : ''}`} style={{ zoom: `${uiZoom}%` }}>
+    <div className={`app-container ${focusMode ? 'focus-mode' : ''} ${theme === 'light' ? 'theme-light' : ''}`} style={{ zoom: `${uiZoom}%` }}>
+      <a href="#main-content" className="skip-link">Skip to content</a>
      <AnimatePresence>
        {isDraggingOver && (
-          <motion.div className="drop-zone" initial={{ opacity: 0 }} animate={{ opacity: 1 }} exit={{ opacity: 0 }} transition={{ duration: 0.15, ease: materialEase }}>
+          <motion.div className="drop-zone" role="region" aria-label="Drop zone for markdown files" initial={{ opacity: 0 }} animate={{ opacity: 1 }} exit={{ opacity: 0 }} transition={{ duration: 0.15, ease: materialEase }}>
            <motion.div className="drop-zone-content" initial={{ opacity: 0, scale: 0.92, y: 8 }} animate={{ opacity: 1, scale: 1, y: 0 }} exit={{ opacity: 0, scale: 0.92, y: 8 }} transition={{ duration: 0.2, ease: materialEase }}>
-              <motion.div className="drop-zone-icon-wrapper" animate={{ y: [0, -6, 0] }} transition={{ duration: 1.5, repeat: Infinity, ease: 'easeInOut' }}>
+              <motion.div className="drop-zone-icon-wrapper" animate={prefersReducedMotion ? {} : { y: [0, -6, 0] }} transition={prefersReducedMotion ? { duration: 0 } : { duration: 1.5, repeat: Infinity, ease: 'easeInOut' }}>
                <FileDown size={40} strokeWidth={1.5} />
              </motion.div>
              <div className="drop-zone-text">Drop markdown file here</div>
@@ -742,56 +1112,73 @@ function App() {

      <AnimatePresence initial={false}>
        {!focusMode && (
-          <motion.div key="title-bar" className="title-bar" initial={{ height: 0, opacity: 0 }} animate={{ height: 32, opacity: 1 }} exit={{ height: 0, opacity: 0 }} transition={smoothTransition} style={{ overflow: 'hidden' }}>
+          <motion.header key="title-bar" className="title-bar" initial={{ height: 0, opacity: 0 }} animate={{ height: 32, opacity: 1 }} exit={{ height: 0, opacity: 0 }} transition={smoothTransition} style={{ overflow: 'hidden' }}>
            <div className="title-bar-left">
              <div className="title-bar-icon"><FileText size={14} /></div>
              <span className="title-bar-text">Vesper</span>
            </div>
            <div className="title-bar-drag"></div>
            <div className="title-bar-controls">
-              <button className="title-bar-button" onClick={() => appWindow?.minimize()}><Minus size={14} /></button>
-              <button className="title-bar-button" onClick={() => appWindow?.toggleMaximize()}><Square size={12} /></button>
-              <button className="title-bar-button close" onClick={closeWindow}><X size={14} /></button>
+              <button className="title-bar-button" onClick={() => appWindow?.minimize()} aria-label="Minimize"><Minus size={14} /></button>
+              <button className="title-bar-button" onClick={() => appWindow?.toggleMaximize()} aria-label="Maximize"><Square size={12} /></button>
+              <button className="title-bar-button close" onClick={closeWindow} aria-label="Close"><X size={14} /></button>
            </div>
-          </motion.div>
+          </motion.header>
        )}
      </AnimatePresence>

