Cairn

A mind map built for one specific job: helping you talk through something live — an interview, a presentation, a call — without losing your train of thought. Branch out your topics, click through them to stay oriented, and keep your talking points one click away without turning your screen into a wall of text.

No install, no build, no account. It's three files and runs entirely in your browser, offline, with everything saved locally on your machine.

Try it live: https://severodeveloper.github.io/cairn/

Getting started

Open the live version above, or run it locally by opening index.html in a browser — no server needed. Your map autosaves to that browser's local storage as you go, so closing the tab and coming back later picks up right where you left off.

The two modes

The pencil/presentation icon in the top-right switches between them:

• Editing — build out your map: add branches, rename them, write notes, delete, drag branches around.
• Presenting — a clean view for when you're actually live. No add/delete/rename controls, notes open as plain read-only text instead of an editor. Everything else (clicking, centering, notes) still works.

Building your map

• Add a branch — hover a node and click the + icon. New branches focus and open for renaming immediately.
• Rename — double-click a node's title.
• Delete a branch — hover a node, click the trash icon in the corner (this also deletes everything under it).
• Move a branch elsewhere — drag it and drop it onto another node to reconnect it there. A dashed line follows your cursor while dragging, and a valid drop target lights up blue. You can't drop a branch onto itself or onto one of its own children (Editing mode only).
• Notes — right-click any node to open its notes. In Editing mode this opens the full editor; in Presenting mode it opens a read-only view (only if that node actually has notes).
  • Ctrl+B — bold
  • Ctrl+H — toggle a highlight on the selected text
  • Start a line with "- " — turns it into a bullet, same as Docs/Notion
  • Click outside the editor, hit Escape, or click Done to save. Cancel discards.
• Notes previews — the eye icon in the header shows/hides a short preview of each node's notes directly on the map. When previews are off, nodes that have notes still show a small icon so you know they're there.

Getting around

• Left-click a branch — highlights its full path back to the root and centers it on screen.
• Click empty space (or Escape) — fits the whole map back into view.
• Drag empty space — pan around.
• Scroll — zoom in/out, centered on your cursor.

Every top-level branch gets its own color, shared by everything underneath it, so you can tell branches apart across the whole map at a glance — not just the one you're currently focused on.

Backing up your map

⚠️ Your map lives only in this browser's local storage. There's no account, no server, no sync — which also means there's no recovery if it's gone. Clearing browser data, using a private/incognito window, switching browsers or devices, or the browser evicting storage under low disk space will all wipe it permanently. If a map matters, export it.

The ⋮ menu in the header has:

• Export map — downloads your current map as a .json file.
• Import map — loads a map from a .json file (replaces what's currently open — it'll ask you to confirm first).
• New map — clears everything and starts over with a single blank node titled "Start."

Notes on offline use

Everything — the map engine, storage, and icons — is vendored locally, so once you have the files there's no network dependency at all.

Want the technical details?

See ARCHITECTURE.md for how the layout, rendering, drag interactions, and text editor actually work under the hood.