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Guides CSS rendering and layout performance tests for component UIs. Use when checking selector cost, layout thrash, paint work, animation smoothness, CSS containment, computed styles, or visual regressions caused by CSS changes.
Guides browser-based performance testing for HTML, CSS, JavaScript, and UI interactions. Use when measuring frontend performance, adding Playwright perf tests, checking regressions, profiling load/render/interaction cost, or discussing performance budgets.
Guides JavaScript runtime performance testing for frontend components. Use when profiling event handlers, DOM update loops, memory leaks, timers, animation frames, pointer/keyboard interactions, or regressions in vanilla JS component code.
Guides performance testing for native Web Components and custom elements. Use when measuring custom element registration, upgrade cost, connected/disconnected callbacks, attributeChangedCallback churn, Shadow DOM work, slots, or fig-* component scalability.
Guides accessibility review and implementation for FigUI3 web components and playground examples. Use when the user mentions accessibility, a11y, ARIA, screen readers, keyboard navigation, focus rings, labels, roles, disabled states, contrast, dialogs, menus, or form control semantics.
Guides CSS and layout tests for FigUI3 components. Use when validating component CSS, nested selectors, tokens, interaction states, computed styles, layout boxes, or visual regressions.
Guides real-browser tests for FigUI3 custom elements. Use when adding or debugging tests for fig-* web components, attribute/property contracts, value synchronization, event payloads, disabled behavior, or custom element registration.
| name | css-render-performance |
| description | Guides CSS rendering and layout performance tests for component UIs. Use when checking selector cost, layout thrash, paint work, animation smoothness, CSS containment, computed styles, or visual regressions caused by CSS changes. |
Test CSS performance in a browser with real stylesheets loaded. Pair this with css-component-testing when the risk is both correctness and render cost.
getBoundingClientRect or computed styles.requestAnimationFrame to separate write, style/layout flush, and visual completion.performance.now() for scoped timings.requestAnimationFrame for frame-boundary checks.getComputedStyle for resolved token/state assertions.getBoundingClientRect for layout cost and final geometry.PerformanceObserver for long tasks when supported by the browser under test.contain or content-visibility only when it preserves layout, accessibility, and interaction behavior.