      <AnimatePresence initial={false}>
        {!focusMode && (
-          <motion.div key="menu-bar" className="menu-bar" initial={{ height: 0, opacity: 0 }} animate={{ height: 28, opacity: 1 }} exit={{ height: 0, opacity: 0 }} transition={smoothTransition} style={{ overflow: 'hidden' }}>
-            <div className="menu-item" ref={(el) => { menuItemRefs.current['file'] = el; }} onClick={() => setMenuOpen(prev => prev === 'file' ? null : 'file')}>File</div>
-            <div className="menu-item" ref={(el) => { menuItemRefs.current['view'] = el; }} onClick={() => setMenuOpen(prev => prev === 'view' ? null : 'view')}>View</div>
-            <div className="menu-item" ref={(el) => { menuItemRefs.current['help'] = el; }} onClick={() => setMenuOpen(prev => prev === 'help' ? null : 'help')}>Help</div>
+          <motion.div key="menu-bar" className="menu-bar" role="menubar" onKeyDown={handleMenuBarKeyDown} initial={{ height: 0, opacity: 0 }} animate={{ height: 28, opacity: 1 }} exit={{ height: 0, opacity: 0 }} transition={smoothTransition} style={{ overflow: 'hidden' }}>
+            <button className="menu-item" role="menuitem" aria-haspopup="true" aria-expanded={menuOpen === 'file'} tabIndex={menuFocusIndex === 0 ? 0 : -1} ref={(el) => { menuItemRefs.current['file'] = el; }} onClick={() => { setMenuFocusIndex(0); setMenuOpen(prev => prev === 'file' ? null : 'file'); }}>File</button>
+            <button className="menu-item" role="menuitem" aria-haspopup="true" aria-expanded={menuOpen === 'view'} tabIndex={menuFocusIndex === 1 ? 0 : -1} ref={(el) => { menuItemRefs.current['view'] = el; }} onClick={() => { setMenuFocusIndex(1); setMenuOpen(prev => prev === 'view' ? null : 'view'); }}>View</button>
+            <button className="menu-item" role="menuitem" aria-haspopup="true" aria-expanded={menuOpen === 'help'} tabIndex={menuFocusIndex === 2 ? 0 : -1} ref={(el) => { menuItemRefs.current['help'] = el; }} onClick={() => { setMenuFocusIndex(2); setMenuOpen(prev => prev === 'help' ? null : 'help'); }}>Help</button>
            <AnimatePresence>
              {menuOpen === 'file' && menuItemRefs.current['file'] && (
-                <motion.div className="menu-dropdown" initial={{ opacity: 0, y: -5 }} animate={{ opacity: 1, y: 0 }} exit={{ opacity: 0, y: -5 }} transition={smoothTransition} style={{ position: 'fixed', left: menuItemRefs.current['file']!.getBoundingClientRect().left, top: menuItemRefs.current['file']!.getBoundingClientRect().bottom - 6 }}>
-                  <button className="menu-dropdown-item" onClick={() => { handleOpenDialog(); setMenuOpen(null); }}>Open File <span className="menu-shortcut">Ctrl+O</span></button>
-                  <button className="menu-dropdown-item" onClick={() => { if (activeTabId) closeTab(activeTabId); setMenuOpen(null); }}>Close Tab <span className="menu-shortcut">Ctrl+W</span></button>
+                <motion.div className="menu-dropdown" role="menu" onKeyDown={handleMenuDropdownKeyDown} initial={{ opacity: 0, y: -5 }} animate={{ opacity: 1, y: 0 }} exit={{ opacity: 0, y: -5 }} transition={smoothTransition} style={{ position: 'fixed', left: menuItemRefs.current['file']!.getBoundingClientRect().left, top: menuItemRefs.current['file']!.getBoundingClientRect().bottom - 6 }}>
+                  <button className="menu-dropdown-item" role="menuitem" onClick={() => { handleOpenDialog(); setMenuOpen(null); }}>Open File <span className="menu-shortcut">Ctrl+O</span></button>
+                  <button className="menu-dropdown-item" role="menuitem" onClick={() => { if (activeTabId) closeTab(activeTabId); setMenuOpen(null); }}>Close Tab <span className="menu-shortcut">Ctrl+W</span></button>
                  <div className="menu-separator"></div>
-                  <button className="menu-dropdown-item" onClick={() => { closeWindow(); setMenuOpen(null); }}>Exit <span className="menu-shortcut">Ctrl+Q</span></button>
+                  <button className="menu-dropdown-item" role="menuitem" onClick={() => { closeWindow(); setMenuOpen(null); }}>Exit <span className="menu-shortcut">Ctrl+Q</span></button>
                </motion.div>
              )}
              {menuOpen === 'view' && menuItemRefs.current['view'] && (
-                <motion.div className="menu-dropdown" initial={{ opacity: 0, y: -5 }} animate={{ opacity: 1, y: 0 }} exit={{ opacity: 0, y: -5 }} transition={smoothTransition} style={{ position: 'fixed', left: menuItemRefs.current['view']!.getBoundingClientRect().left, top: menuItemRefs.current['view']!.getBoundingClientRect().bottom - 6 }}>
-                  <button className="menu-dropdown-item" onClick={() => { setShowSearch(s => !s); setMenuOpen(null); }}>Toggle Search <span className="menu-shortcut">Ctrl+F</span></button>
-                  <button className="menu-dropdown-item" onClick={() => { setShowSidebar(s => !s); setMenuOpen(null); }}>Toggle Sidebar <span className="menu-shortcut">Ctrl+Shift+S</span></button>
-                  <button className="menu-dropdown-item" onClick={() => { setFocusMode(f => !f); setMenuOpen(null); }}>Focus Mode <span className="menu-shortcut">F11</span></button>
+                <motion.div className="menu-dropdown" role="menu" onKeyDown={handleMenuDropdownKeyDown} initial={{ opacity: 0, y: -5 }} animate={{ opacity: 1, y: 0 }} exit={{ opacity: 0, y: -5 }} transition={smoothTransition} style={{ position: 'fixed', left: menuItemRefs.current['view']!.getBoundingClientRect().left, top: menuItemRefs.current['view']!.getBoundingClientRect().bottom - 6 }}>
+                  <button className="menu-dropdown-item" role="menuitem" onClick={() => { setShowSearch(s => !s); setMenuOpen(null); }}>Toggle Search <span className="menu-shortcut">Ctrl+F</span></button>
+                  <button className="menu-dropdown-item" role="menuitem" onClick={() => { setShowSidebar(s => !s); setMenuOpen(null); }}>Toggle Sidebar <span className="menu-shortcut">Ctrl+Shift+S</span></button>
+                  <button className="menu-dropdown-item" role="menuitem" onClick={() => { setFocusMode(f => !f); setMenuOpen(null); }}>Focus Mode <span className="menu-shortcut">F11</span></button>
+                  <button className="menu-dropdown-item" role="menuitem" onClick={() => { setTheme(t => t === 'dark' ? 'light' : 'dark'); setMenuOpen(null); }}>Theme: {theme === 'dark' ? 'Dark' : 'Light'} <span className="menu-shortcut">{theme === 'dark' ? 'Switch to Light' : 'Switch to Dark'}</span></button>
                  <div className="menu-separator"></div>
                  <div className="menu-dropdown-zoom" onClick={e => e.stopPropagation()}>
                    <span>UI Scale</span>
-                    <div className="zoom-spinner">
-                      <button className="zoom-spinner-btn" onClick={() => setUiZoom(z => Math.max(50, z - 10))}><Minus size={12} /></button>
+                    <div className="zoom-spinner" aria-label="UI Scale">
+                      <button className="zoom-spinner-btn" aria-label="Decrease UI scale" onClick={() => setUiZoom(z => Math.max(50, z - 10))}><Minus size={12} /></button>
                      <span className="zoom-spinner-value">{uiZoom}%</span>
-                      <button className="zoom-spinner-btn" onClick={() => setUiZoom(z => Math.min(200, z + 10))}><Plus size={12} /></button>
+                      <button className="zoom-spinner-btn" aria-label="Increase UI scale" onClick={() => setUiZoom(z => Math.min(200, z + 10))}><Plus size={12} /></button>
+                    </div>
+                  </div>
+                  <div className="menu-dropdown-zoom" onClick={e => e.stopPropagation()}>
+                    <span>Content Zoom</span>
+                    <div className="zoom-spinner" aria-label="Content Zoom">
+                      <button className="zoom-spinner-btn" aria-label="Decrease content zoom" onClick={() => setZoom(z => Math.max(50, z - 10))}><Minus size={12} /></button>
+                      <span className="zoom-spinner-value">{zoom}%</span>
+                      <button className="zoom-spinner-btn" aria-label="Increase content zoom" onClick={() => setZoom(z => Math.min(200, z + 10))}><Plus size={12} /></button>
+                    </div>
+                  </div>
+                  <div className="menu-dropdown-zoom" onClick={e => e.stopPropagation()}>
+                    <span>Content Width</span>
+                    <div className="zoom-spinner" aria-label="Content Width">
+                      <button className="zoom-spinner-btn" aria-label="Decrease content width" onClick={() => setContentWidth(w => Math.max(400, w - 40))}><Minus size={12} /></button>
+                      <span className="zoom-spinner-value">{contentWidth}px</span>
+                      <button className="zoom-spinner-btn" aria-label="Increase content width" onClick={() => setContentWidth(w => Math.min(1200, w + 40))}><Plus size={12} /></button>
                    </div>
                  </div>
                </motion.div>
              )}
              {menuOpen === 'help' && menuItemRefs.current['help'] && (
-                <motion.div className="menu-dropdown" initial={{ opacity: 0, y: -5 }} animate={{ opacity: 1, y: 0 }} exit={{ opacity: 0, y: -5 }} transition={smoothTransition} style={{ position: 'fixed', left: menuItemRefs.current['help']!.getBoundingClientRect().left, top: menuItemRefs.current['help']!.getBoundingClientRect().bottom - 6 }}>
-                  <button className="menu-dropdown-item" onClick={() => { setShowShortcutsModal(true); setMenuOpen(null); }}>Keyboard Shortcuts</button>
-                  <button className="menu-dropdown-item" onClick={() => { setShowAboutModal(true); setMenuOpen(null); }}>About Vesper</button>
+                <motion.div className="menu-dropdown" role="menu" onKeyDown={handleMenuDropdownKeyDown} initial={{ opacity: 0, y: -5 }} animate={{ opacity: 1, y: 0 }} exit={{ opacity: 0, y: -5 }} transition={smoothTransition} style={{ position: 'fixed', left: menuItemRefs.current['help']!.getBoundingClientRect().left, top: menuItemRefs.current['help']!.getBoundingClientRect().bottom - 6 }}>
+                  <button className="menu-dropdown-item" role="menuitem" onClick={() => { setShowShortcutsModal(true); setMenuOpen(null); }}>Keyboard Shortcuts</button>
+                  <button className="menu-dropdown-item" role="menuitem" onClick={() => { setShowAboutModal(true); setMenuOpen(null); }}>About Vesper</button>
                </motion.div>
              )}
            </AnimatePresence>
@@ -802,18 +1189,18 @@ function App() {
      <AnimatePresence>
        {tabs.length > 1 && (
          <motion.div className="tab-bar" initial={{ height: 0, opacity: 0 }} animate={{ height: 38, opacity: 1 }} exit={{ height: 0, opacity: 0 }} transition={{ duration: 0.25, ease: materialEase }}>
-            <button className={`tab-scroll-arrow ${tabScrollState.canLeft ? 'visible' : ''}`} onMouseDown={() => startScrollingTabs('left')} onMouseUp={stopScrollingTabs} onMouseLeave={stopScrollingTabs}><ChevronLeft size={14} /></button>
-            <div className="tab-scroll-container" ref={tabScrollRef}>
+            <button className={`tab-scroll-arrow ${tabScrollState.canLeft ? 'visible' : ''}`} aria-label="Scroll tabs left" onPointerDown={() => startScrollingTabs('left')} onPointerUp={stopScrollingTabs} onPointerLeave={stopScrollingTabs}><ChevronLeft size={14} /></button>
+            <div className="tab-scroll-container" ref={tabScrollRef} role="tablist" onKeyDown={handleTabListKeyDown}>
              <AnimatePresence initial={false}>
-                {tabs.map(tab => (
-                  <motion.div layout key={tab.id} className={`tab ${tab.id === activeTabId ? 'active' : ''}`} initial={{ opacity: 0, scale: 0.9 }} animate={{ opacity: 1, scale: 1 }} exit={{ opacity: 0, scale: 0.9 }} transition={smoothTransition} onClick={() => { setActiveTabId(tab.id); parseHeadings(tab.content); }}>
+                {tabs.map((tab, index) => (
+                  <motion.div layout key={tab.id} id={`tab-${tab.id}`} role="tab" aria-selected={tab.id === activeTabId} tabIndex={index === tabFocusIndex ? 0 : -1} ref={(el) => { tabRefs.current[index] = el; }} className={`tab ${tab.id === activeTabId ? 'active' : ''}`} initial={{ opacity: 0, scale: 0.9 }} animate={{ opacity: 1, scale: 1 }} exit={{ opacity: 0, scale: 0.9 }} transition={smoothTransition} onClick={() => { setTabFocusIndex(index); setActiveTabId(tab.id); parseHeadings(tab.content); }}>
                    <span className="tab-title">{tab.title}</span>
-                    <button className="tab-close" onClick={(e) => { e.stopPropagation(); closeTab(tab.id); }}><X size={12} /></button>
+                    <button className="tab-close" aria-label="Close tab" onClick={(e) => { e.stopPropagation(); closeTab(tab.id); }}><X size={12} /></button>
                  </motion.div>
                ))}
              </AnimatePresence>
            </div>
-            <button className={`tab-scroll-arrow ${tabScrollState.canRight ? 'visible' : ''}`} onMouseDown={() => startScrollingTabs('right')} onMouseUp={stopScrollingTabs} onMouseLeave={stopScrollingTabs}><ChevronRight size={14} /></button>
+            <button className={`tab-scroll-arrow ${tabScrollState.canRight ? 'visible' : ''}`} aria-label="Scroll tabs right" onPointerDown={() => startScrollingTabs('right')} onPointerUp={stopScrollingTabs} onPointerLeave={stopScrollingTabs}><ChevronRight size={14} /></button>
          </motion.div>
        )}
      </AnimatePresence>
@@ -821,46 +1208,72 @@ function App() {
      <div className="main-content">
        <AnimatePresence initial={false}>
          {showSidebar && (
-            <motion.div className="sidebar-scroll-wrapper" initial={{ width: 0, opacity: 0 }} animate={{ width: sidebarWidth, opacity: 1 }} exit={{ width: 0, opacity: 0 }} transition={resizeStartState ? { duration: 0 } : smoothTransition} style={{ height: '100%' }}>
+            <motion.nav className="sidebar-scroll-wrapper" aria-label="Table of Contents" initial={{ width: 0, opacity: 0 }} animate={{ width: sidebarWidth, opacity: 1 }} exit={{ width: 0, opacity: 0 }} transition={resizeStartState ? { duration: 0 } : smoothTransition} style={{ height: '100%' }}>
              <OverlayScrollbarsComponent options={osScrollbarOptions} style={{ height: '100%' }}>
-                <div className="sidebar" ref={sidebarRef}>
-                  <div className="sidebar-heading">Contents</div>
+                <div className="sidebar" ref={sidebarRef} onKeyDown={handleSidebarKeyDown}>
+                  <h2 className="sidebar-heading">Contents</h2>
                  {headings.length > 0
-                    ? headings.map(h => <button key={h.id} className={`sidebar-item h${h.level}`} onClick={() => scrollToHeading(h.text)}>{h.text}</button>)
+                    ? headings.map((h, index) => (
+                      <button
+                        key={h.id}
+                        ref={(el) => { sidebarItemRefs.current[index] = el; }}
+                        className={`sidebar-item h${h.level}${h.text === activeHeadingText ? ' active' : ''}`}
+                        tabIndex={index === sidebarFocusIndex ? 0 : -1}
+                        onClick={() => { setSidebarFocusIndex(index); scrollToHeading(h.text); }}
+                      >
+                        {h.text}
+                      </button>
+                    ))
                    : <div className="sidebar-empty">No headings</div>
                  }
                </div>
              </OverlayScrollbarsComponent>
-              <div className="sidebar-resize-handle" onMouseDown={startSidebarResize}></div>
-            </motion.div>
+              <div
+                className="sidebar-resize-handle"
+                role="separator"
+                aria-orientation="vertical"
+                aria-label="Resize sidebar"
+                tabIndex={0}
+                onPointerDown={startSidebarResize}
+                onKeyDown={(e) => {
+                  if (e.key === 'ArrowRight') {
+                    e.preventDefault();
+                    setSidebarWidth(w => Math.min(400, w + (e.shiftKey ? 50 : 10)));
+                  } else if (e.key === 'ArrowLeft') {
+                    e.preventDefault();
+                    setSidebarWidth(w => Math.max(150, w - (e.shiftKey ? 50 : 10)));
+                  }
+                }}
+              ></div>
+            </motion.nav>
          )}
        </AnimatePresence>

