What problem does it solve? Front-end code written by different contributors often drifts into inconsistent formatting, invalid markup, and inaccessible patterns. This Skill gives an agent a single authoritative checklist of Google's HTML/CSS conventions so code is written and reviewed against one consistent standard. ## Core Features & Use Cases - HTML authoring rules: Enforces valid HTML5, <!doctype html>, semantic elements, UTF-8 encoding, HTTPS resource URLs, multimedia fallback text, and separation of structure from presentation and behavior. - CSS authoring rules: Covers class naming conventions, selector discipline (no ID selectors, no type-qualified classes), shorthand properties, declaration formatting, and avoiding !important and CSS hacks. - Review guidance: Use it during code review to flag trailing whitespace, missing alt attributes, entity references, unnecessary type attributes, and formatting violations. - Use Case: While reviewing a pull request that adds a new landing page, the agent checks the markup against the guide and flags an id-based CSS selector, a missing alt attribute on an image, and a type="text/css" attribute that should be omitted. ## Quick Start Review the HTML and CSS in this change against the Google HTML/CSS style guide and list any violations.
