Hey, thanks for this project!
The only thing I felt was missing was the ability to zoom in/out, especially useful for screen sharing. I've never written anything for MacOS (neither objective C nor Swift) so this was mostly vibe coded but, at the end, I think it came out fine.

Merged - thank you for an excellent contribution!

This is one of the best-prepared PRs this repo has received. A few things that stood out during review:

• fontScale threaded through the parser -> renderer pipeline with dual-scope attributes, exactly how the codebase needs it
• per-tab routing via FocusedValue, so zooming one tab leaves the others alone
• the renderedFontScale split that keeps headings and body text resizing in a single visual step
• the Task.isCancelled guards, which also fix a pre-existing race where a superseded parse could land last
• tests covering both style scopes and the zoom ladder clamping

I verified it hands-on (including plain Cmd+= without Shift, which correctly triggers Bigger) and ran the full test suite - all green. One tiny follow-up landed on main after the merge: the README shortcuts row now also mentions Cmd+0 / Actual Size.

This will ship in the next release. Thanks again!

Glad you liked it, I have a couple more I'll push soon :)

v1.7.0 with this change is now live: https://github.com/b451c/quickmd/releases/tag/v1.7.0 - thanks again!