-        <div className="content-column">
+        <main id="main-content" className="content-column">
          <AnimatePresence>
            {showSearch && activeTab && (
-              <motion.div className="search-bar" initial={{ opacity: 0, y: -10 }} animate={{ opacity: 1, y: 0 }} exit={{ opacity: 0, y: -10 }} transition={smoothTransition}>
-                <input ref={searchInputRef} type="text" className="search-input" placeholder="Search..." value={searchQuery} onChange={e => { setSearchQuery(e.target.value); }} onKeyDown={e => { if (e.key === 'Enter') { e.preventDefault(); setCurrentMatchIndex(i => (i + 1) % Math.max(searchMatches.length, 1)); setSearchTriggerCount(c => c + 1); } }} autoFocus />
+              <motion.search className="search-bar" initial={{ opacity: 0, y: -10 }} animate={{ opacity: 1, y: 0 }} exit={{ opacity: 0, y: -10 }} transition={smoothTransition}>
+                <input ref={searchInputRef} type="text" className="search-input" placeholder="Search..." value={searchQuery} onChange={e => { setSearchQuery(e.target.value); }} onKeyDown={e => { if (e.key === 'Enter') { e.preventDefault(); setCurrentMatchIndex(i => (i + 1) % Math.max(searchMatches.length, 1)); setSearchTriggerCount(c => c + 1); } }} aria-label="Search document" autoFocus />
                {searchMatches.length > 0 && (
                  <>
-                    <button className="search-nav-btn" onClick={() => { setCurrentMatchIndex(i => (i - 1 + searchMatches.length) % searchMatches.length); setSearchTriggerCount(c => c + 1); }}><ChevronLeft size={16} /></button>
-                    <span className="search-results">{currentMatchIndex + 1} of {searchMatches.length}</span>
-                    <button className="search-nav-btn" onClick={() => { setCurrentMatchIndex(i => (i + 1) % searchMatches.length); setSearchTriggerCount(c => c + 1); }}><ChevronRight size={16} /></button>
+                    <button className="search-nav-btn" aria-label="Previous match" onClick={() => { setCurrentMatchIndex(i => (i - 1 + searchMatches.length) % searchMatches.length); setSearchTriggerCount(c => c + 1); }}><ChevronLeft size={16} /></button>
+                    <span className="search-results" role="status" aria-live="polite">{currentMatchIndex + 1} of {searchMatches.length}</span>
+                    <button className="search-nav-btn" aria-label="Next match" onClick={() => { setCurrentMatchIndex(i => (i + 1) % searchMatches.length); setSearchTriggerCount(c => c + 1); }}><ChevronRight size={16} /></button>
                  </>
                )}
-                {searchQuery && searchMatches.length === 0 && <span className="search-results">No results</span>}
-              </motion.div>
+                {searchQuery && searchMatches.length === 0 && <span className="search-results" role="status" aria-live="polite">No results</span>}
+              </motion.search>
            )}
          </AnimatePresence>

-          <motion.div className="content-area-scroll-wrapper" key={activeTabId} initial={{ opacity: 0 }} animate={{ opacity: 1 }} transition={smoothTransition}>
+          <motion.div className="content-area-scroll-wrapper" role="tabpanel" aria-labelledby={activeTabId ? `tab-${activeTabId}` : undefined} key={activeTabId} initial={{ opacity: 0 }} animate={{ opacity: 1 }} transition={smoothTransition}>
            <OverlayScrollbarsComponent options={osScrollbarOptions} style={{ height: '100%' }}>
              <div className="content-area-scroll" ref={contentRef} style={{ zoom: `${(zoom / uiZoom) * 100}%`, ...(!activeTab ? { height: '100%' } : {}) }}>
                {activeTab ? (
                  <article className="markdown-content" style={{ maxWidth: contentWidth }} dangerouslySetInnerHTML={{ __html: highlightedHtml }} />
                ) : (
                  <motion.div className="welcome-screen" initial={{ opacity: 0, scale: 0.95 }} animate={{ opacity: 1, scale: 1 }} transition={smoothTransition}>
-                    <motion.div className="welcome-icon" animate={{ y: [0, -5, 0] }} transition={{ duration: 2, repeat: Infinity }}><FolderOpen size={64} /></motion.div>
+                    <motion.div className="welcome-icon" animate={prefersReducedMotion ? {} : { y: [0, -5, 0] }} transition={prefersReducedMotion ? { duration: 0 } : { duration: 2, repeat: Infinity }}><FolderOpen size={64} /></motion.div>
                    <h1 className="welcome-title">Vesper</h1>
                    <p className="welcome-subtitle">A beautiful markdown reader</p>
                    <button className="welcome-button" onClick={handleOpenDialog}>Open File (Ctrl+O)</button>
@@ -870,16 +1283,16 @@ function App() {
              </div>
            </OverlayScrollbarsComponent>
          </motion.div>
-        </div>
+        </main>
      </div>

