Changing how a video looks by playback or mute state has meant syncing CSS classes from JavaScript events. Media state pseudo-classes let CSS select browser-managed states directly. This article covers all seven, plus :has().

With flex-wrap: wrap, the last line often holds just a few items, leaving the lines badly unbalanced. flex-wrap: balance keeps the line count that normal wrapping produces while redistributing flex items so each line comes out about the same length.

Zod 4.5 adds z.compile(), which turns a schema into JavaScript optimized at runtime. A compiled schema keeps the same API as a regular schema while validating complex data faster. This article covers the basics and how it works.

Shapes built with clip-path's path() are hard to make responsive because its coordinates are fixed pixels. shape() defines curves with percentages, CSS units, and custom properties. This article builds a resizable speech bubble and a motion path.

Chrome DevTools sends GET /.well-known/appspecific/com.chrome.devtools.json to detect your local project as a Workspace. This article covers why the 404 is harmless, what returning JSON enables, security notes, and support in Vite and Next.js.

ChatGPT desktop's built-in browser now supports WebMCP, which lets a website expose its features as tools for AI agents. We build a WebMCP-enabled TODO app and inspect the arguments and results of the Site tools Codex calls from its execution history.

IndexedDB is an asynchronous, transactional database for storing structured data in the browser. Learn its fundamentals through the native API, then build a task management app with React and Dexie.js.

Forgetting to restore a spy in Vitest lets mock state leak into other tests. Since Vitest 3.2.0, assigning the return value of `vi.spyOn()` to a `using` declaration restores the original implementation automatically when the scope exits.

I thought AI-written articles were too generic and too wordy, so I only used AI to catch typos. Trying a workflow that hands drafting to AI, I found that reading the draft critically and adding my own experience preserves most of the learning.

Slack Code brings open, team-wide development into Slack. Instead of DMs and threads, you create a special channel called a code channel and work with a coding agent as a whole team. Here is what it was like to actually try it out.

Adding thousands of elements to the DOM at once drives up rendering and update costs. TanStack Virtual is a headless library that renders only the items needed for the current scroll position. This article covers virtualizing a list in React.

ARIA roles alone do not make a Tree View accessible. Learn to build a single-select Tree View in React with roving tabindex, arrow-key navigation, selection, and type-ahead, following the WAI-ARIA APG.