fxcss catalogue

fxcss catalogue --open

Builds an HTML directory of the UI parts a theme can target. For each one: a cropped screenshot of the real element in light and dark, its selector, the styles in effect, and every rule in your theme that targets it. Plus an annotated overview screenshot with each part numbered.

Everything is measured from a running browser rather than hardcoded, so it stays honest as Firefox changes — an element that no longer exists is reported as missing rather than quietly documented.

Add --self-contained to also get a single catalogue.html with the images inlined, for attaching to an issue.