      <AnimatePresence>
        {showShortcutsModal && (
-          <motion.div className="modal-overlay" initial={{ opacity: 0 }} animate={{ opacity: 1 }} exit={{ opacity: 0 }} transition={smoothTransition} onClick={() => setShowShortcutsModal(false)}>
-            <motion.div className="shortcuts-dialog" initial={{ opacity: 0, scale: 0.95 }} animate={{ opacity: 1, scale: 1 }} exit={{ opacity: 0, scale: 0.95 }} transition={smoothTransition} onClick={e => e.stopPropagation()}>
+          <motion.div className="modal-overlay" initial={{ opacity: 0 }} animate={{ opacity: 1 }} exit={{ opacity: 0 }} transition={smoothTransition} onClick={() => setShowShortcutsModal(false)} onKeyDown={(e) => { if (e.key === 'Escape') setShowShortcutsModal(false); }}>
+            <motion.div ref={shortcutsModalRef} className="shortcuts-dialog" role="dialog" aria-modal="true" aria-labelledby="shortcuts-title" initial={{ opacity: 0, scale: 0.95 }} animate={{ opacity: 1, scale: 1 }} exit={{ opacity: 0, scale: 0.95 }} transition={smoothTransition} onClick={e => e.stopPropagation()}>
              <div className="shortcuts-dialog-header">
-                <h2 className="shortcuts-dialog-title">Keyboard Shortcuts</h2>
-                <button className="shortcuts-dialog-close" onClick={() => setShowShortcutsModal(false)}><X size={16} /></button>
+                <h2 className="shortcuts-dialog-title" id="shortcuts-title">Keyboard Shortcuts</h2>
+                <button className="shortcuts-dialog-close" aria-label="Close dialog" onClick={() => setShowShortcutsModal(false)}><X size={16} /></button>
              </div>
              <div className="shortcuts-dialog-body">
                <div>
@@ -907,11 +1320,11 @@ function App() {
          </motion.div>
        )}
        {showAboutModal && (
-          <motion.div className="modal-overlay" initial={{ opacity: 0 }} animate={{ opacity: 1 }} exit={{ opacity: 0 }} transition={smoothTransition} onClick={() => setShowAboutModal(false)}>
-            <motion.div className="modal" initial={{ opacity: 0, scale: 0.95 }} animate={{ opacity: 1, scale: 1 }} exit={{ opacity: 0, scale: 0.95 }} transition={smoothTransition} onClick={e => e.stopPropagation()}>
+          <motion.div className="modal-overlay" initial={{ opacity: 0 }} animate={{ opacity: 1 }} exit={{ opacity: 0 }} transition={smoothTransition} onClick={() => setShowAboutModal(false)} onKeyDown={(e) => { if (e.key === 'Escape') setShowAboutModal(false); }}>
+            <motion.div ref={aboutModalRef} className="modal" role="dialog" aria-modal="true" aria-labelledby="about-title" initial={{ opacity: 0, scale: 0.95 }} animate={{ opacity: 1, scale: 1 }} exit={{ opacity: 0, scale: 0.95 }} transition={smoothTransition} onClick={e => e.stopPropagation()}>
              <div className="modal-header">
-                <h2 className="modal-title">About Vesper</h2>
-                <button className="modal-close" onClick={() => setShowAboutModal(false)}><X size={16} /></button>
+                <h2 className="modal-title" id="about-title">About Vesper</h2>
+                <button className="modal-close" aria-label="Close dialog" onClick={() => setShowAboutModal(false)}><X size={16} /></button>
              </div>
              <div className="modal-content about-content">
                <div className="about-icon"><FileText size={48} /></div>
@@ -927,7 +1340,7 @@ function App() {

      <AnimatePresence>
        {menuOpen && (
-          <div className="menu-backdrop" onClick={() => setMenuOpen(null)} />
+          <div className="menu-backdrop" aria-hidden="true" onClick={() => setMenuOpen(null)} />
        )}
      </AnimatePresence>

@@ -941,23 +1354,23 @@ function App() {

      <AnimatePresence>
        {contextMenu && (
-          <motion.div ref={contextMenuRef} className="context-menu" style={{ left: contextMenu.x, top: contextMenu.y }} initial={{ opacity: 0, scale: 0.95 }} animate={{ opacity: 1, scale: 1 }} exit={{ opacity: 0, scale: 0.95 }} transition={smoothTransition}>
+          <motion.div ref={contextMenuRef} className="context-menu" role="menu" onKeyDown={handleContextMenuKeyDown} style={{ left: contextMenu.x, top: contextMenu.y }} initial={{ opacity: 0, scale: 0.95 }} animate={{ opacity: 1, scale: 1 }} exit={{ opacity: 0, scale: 0.95 }} transition={smoothTransition}>
            {contextMenu.selectedText && (
              <>
-                <button className="context-menu-item" onClick={() => { navigator.clipboard.writeText(contextMenu.selectedText); setContextMenu(null); }}>Copy</button>
+                <button className="context-menu-item" role="menuitem" onClick={() => { navigator.clipboard.writeText(contextMenu.selectedText); setContextMenu(null); }}>Copy</button>
                <div className="context-menu-separator"></div>
              </>
            )}
-            <button className="context-menu-item" onClick={() => { handleOpenDialog(); setContextMenu(null); }}>Open File</button>
+            <button className="context-menu-item" role="menuitem" onClick={() => { handleOpenDialog(); setContextMenu(null); }}>Open File</button>
            <div className="context-menu-separator"></div>
-            <button className="context-menu-item" onClick={() => { setShowSearch(s => !s); setContextMenu(null); }}>Toggle Search</button>
-            <button className="context-menu-item" onClick={() => { setShowSidebar(s => !s); setContextMenu(null); }}>Toggle Sidebar</button>
-            <button className="context-menu-item" onClick={() => { setFocusMode(f => !f); setContextMenu(null); }}>Focus Mode</button>
+            <button className="context-menu-item" role="menuitem" onClick={() => { setShowSearch(s => !s); setContextMenu(null); }}>Toggle Search</button>
+            <button className="context-menu-item" role="menuitem" onClick={() => { setShowSidebar(s => !s); setContextMenu(null); }}>Toggle Sidebar</button>
+            <button className="context-menu-item" role="menuitem" onClick={() => { setFocusMode(f => !f); setContextMenu(null); }}>Focus Mode</button>
            <div className="context-menu-separator"></div>
-            <button className="context-menu-item" onClick={() => { setShowShortcutsModal(true); setContextMenu(null); }}>Keyboard Shortcuts</button>
-            <button className="context-menu-item" onClick={() => { setShowAboutModal(true); setContextMenu(null); }}>About</button>
+            <button className="context-menu-item" role="menuitem" onClick={() => { setShowShortcutsModal(true); setContextMenu(null); }}>Keyboard Shortcuts</button>
+            <button className="context-menu-item" role="menuitem" onClick={() => { setShowAboutModal(true); setContextMenu(null); }}>About</button>
            <div className="context-menu-separator"></div>
-            <button className="context-menu-item" onClick={() => { closeWindow(); setContextMenu(null); }}>Exit <span className="menu-shortcut">Ctrl+Q</span></button>
+            <button className="context-menu-item" role="menuitem" onClick={() => { closeWindow(); setContextMenu(null); }}>Exit <span className="menu-shortcut">Ctrl+Q</span></button>
          </motion.div>
        )}
      </AnimatePresence>
--- a/src/assets/react.svg
+++ b/src/assets/react.svg
@@ -1 +0,0 @@
-<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" class="iconify iconify--logos" width="35.93" height="32" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 228"><path fill="#00D8FF" d="M210.483 73.824a171.49 171.49 0 0 0-8.24-2.597c.465-1.9.893-3.777 1.273-5.621c6.238-30.281 2.16-54.676-11.769-62.708c-13.355-7.7-35.196.329-57.254 19.526a171.23 171.23 0 0 0-6.375 5.848a155.866 155.866 0 0 0-4.241-3.917C100.759 3.829 77.587-4.822 63.673 3.233C50.33 10.957 46.379 33.89 51.995 62.588a170.974 170.974 0 0 0 1.892 8.48c-3.28.932-6.445 1.924-9.474 2.98C17.309 83.498 0 98.307 0 113.668c0 15.865 18.582 31.778 46.812 41.427a145.52 145.52 0 0 0 6.921 2.165a167.467 167.467 0 0 0-2.01 9.138c-5.354 28.2-1.173 50.591 12.134 58.266c13.744 7.926 36.812-.22 59.273-19.855a145.567 145.567 0 0 0 5.342-4.923a168.064 168.064 0 0 0 6.92 6.314c21.758 18.722 43.246 26.282 56.54 18.586c13.731-7.949 18.194-32.003 12.4-61.268a145.016 145.016 0 0 0-1.535-6.842c1.62-.48 3.21-.974 4.76-1.488c29.348-9.723 48.443-25.443 48.443-41.52c0-15.417-17.868-30.326-45.517-39.844Zm-6.365 70.984c-1.4.463-2.836.91-4.3 1.345c-3.24-10.257-7.612-21.163-12.963-32.432c5.106-11 9.31-21.767 12.459-31.957c2.619.758 5.16 1.557 7.61 2.4c23.69 8.156 38.14 20.213 38.14 29.504c0 9.896-15.606 22.743-40.946 31.14Zm-10.514 20.834c2.562 12.94 2.927 24.64 1.23 33.787c-1.524 8.219-4.59 13.698-8.382 15.893c-8.067 4.67-25.32-1.4-43.927-17.412a156.726 156.726 0 0 1-6.437-5.87c7.214-7.889 14.423-17.06 21.459-27.246c12.376-1.098 24.068-2.894 34.671-5.345a134.17 134.17 0 0 1 1.386 6.193ZM87.276 214.515c-7.882 2.783-14.16 2.863-17.955.675c-8.075-4.657-11.432-22.636-6.853-46.752a156.923 156.923 0 0 1 1.869-8.499c10.486 2.32 22.093 3.988 34.498 4.994c7.084 9.967 14.501 19.128 21.976 27.15a134.668 134.668 0 0 1-4.877 4.492c-9.933 8.682-19.886 14.842-28.658 17.94ZM50.35 144.747c-12.483-4.267-22.792-9.812-29.858-15.863c-6.35-5.437-9.555-10.836-9.555-15.216c0-9.322 13.897-21.212 37.076-29.293c2.813-.98 5.757-1.905 8.812-2.773c3.204 10.42 7.406 21.315 12.477 32.332c-5.137 11.18-9.399 22.249-12.634 32.792a134.718 134.718 0 0 1-6.318-1.979Zm12.378-84.26c-4.811-24.587-1.616-43.134 6.425-47.789c8.564-4.958 27.502 2.111 47.463 19.835a144.318 144.318 0 0 1 3.841 3.545c-7.438 7.987-14.787 17.08-21.808 26.988c-12.04 1.116-23.565 2.908-34.161 5.309a160.342 160.342 0 0 1-1.76-7.887Zm110.427 27.268a347.8 347.8 0 0 0-7.785-12.803c8.168 1.033 15.994 2.404 23.343 4.08c-2.206 7.072-4.956 14.465-8.193 22.045a381.151 381.151 0 0 0-7.365-13.322Zm-45.032-43.861c5.044 5.465 10.096 11.566 15.065 18.186a322.04 322.04 0 0 0-30.257-.006c4.974-6.559 10.069-12.652 15.192-18.18ZM82.802 87.83a323.167 323.167 0 0 0-7.227 13.238c-3.184-7.553-5.909-14.98-8.134-22.152c7.304-1.634 15.093-2.97 23.209-3.984a321.524 321.524 0 0 0-7.848 12.897Zm8.081 65.352c-8.385-.936-16.291-2.203-23.593-3.793c2.26-7.3 5.045-14.885 8.298-22.6a321.187 321.187 0 0 0 7.257 13.246c2.594 4.48 5.28 8.868 8.038 13.147Zm37.542 31.03c-5.184-5.592-10.354-11.779-15.403-18.433c4.902.192 9.899.29 14.978.29c5.218 0 10.376-.117 15.453-.343c-4.985 6.774-10.018 12.97-15.028 18.486Zm52.198-57.817c3.422 7.8 6.306 15.345 8.596 22.52c-7.422 1.694-15.436 3.058-23.88 4.071a382.417 382.417 0 0 0 7.859-13.026a347.403 347.403 0 0 0 7.425-13.565Zm-16.898 8.101a358.557 358.557 0 0 1-12.281 19.815a329.4 329.4 0 0 1-23.444.823c-7.967 0-15.716-.248-23.178-.732a310.202 310.202 0 0 1-12.513-19.846h.001a307.41 307.41 0 0 1-10.923-20.627a310.278 310.278 0 0 1 10.89-20.637l-.001.001a307.318 307.318 0 0 1 12.413-19.761c7.613-.576 15.42-.876 23.31-.876H128c7.926 0 15.743.303 23.354.883a329.357 329.357 0 0 1 12.335 19.695a358.489 358.489 0 0 1 11.036 20.54a329.472 329.472 0 0 1-11 20.722Zm22.56-122.124c8.572 4.944 11.906 24.881 6.52 51.026c-.344 1.668-.73 3.367-1.15 5.09c-10.622-2.452-22.155-4.275-34.23-5.408c-7.034-10.017-14.323-19.124-21.64-27.008a160.789 160.789 0 0 1 5.888-5.4c18.9-16.447 36.564-22.941 44.612-18.3ZM128 90.808c12.625 0 22.86 10.235 22.86 22.86s-10.235 22.86-22.86 22.86s-22.86-10.235-22.86-22.86s10.235-22.86 22.86-22.86Z"></path></svg>
--- a/src/styles.css
+++ b/src/styles.css
@@ -54,16 +54,53 @@
  
