Review CSS loading that delays a page’s first visible content. Help inline essential styles and defer other stylesheets, using preload and media conditions, while checking rendered layouts at different screen widths and interaction states.
Use when reviewing stylesheets, component styles, and responsive behavior related to Load CSS without blocking render. Check the rendered layout across breakpoints and interaction states before proposing a fix.
Review the instructions the agent will receive before you install.
Render-blocking CSS delays First Contentful Paint—users see a blank screen while waiting for stylesheets to download and parse.
<link rel="preload" as="style"> with onload handlerAnalyze this CSS loading implementation to ensure stylesheets are loaded without blocking the DOM parsing and rendering process.
Implement non-blocking CSS loading using the preload technique with media attributes and loadCSS polyfill for better performance.
Explain how non-blocking CSS loading improves page performance by preventing render-blocking resources from delaying the initial paint.
Review stylesheets, component styles, and responsive states related to Load CSS without blocking render. Flag exact selectors, declarations, or breakpoints that violate the rule in the rendered UI.
For full implementation details, code examples, and framework-specific guidance,
see references/rule.md.
Rule page: https://frontendchecklist.io/rules/css/css-non-blocking
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Create and review custom 404 pages that help visitors recover from broken or moved links through search and navigation. Check the rendered page and HTTP response so missing content returns a proper 404 status.
Audit or create a dedicated About page that explains a website’s purpose and identifies its people or organization. Review the rendered output and supporting information, including expertise and contact details, to find gaps.
Review and add automated accessibility checks for components, pages, and continuous integration workflows. Use axe-based tools to detect structural and attribute issues, while identifying checks that still need keyboard or screen reader testing.
Review sign-in, registration, multi-factor authentication, and account recovery for accessibility barriers. Find blocked paste, difficult code entry, and inaccessible backup methods, then suggest authentication paths that support password managers, autofill, or device approval.
Review form errors, success messages, and live updates so screen reader users receive important notifications. Check the HTML delivered to the browser, announcement settings, display duration, and dismissal controls, then identify specific elements that need changes.
Review HTML tables so screen reader users can understand how headers and data relate. Check header markup, table descriptions, and merged cells, then identify specific fixes and ways to verify them.