P1 Markdown render
P2 Code render + copy
P3 HTML sandbox (Option A: sandbox="allow-scripts" + srcdoc)
Isolation: iframe has no allow-same-origin, so embedded scripts cannot reach this page or its storage. Fixed 360px height in v1; auto-resize via postMessage deferred.
P4 React / JSX limits
v1 has no bundler and adds no dependency. Paste JSX to see the documented limit; precompiled HTML goes through the P3 sandbox above.
P5 Export · P6 Share · P7 Mobile · P8 Brand
Share encodes all four inputs into the URL hash locally; no server store in v1. Layout collapses to one column at 800px; usable at 375px. Brand: Montserrat, dark ground #111111, single Tangerine #F08000 accent. Markdown links allow http/https/mailto/# only.