  /* Text hierarchy */
  --color-text-primary: #E4E6EB;
-  --color-text-secondary: #ABB0B8;
-  --color-text-tertiary: #6B7280;
-  --color-text-disabled: #4A5260;
+  --color-text-secondary: #BCC1C8;   /* was #ABB0B8, now ~7.5:1 */
+  --color-text-tertiary: #8B919A;    /* was #6B7280, now ~4.8:1 */
+  --color-text-disabled: #6B7280;    /* was #4A5260, now ~2.9:1 (exempt - inactive UI) */
  
  /* Accent */
  --color-accent: #6B8AFF;
  --color-accent-hover: #8BA3FF;
+  --color-accent-small: #8BA3FF;     /* for small text (11px) accent uses */
  --color-accent-muted: rgba(107, 138, 255, 0.12);
  --color-accent-subtle: rgba(107, 138, 255, 0.06);

+  /* Markdown typography */
+  --color-md-h1: #F5F6F7;
+  --color-md-h2: #EDEEF0;
+  --color-md-h3: #E4E5E8;
+  --color-md-h4: #D8DADE;
+  --color-md-h5: #CBCED3;
+  --color-md-h6: #BCC1C8;
+  --color-md-heading: #F0F1F3;
+  --color-md-paragraph: #C8CCD0;
+  --color-md-link: #93B8F9;
+  --color-md-link-underline: rgba(147, 184, 249, 0.3);
+  --color-md-link-hover: #A8C6FA;
+  --color-md-link-hover-underline: rgba(168, 198, 250, 0.7);
+  --color-md-marker: #93B8F9;
+  --color-md-blockquote-border: #93B8F9;
+  --color-md-blockquote-bg: rgba(147, 184, 249, 0.04);
+  --color-md-blockquote-text: #BFC3C8;
+  --color-md-code-inline: #E8B89E;
+  --color-md-code-inline-bg: rgba(255, 255, 255, 0.06);
+  --color-md-code-block-bg: #1A1D24;
+  --color-md-code-block-border: rgba(255, 255, 255, 0.06);
+  --color-md-code-text: #E4E6EB;
+  --color-md-table-header-bg: rgba(124, 169, 247, 0.08);
+  --color-md-table-border: rgba(255, 255, 255, 0.06);
+  --color-md-table-cell: #C8CCD0;
+  --color-md-table-stripe: rgba(30, 33, 40, 0.4);
+  --color-md-table-hover: rgba(124, 169, 247, 0.05);
+  --color-md-hr: rgba(255, 255, 255, 0.1);
+  --color-md-mark-bg: rgba(251, 191, 36, 0.2);
+  --color-md-mark-text: #FBBF24;
+  --color-md-comment: #7C8390;
+  --color-md-highlight-bg: rgba(251, 191, 36, 0.3);
+  --color-md-highlight-active-bg: rgba(251, 191, 36, 0.6);
+  --color-md-highlight-active-outline: rgba(251, 191, 36, 0.7);
+  --color-md-welcome-btn: #4A6AE5;
+
  /* Borders */
  --color-border-subtle: rgba(255, 255, 255, 0.04);
  --color-border: rgba(255, 255, 255, 0.08);
@@ -116,6 +153,26 @@ html, body, #root {
  overflow: visible;
 }

+/* Skip link - WCAG 2.4.1 */
+.skip-link {
+  position: fixed;
+  top: -100%;
+  left: 16px;
+  z-index: 99999;
+  padding: 8px 16px;
+  background-color: var(--color-accent);
+  color: white;
+  font-size: 13px;
+  font-weight: 600;
+  border-radius: var(--radius-md);
+  text-decoration: none;
+  transition: top 0.2s ease;
+}
+
+.skip-link:focus {
+  top: 8px;
+}
+
 /* App container */
 .app-container {
  display: flex;
@@ -261,7 +318,7 @@ html, body, #root {
  color: var(--color-text-primary);
 }

-/* Menu backdrop — invisible overlay to catch outside clicks */
+/* Menu backdrop - invisible overlay to catch outside clicks */
 .menu-backdrop {
  position: fixed;
  top: 0;
@@ -354,8 +411,8 @@ html, body, #root {
  display: flex;
  align-items: center;
  justify-content: center;
-  width: 22px;
-  height: 22px;
+  width: 24px;
+  height: 24px;
  background: transparent;
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-sm);
@@ -403,14 +460,18 @@ html, body, #root {
  transition: all var(--transition-fast);
  opacity: 0;
  pointer-events: none;
+  visibility: hidden;
 }

 .tab-scroll-arrow.visible {
-  opacity: 1;
+  opacity: 0.6;
  pointer-events: auto;
+  visibility: visible;
 }

-.tab-scroll-arrow:hover {
+.tab-scroll-arrow.visible:hover,
+.tab-scroll-arrow.visible:focus-visible {
+  opacity: 1;
  color: var(--color-text-primary);
  background-color: var(--color-bg-hover);
 }
@@ -440,6 +501,7 @@ html, body, #root {
  padding: 0 12px;
  background: transparent;
  border: none;
+  border-bottom: 2px solid transparent;
  border-radius: var(--radius-md);
  color: var(--color-text-secondary);
  cursor: pointer;
@@ -457,6 +519,7 @@ html, body, #root {
 .tab.active {
  background-color: var(--color-bg-elevated);
  color: var(--color-text-primary);
+  border-bottom: 2px solid var(--color-accent);
 }

 .tab-title {
@@ -467,8 +530,8 @@ html, body, #root {
 }

 .tab-close {
-  width: 18px;
-  height: 18px;
+  width: 24px;
+  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
@@ -477,12 +540,13 @@ html, body, #root {
  border-radius: var(--radius-sm);
  color: var(--color-text-tertiary);
  cursor: pointer;
-  opacity: 0;
+  opacity: 0.5;
  flex-shrink: 0;
  transition: all var(--transition-fast);
 }

-.tab:hover .tab-close {
+.tab:hover .tab-close,
+.tab-close:focus-visible {
  opacity: 1;
 }

