Lumina: Web & PDF Highlighter de Khushwant Singh

Lumina is a local-first highlighter and note-taking extension for web pages and PDFs. Select text, pick a color, and attach a note. Everything stays on your device in IndexedDB. No account, no cloud, no tracking.

WHY LUMINA
• Works the same on web pages and PDFs — one tool for the whole web.
• Five highlight colors plus a screen-reader-friendly colour label on every highlight (the <mark> element carries an aria-label like "Highlighted in yellow: <excerpt>") so colourblind and AT users get the colour dimension even when the visual overlay alone isn't enough.
• Markdown notes on every highlight (bold, italic, inline code).
• Sidebar with full-text search, export, import, and one-click clear.
• Keyboard shortcuts for power users.
• 100% local storage. Your highlights never leave your browser.

WEB PAGE HIGHLIGHTING
• Highlight any selection on any site with five colors: yellow, green, blue, pink, orange.
• Hover a highlight to see its note in a tooltip.
• Click a highlight to change color, edit the note, or delete it.
• Robust anchoring: highlights survive page re-renders, SPA navigation, and lazy-loaded content thanks to a three-part anchor chain (text position, text quote with ±32-character context, and a CSS-selector fallback).
• Built for modern JavaScript apps — a mutation observer re-restores highlights when new content appears.

PDF HIGHLIGHTING
• PDFs open in a bundled Lumina viewer (Mozilla's PDF.js). No external requests for viewer code.
• Select text inside any PDF and highlight it with the same five-color palette.
• Highlights are anchored to the page offset and a text-quote fallback, so they reappear when you reopen the document. Anchors Lumina cannot resolve are surfaced as "orphaned" rather than silently dropped.
• Sidebar shows a "Page N" badge on every PDF entry and a jump-to-page action that reopens the PDF scrolled to the highlight.
• Works on https://, http://, and file:// PDFs. Local file:// PDFs require file-scheme access granted via about:addons → Lumina → Permissions → "Access your data for all websites" / file-URL toggle.

NOTES AND ANNOTATIONS
• Attach a markdown note to any highlight.
• Inline formatting: bold, italic, code. Unpaired markers render as literal characters so prose like "5 * 3 = 15" is preserved.
• Edit or delete notes from the in-page editor or the sidebar.

SIDEBAR
• Two views, one toggle: "This page" lists highlights on your current tab; "All" groups every highlight you've ever made by document, sorted by most recently visited, so you can revisit a passage you saved weeks ago without remembering which tab you were on.
• Full-text search across quotes, notes, and document titles.
• Export your library as JSON, import from a backup, or clear everything with a guarded confirmation. Imports offer Replace or Merge modes.
• Click any entry to scroll the page to that highlight. PDF entries scroll the bundled viewer to the page first; a brief "Loading page…" toast appears if the render takes more than a second.
• Theme (system / light / dark) and view mode are persisted across sessions.
• Opens from the sidebar launcher in the Firefox toolbar (the panel icon), or from View → Sidebar → Lumina.

KEYBOARD SHORTCUTS
• Ctrl + Shift + H — highlight the current selection with your last-used color.
• Ctrl + Shift + L — open the Lumina sidebar.
• If another extension or Firefox command has claimed these combos, rebind them via about:addons → Lumina → … menu → "Manage Extension Shortcuts".

PRIVACY
Lumina runs entirely on your device. Highlights, notes, color choices, and settings are stored in IndexedDB (plus a handful of settings keys in browser.storage.local) and never leave your browser. There are no analytics, telemetry pings, login screens, or third-party APIs. You can export your data any time and delete it any time.

PERMISSIONS EXPLAINED
• activeTab, tabs — to inject the highlighter into the page you are reading, and to focus the existing Lumina PDF viewer tab when you click a highlight in the sidebar (no duplicate tab).
• storage — to remember your last-used color, theme, and view-mode choice across sessions.
• webNavigation — to detect PDF navigations and redirect them to Lumina's bundled viewer (Firefox's built-in PDF viewer does not expose a text layer that extensions can read for highlighting).
• host_permissions <all_urls> — so highlighting works on every site you visit. Lumina makes no network requests of its own.