Two upgrades: a real library and a lesson-aware playground

The curriculum crossed fifty lessons, and at that size two rough edges started to matter: finding the right concept, and doing something with its code. Both just got a lot better.

A library you can actually filter

There's now a Library — every concept in one searchable grid. Filter by track, by difficulty, or by topic; the topic tags compose, so you can pull up everything tagged accessibility or performance at once. Search runs over titles, summaries, and tags together.

The part we're happiest with is quieter: you can mark lessons as read and save them for later, and then filter the library down to just your unread or saved set. The tracks map fills in a progress bar per track as you go.

All of that is stored only in your browser. It is never sent to a server, never logged, and never used as a data source — and you can erase every bit of it with one button in Settings. Personalization shouldn't cost you your privacy.

A playground that understands lessons

The playground was always one click from any code block. Now it can take an entire lesson at once. The new Open all snippets in the playground button on each lesson collects every runnable example — the CSS, the component, the markup — and drops them into a single multi-file sandbox you can browse and remix as separate files.

Under the hood, the handoff figures out the right project shape: React snippets become components that auto-render, CSS merges into a stylesheet the preview actually applies, and HTML-or-CSS-only lessons become a static page. The point is to make experimentation frictionless — change one thing, see what breaks, build the intuition the code alone won't give you.

What's next

Guides and this blog are new too (you're reading the proof). Next up: showcases for sharing more work, and richer media. As always, it's open — build it, copy it, ship it.