@@ -539,13 +603,14 @@ html, body, #root {
  right: 0;
  top: 0;
  bottom: 0;
-  width: 4px;
+  width: 8px;
+  background: rgba(255, 255, 255, 0.06);
  cursor: col-resize;
-  background: transparent;
  transition: background-color var(--transition-fast);
 }

-.sidebar-resize-handle:hover {
+.sidebar-resize-handle:hover,
+.sidebar-resize-handle:focus-visible {
  background-color: var(--color-accent);
 }

@@ -651,9 +716,11 @@ html, body, #root {
  color: var(--color-text-tertiary);
 }

-.search-input:focus {
+.search-input:focus-visible {
  border-color: var(--color-accent);
  background-color: var(--color-bg-base);
+  outline: 2px solid var(--color-accent);
+  outline-offset: -2px;
 }

 .search-results {
@@ -781,7 +848,7 @@ html, body, #root {

 .welcome-button {
  padding: 12px 28px;
-  background-color: #6B8AFF;
+  background-color: var(--color-md-welcome-btn);
  color: white;
  border: none;
  border-radius: 8px;
@@ -872,7 +939,7 @@ html, body, #root {
  z-index: 10003 !important;
 }

-/* Shortcuts dialog — uses its own class to avoid DaisyUI .modal conflicts */
+/* Shortcuts dialog - uses its own class to avoid DaisyUI .modal conflicts */
 .shortcuts-dialog {
  background-color: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
@@ -929,7 +996,7 @@ html, body, #root {
 .shortcuts-dialog-group-title {
  font-size: 11px;
  font-weight: 600;
-  color: var(--color-accent);
+  color: var(--color-accent-small);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 12px;
@@ -1106,6 +1173,8 @@ html, body, #root {
  max-width: 680px;
  margin: 0 auto;
  color: var(--color-text-primary);
+  overflow-wrap: break-word;
+  word-break: break-word;

  /* Premium typography settings */
  font-size: 17px;
@@ -1122,14 +1191,14 @@ html, body, #root {
  text-spacing-trim: trim-both;
 }

-/* Refined heading hierarchy — progressive color cascade */
+/* Refined heading hierarchy - progressive color cascade */
 .markdown-content h1,
 .markdown-content h2,
 .markdown-content h3,
 .markdown-content h4,
 .markdown-content h5,
 .markdown-content h6 {
-  color: #F0F1F3;
+  color: var(--color-md-heading);
  font-family: 'Inter Variable', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  font-weight: 600;
  line-height: 1.2;
@@ -1143,7 +1212,7 @@ html, body, #root {
  font-size: 2.35rem;
  font-weight: 700;
  letter-spacing: -0.03em;
-  color: #F5F6F7;
+  color: var(--color-md-h1);
  margin-top: 0;
  margin-bottom: 0.8em;
  padding-bottom: 0.55em;
@@ -1152,7 +1221,7 @@ html, body, #root {

 .markdown-content h2 {
  font-size: 1.7rem;
-  color: #EDEEF0;
+  color: var(--color-md-h2);
  margin-top: 1.85em;
  padding-bottom: 0.4em;
  border-bottom: 1px solid var(--color-border-subtle);
@@ -1160,47 +1229,47 @@ html, body, #root {

 .markdown-content h3 {
  font-size: 1.3rem;
-  color: #E4E5E8;
+  color: var(--color-md-h3);
 }

 .markdown-content h4 {
  font-size: 1.15rem;
  font-weight: 500;
-  color: #D8DADE;
+  color: var(--color-md-h4);
 }

 .markdown-content h5 {
  font-size: 1rem;
  font-weight: 500;
-  color: #CBCED3;
+  color: var(--color-md-h5);
 }

 .markdown-content h6 {
  font-size: 0.92rem;
  font-weight: 500;
-  color: #ABB0B8;
+  color: var(--color-md-h6);
 }

 /* Paragraphs with refined spacing */
 .markdown-content p {
  margin-bottom: 1.65em;
-  color: #C8CCD0;
+  color: var(--color-md-paragraph);
  line-height: 1.7;
 }

 /* Links with subtle persistent underline */
 .markdown-content a {
-  color: #7CA9F7;
+  color: var(--color-md-link);
  text-decoration: underline;
-  text-decoration-color: rgba(124, 169, 247, 0.3);
+  text-decoration-color: var(--color-md-link-underline);
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
  transition: color 0.2s ease, text-decoration-color 0.2s ease;
 }

 .markdown-content a:hover {
-  color: #93B8F9;
-  text-decoration-color: rgba(147, 184, 249, 0.7);
+  color: var(--color-md-link-hover);
+  text-decoration-color: var(--color-md-link-hover-underline);
  text-decoration-thickness: 1.5px;
 }

@@ -1233,13 +1302,13 @@ html, body, #root {

 .markdown-content li {
  margin-bottom: 0.45em;
-  color: #C8CCD0;
+  color: var(--color-md-paragraph);
  line-height: 1.65;
  list-style-position: outside;
 }

 .markdown-content li::marker {
-  color: #7CA9F7;
+  color: var(--color-md-marker);
 }

 .markdown-content ol li::marker {
@@ -1320,17 +1389,17 @@ html, body, #root {
 .markdown-content blockquote {
  margin: 1.65em 0;
  padding: 1.1em 1.4em;
-  border-left: 3px solid #7CA9F7;
-  background-color: rgba(124, 169, 247, 0.04);
+  border-left: 3px solid var(--color-md-blockquote-border);
+  background-color: var(--color-md-blockquote-bg);
  border-radius: 0 8px 8px 0;
-  color: #B0B4B9;
+  color: var(--color-md-blockquote-text);
  font-style: normal;
  line-height: 1.7;
 }

 .markdown-content blockquote p {
  margin-bottom: 0.5em;
-  color: #B0B4B9;
+  color: var(--color-md-blockquote-text);
 }

 .markdown-content blockquote p:last-child {
@@ -1339,26 +1408,26 @@ html, body, #root {

 /* Inline code */
 .markdown-content code:not(pre code) {
-  background-color: rgba(255, 255, 255, 0.06);
+  background-color: var(--color-md-code-inline-bg);
  padding: 0.22em 0.48em;
  border-radius: 5px;
  font-family: 'JetBrains Mono Variable', 'JetBrains Mono', 'SF Mono', 'Fira Code', monospace;
  font-size: 0.88em;
  font-weight: 400;
-  color: #E0A88A;
+  color: var(--color-md-code-inline);
  letter-spacing: -0.02em;
 }

 /* Code blocks */
 .markdown-content pre {
-  background-color: #1A1D24;
+  background-color: var(--color-md-code-block-bg);
  border-radius: 10px;
  padding: 1.35em 1.6em;
  margin: 1.65em 0;
  overflow-x: visible;
  overflow-wrap: break-word;
  white-space: pre-wrap;
-  border: 1px solid rgba(255, 255, 255, 0.06);
+  border: 1px solid var(--color-md-code-block-border);
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.15);
 }

@@ -1366,7 +1435,7 @@ html, body, #root {
  font-family: 'JetBrains Mono Variable', 'JetBrains Mono', 'SF Mono', 'Fira Code', monospace;
  font-size: 14px;
  line-height: 1.7;
-  color: #E4E6EB;
+  color: var(--color-md-code-text);
  background: none;
  padding: 0;
  letter-spacing: -0.02em;
@@ -1378,7 +1447,7 @@ html, body, #root {
 /* Syntax highlighting - refined colors */
 .hljs {
  background: transparent !important;
-  color: #E4E6EB;
+  color: var(--color-md-code-text);
 }

 .hljs-keyword,
@@ -1408,7 +1477,7 @@ html, body, #root {
 .hljs-quote,
 .hljs-deletion,
 .hljs-meta {
-  color: #5C6370;
+  color: var(--color-md-comment);
  font-style: italic;
 }

@@ -1442,7 +1511,7 @@ html, body, #root {
  font-size: 14px;
  border-radius: 10px;
  overflow: hidden;
-  border: 1px solid rgba(255, 255, 255, 0.06);
+  border: 1px solid var(--color-md-table-border);
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.1);
 }

@@ -1450,11 +1519,11 @@ html, body, #root {
 .markdown-content td {
  padding: 14px 18px;
  text-align: left;
-  border-bottom: 1px solid rgba(255, 255, 255, 0.04);
+  border-bottom: 1px solid var(--color-border-subtle);
 }

 .markdown-content th {
-  background-color: rgba(124, 169, 247, 0.08);
+  background-color: var(--color-md-table-header-bg);
  font-weight: 600;
  color: var(--color-text-primary);
  font-size: 12.5px;
@@ -1463,7 +1532,7 @@ html, body, #root {
 }

 .markdown-content td {
-  color: #C8CCD0;
+  color: var(--color-md-table-cell);
 }

 .markdown-content tr:last-child td {
@@ -1471,18 +1540,18 @@ html, body, #root {
 }

 .markdown-content tr:nth-child(even) td {
-  background-color: rgba(30, 33, 40, 0.4);
+  background-color: var(--color-md-table-stripe);
 }

 .markdown-content tr:hover td {
-  background-color: rgba(124, 169, 247, 0.05);
+  background-color: var(--color-md-table-hover);
 }

-/* Horizontal rule — gradient fade */
+/* Horizontal rule - gradient fade */
 .markdown-content hr {
  border: none;
  height: 1px;
-  background: linear-gradient(to right, transparent, rgba(255, 255, 255, 0.1), transparent);
+  background: linear-gradient(to right, transparent, var(--color-md-hr), transparent);
  margin: 2.5em 0;
 }

@@ -1525,8 +1594,8 @@ html, body, #root {

 /* Mark/highlight */
 .markdown-content mark {
-  background-color: rgba(251, 191, 36, 0.2);
-  color: #FBBF24;
+  background-color: var(--color-md-mark-bg);
+  color: var(--color-md-mark-text);
  padding: 0.18em 0.38em;
  border-radius: 4px;
  font-weight: 500;
@@ -1556,18 +1625,21 @@ html, body, #root {
  border-radius: 8px;
 }

-/* Search highlights — high specificity to override Tailwind reset */
+/* Search highlights - high specificity to override Tailwind reset */
 span.search-highlight {
-  background-color: rgba(251, 191, 36, 0.3) !important;
+  background-color: var(--color-md-highlight-bg) !important;
  color: inherit !important;
  border-radius: 2px;
  padding: 1px 0;
+  text-decoration: underline;
+  text-decoration-color: var(--color-md-mark-text);
+  text-underline-offset: 2px;
  transition: background-color 0.15s ease, outline-color 0.15s ease;
 }

 span.search-highlight.search-highlight-active {
-  background-color: rgba(251, 191, 36, 0.6) !important;
-  outline: 2px solid rgba(251, 191, 36, 0.7);
+  background-color: var(--color-md-highlight-active-bg) !important;
+  outline: 2px solid var(--color-md-highlight-active-outline);
  outline-offset: 1px;
 }

@@ -1591,6 +1663,141 @@ span.search-highlight.search-highlight-active {
  transition: background-color 0.2s ease, opacity 0.2s ease;
 }

+/* Global focus indicator - WCAG 2.4.7, 2.4.13 */
+button:focus-visible,
+a:focus-visible,
+input:focus-visible,
+[tabindex]:focus-visible,
+[role="tab"]:focus-visible,
+[role="menuitem"]:focus-visible,
+[role="separator"]:focus-visible {
+  outline: 2px solid var(--color-accent);
+  outline-offset: 2px;
+  z-index: 1;
+}
+
+/* ============================================
+   Light theme overrides - WCAG 1.4.8
+   ============================================ */
+.theme-light {
+  --color-bg-base: #F5F6F8;
+  --color-bg-surface: #EBEDF0;
+  --color-bg-elevated: #FFFFFF;
+  --color-bg-overlay: #FFFFFF;
+  --color-bg-hover: #E2E4E8;
+  --color-bg-active: #D5D8DD;
+
+  --color-text-primary: #1A1D24;
+  --color-text-secondary: #4A5060;
+  --color-text-tertiary: #6B7280;
+  --color-text-disabled: #9CA3AF;
+
+  --color-accent: #3B66E0;
+  --color-accent-hover: #2B52CC;
+  --color-accent-muted: rgba(59, 102, 224, 0.10);
+  --color-accent-subtle: rgba(59, 102, 224, 0.05);
+  --color-accent-small: #2B52CC;
+
+  --color-border-subtle: rgba(0, 0, 0, 0.06);
+  --color-border: rgba(0, 0, 0, 0.10);
+  --color-border-strong: rgba(0, 0, 0, 0.16);
+
+  /* Markdown typography - light variants */
+  --color-md-h1: #111318;
+  --color-md-h2: #1A1D24;
+  --color-md-h3: #252A31;
+  --color-md-h4: #333942;
+  --color-md-h5: #404754;
+  --color-md-h6: #4A5060;
+  --color-md-heading: #1A1D24;
+  --color-md-paragraph: #333942;
+  --color-md-link: #2B5BC2;
+  --color-md-link-underline: rgba(43, 91, 194, 0.3);
+  --color-md-link-hover: #1E4AAE;
+  --color-md-link-hover-underline: rgba(30, 74, 174, 0.5);
+  --color-md-marker: #3B66E0;
+  --color-md-blockquote-border: #3B66E0;
+  --color-md-blockquote-bg: rgba(59, 102, 224, 0.04);
+  --color-md-blockquote-text: #4A5060;
+  --color-md-code-inline: #B35C2A;
+  --color-md-code-inline-bg: rgba(0, 0, 0, 0.04);
+  --color-md-code-block-bg: #F0F1F3;
+  --color-md-code-block-border: rgba(0, 0, 0, 0.08);
+  --color-md-code-text: #1A1D24;
+  --color-md-table-header-bg: rgba(59, 102, 224, 0.06);
+  --color-md-table-border: rgba(0, 0, 0, 0.08);
+  --color-md-table-cell: #333942;
+  --color-md-table-stripe: rgba(0, 0, 0, 0.02);
+  --color-md-table-hover: rgba(59, 102, 224, 0.04);
+  --color-md-hr: rgba(0, 0, 0, 0.1);
+  --color-md-mark-bg: rgba(251, 191, 36, 0.25);
+  --color-md-mark-text: #92650B;
+  --color-md-comment: #6B7280;
+  --color-md-highlight-bg: rgba(251, 191, 36, 0.3);
+  --color-md-highlight-active-bg: rgba(251, 191, 36, 0.5);
+  --color-md-highlight-active-outline: rgba(200, 150, 20, 0.7);
+  --color-md-welcome-btn: #3B66E0;
+}
+
+/* Light theme - noise overlay should be darker */
+.theme-light.app-container::before {
+  opacity: 0.025;
+  mix-blend-mode: multiply;
+}
+
+/* Light theme - title bar close button */
+.theme-light .title-bar-button.close:hover {
+  background-color: #DC2626;
+  color: white;
+}
+
+/* Light theme - scrollbar colors */
+.theme-light .os-theme-dark {
+  --os-handle-bg: rgba(0, 0, 0, 0.15);
+  --os-handle-bg-hover: var(--color-accent);
+  --os-handle-bg-active: var(--color-accent-hover);
+}
+
+/* Light theme - sidebar resize handle */
+.theme-light .sidebar-resize-handle {
+  background: rgba(0, 0, 0, 0.06);
+}
+
+.theme-light .sidebar-resize-handle:hover,
+.theme-light .sidebar-resize-handle:focus-visible {
+  background-color: var(--color-accent);
+}
+
+/* Light theme syntax highlighting */
+.theme-light .hljs { color: #1A1D24; }
+.theme-light .hljs-keyword,
+.theme-light .hljs-selector-tag,
+.theme-light .hljs-literal,
+.theme-light .hljs-section,
+.theme-light .hljs-link { color: #7C3AED; font-weight: 500; }
+
+.theme-light .hljs-string,
+.theme-light .hljs-title,
+.theme-light .hljs-name,
+.theme-light .hljs-type,
+.theme-light .hljs-attribute,
+.theme-light .hljs-symbol,
+.theme-light .hljs-bullet,
+.theme-light .hljs-addition,
+.theme-light .hljs-variable,
+.theme-light .hljs-template-tag,
+.theme-light .hljs-template-variable { color: #16652B; }
+
+.theme-light .hljs-comment,
+.theme-light .hljs-quote,
+.theme-light .hljs-deletion,
+.theme-light .hljs-meta { color: var(--color-md-comment); font-style: italic; }
+
+.theme-light .hljs-number { color: #C2410C; font-weight: 500; }
+.theme-light .hljs-built_in { color: #2563EB; }
+.theme-light .hljs-class .hljs-title { color: #B45309; }
+.theme-light .hljs-attr { color: #B45309; }
+
 /* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *,
--- a/test-markdown.md
+++ b/test-markdown.md
@@ -1,332 +0,0 @@
-# Markdown Combinations Test
-
-This file tests all possible combinations of markdown elements.
-
---
-
-## 1. Lists with Text Formatting
-
-### Bold in List
-
- **Bold item 1**
- **Bold item 2** with more text
- **Bold item 3** and *italic* and `code`
-
-### Italic in List
-
- *Italic item 1*
- *Italic item 2* with text
- *Italic* and **bold** together
-
-### Code in List
-
- `inline code` item
- Code with `const x = 1` variable
- Command `npm install`
-
-### Mixed Formatting in List
-
- **Bold** and *italic* and `code` all together
- ***Bold italic*** with normal text
- ~~Strikethrough~~ and **bold**
- ==Highlighted== and *italic*
-
---
-
-## 2. Headings in Lists
-
- ### Heading 3 in list
- #### Heading 4 in list
- ##### Heading 5 in list
-
-1. ### Heading 3 in ordered list
-2. #### Heading 4 in ordered list
-3. ##### Heading 5 in ordered list
-
---
-
-## 3. Blockquotes with Lists
-
-> ### Blockquote with list:
-> - Item 1
-> - Item 2
-> - Item 3
-
-> **Bold blockquote** with list:
-> 1. First
-> 2. Second
-> 3. Third
-
-> *Italic blockquote* with `code`:
-> - Item with `inline code`
-> - Another with **bold**
-
---
-
-## 4. Lists in Blockquotes
-
-> This is a blockquote with a nested list:
-> - First level
->   - Second level
->     - Third level
->       - Fourth level
-> - Back to first
-
-> Another blockquote with mixed content:
-> - **Bold item**
-> - *Italic item*
-> - `Code item`
-> - [Link item](https://example.com)
-
---
-
-## 5. Links in Various Elements
-
-### Links in Lists
-
- [Link](https://example.com) in list
- [Link with title](https://example.com "Title") in list
- [Reference link][ref] in list
-
-[ref]: https://example.com
-
-### Links in Blockquotes
-
-> [Link in blockquote](https://example.com)
-> **[Bold link](https://example.com)**
-> *[[Italic link](https://example.com)*
-
-### Links in Code
-
- `<a href="https://example.com">Link</a>` in list
- `[link](url)` as code
-
---
-
-## 6. Images in Various Elements
-
-### Images in Lists
-
- ![Image](https://via.placeholder.com/100x50.png) in list
- ![Alt text](https://via.placeholder.com/100x50.png "Image title")
-
-### Images in Blockquotes
-
-> ![Image in blockquote](https://via.placeholder.com/100x50.png)
-
---
-
-## 7. Code Blocks with Formatting
-
-### Code Block with Bold/Italic
-
-```
-**This is bold in code**
-*This is italic in code*
-`inline code in code block`
-```
-
-### Code Block Inside List
-
- ```
-  // Code block in list
-  const x = 1;
-  ```
- Another item
-
---
-
-## 8. Tables with Formatting
-
-| Header | **Bold Header** | *Italic Header* |
-|--------|-----------------|-----------------|
-| Cell | **Bold Cell** | *Italic Cell* |
-| `Code` | **Bold** + `code` | *Italic* + `code` |
-
---
-
-## 9. Nested Lists with All Formatting
-
- Level 1 **bold**
-  - Level 2 *italic*
-    - Level 3 `code`
-      - Level 4 ~~strikethrough~~
-        - Level 5 ==highlight==
-
-1. Ordered 1 **bold**
-   1. Ordered 1.1 *italic*
-      1. Ordered 1.1.1 `code`
-
---
-
-## 10. Complex Combinations
-
-### Blockquote > List > Blockquote
-
-> - Item 1
->   > Nested blockquote
->   > With **bold**
-> - Item 2
-
-### List > Blockquote > List
-
- Item 1
-  > Blockquote inside list
-  > With *italic*
- Item 2
-
-### List > Code > List
-
- Item 1
-  ```
-  // Code block nested
-  const x = 1;
-  ```
- Item 2
-
-### Task List with Formatting
-
- [x] **Completed** task with *italic*
- [ ] *Incomplete* with `code`
- [x] ==Highlighted== and **bold** and *italic*
-
---
-
-## 11. Heading + List Combinations
-
-### Heading followed by formatted list
-
-#### Subheading
-
- **Bold item**
- *Italic item*
- `Code item`
-
-### Multiple headings in sequence
-
-## Section 1
-
- Item 1
- Item 2
-
-## Section 2
-
-1. Ordered 1
-2. Ordered 2
-
-### Heading within list (edge case)
-
- Normal item
- #### Not a heading (just text)
- Normal item
-
---
-
-## 12. Links + Code + Bold + Italic combinations
-
- **[Bold link](https://example.com)**
- *[Italic link](https://example.com)*
- [`Code link`](https://example.com)
- **[Link](https://example.com)** with `code` and *italic*
- ***[All combined](https://example.com)*** with `more code`
-
---
-
-## 13. Tables + Lists combinations
-
-| Table | With | Formatting |
-|-------|------|-----------|
-| - List in table | - Another | - Item |
-| **Bold** | *Italic* | `Code` |
-
- Table below list:
-
-| Col1 | Col2 |
-|------|------|
-| A    | B    |
-
- List below table:
-
-  | Col1 | Col2 |
-  |------|------|
-  | C    | D    |
-
---
-
-## 14. All Elements in One Paragraph
-
-This is a paragraph with **bold**, *italic*, ***bold italic***, `inline code`, [a link](https://example.com), ![an image](https://via.placeholder.com/50x20.png), ~~strikethrough~~, ==highlight==, and ^superscript^, all in one paragraph. It's quite long and should test how your renderer handles multiple formatting elements combined.
-
---
-
-## 15. Edge Case: Empty Elements
-
- 
- Item after empty
-
->
-> Empty blockquote
-
---
-
-## 16. Deep Nesting
-
-1. Level 1
-   - Level 2
-     - Level 3
-       - Level 4
-         - Level 5
-           - Level 6
-             - **Deep bold**
-             - *Deep italic*
-             - `Deep code`
-
---
-
-## 17. Code Blocks with Language and Formatting
-
-```javascript
-// JavaScript with **fake bold** (just text)
-const greet = (name) => {
-  return `Hello, ${name}!`; // Template literal
-};
-```
-
-```python
-# Python with *italic* comments
-def hello():
-    """Docstring with **bold**"""
-    return "Hello"
-```
-
-```html
-<!-- HTML comment with **bold** -->
-<div class="container">
-  <p>Paragraph with *italic*</p>
-</div>
-```
-
---
-
-## 18. Final Complex Example
-
-> ### Blockquote Heading
-> 
-> This is a blockquote that contains:
-> 
-> - A **bold** list item
-> - An *italic* list item  
-> - A `code` list item
-> - A [link](https://example.com) item
-> 
-> And then continues with more text that has **bold**, *italic*, and `code` formatting.
-> 
-> It also has a nested list:
-> 
-> 1. First nested **bold** item
-> 2. Second nested *italic* item
-> 3. Third nested `code` item
-
---
-
-This covers virtually every possible combination of markdown elements!
Author	SHA1	Message	Date
Your Name	223ce2e56a	Clean up special characters in source files	2026-02-19 22:11:04 +02:00
Your Name	bb0f0d30da	Update Cargo.lock for v1.1.0	2026-02-19 22:06:21 +02:00
Your Name	ef8a4524b9	Bump version to 1.1.0 and update README Add accessibility section documenting WCAG 2.2 AAA compliance, keyboard navigation, focus management, and theme support. Update file handling with single-instance and OS association. Fix repo URLs and version badge.	2026-02-19 22:02:21 +02:00
Your Name	5af64df152	Fix duplicate tabs on drag-and-drop and long URL overflow Guard against Windows/WebView2 firing duplicate drop events by tracking in-progress paths with a Set ref. Add overflow-wrap and word-break to markdown content so long unbroken strings wrap.	2026-02-19 22:00:51 +02:00
Your Name	766f0f94f2	Add single-instance support and clean up scaffolding files Ensure only one Vesper instance runs at a time. When a second instance is launched with a file argument, the file is forwarded to the existing window. Remove unused template SVGs and test file.	2026-02-19 22:00:43 +02:00
Your Name	a5c168ee9d	fix: upgrade to pointer events for cancellation support, final a11y cleanup	2026-02-19 21:42:30 +02:00
Your Name	37cf83dd5c	feat: add light theme with full WCAG AAA contrast compliance	2026-02-19 21:41:04 +02:00
Your Name	e8f523ad05	feat: add Content Zoom and Content Width controls to View menu	2026-02-19 21:38:29 +02:00
Your Name	f2ad745c28	fix: add non-color indicators for active tab and search highlights	2026-02-19 21:37:51 +02:00
Your Name	88964ec842	feat: highlight active heading in sidebar table of contents	2026-02-19 21:36:59 +02:00
Your Name	969aff1e25	feat: respect prefers-reduced-motion for Framer Motion animations	2026-02-19 21:35:22 +02:00
Your Name	204757bf6a	feat: add focus trap to modal dialogs	2026-02-19 21:33:39 +02:00
Your Name	59b047ff25	feat: add Shift+F10 context menu trigger and keyboard navigation	2026-02-19 21:31:56 +02:00
Your Name	e7544c283e	feat: add keyboard navigation for sidebar and resize handle	2026-02-19 21:29:11 +02:00
Your Name	2e0741760f	feat: add keyboard navigation for tab bar	2026-02-19 21:27:24 +02:00
Your Name	7031accf17	feat: add full keyboard navigation for menu bar	2026-02-19 21:24:47 +02:00
Your Name	86d25a5823	fix: add ARIA roles, labels, and states to all interactive components	2026-02-19 21:20:27 +02:00
Your Name	f550dba3b9	fix: add skip link and semantic HTML landmarks	2026-02-19 21:16:58 +02:00
Your Name	ecb9fd867c	fix: add focus indicators, fix target sizes, show hidden controls	2026-02-19 21:15:03 +02:00
Your Name	c644d7372d	refactor: extract markdown typography colors into CSS variables	2026-02-19 21:13:07 +02:00
Your Name	ecde5d7f88	fix: update color contrast to meet WCAG 2.2 AAA requirements	2026-02-19 21:08:29 +02:00
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