30 checks in Technical Foundation & Rendering. Automated Its subsection has a live automated checker in the engine.
| ID | Check | Passes when |
|---|---|---|
| 1.6.01 | Identify render-blocking CSS resources in <head> | Minimized |
| 1.6.02 | Validate critical CSS is inlined or preloaded | Present |
| 1.6.03 | Measure total CSS blocking time (ms) | < 200ms |
| 1.6.04 | Validate no external CSS blocks first paint | Non-blocking |
| 1.6.05 | Detect unused CSS percentage on homepage | < 40% unused |
| 1.6.06 | Detect unused CSS percentage on key service pages | < 40% unused |
| 1.6.07 | Measure CLS score on homepage (mobile) | < 0.1 |
| 1.6.08 | Measure CLS score on homepage (desktop) | < 0.1 |
| 1.6.09 | Identify elements contributing most to CLS | Documented |
| 1.6.10 | Validate images have explicit width/height or aspect-ratio | Present |
| 1.6.11 | Validate ads/embeds have reserved space | Reserved |
| 1.6.12 | Validate web fonts have font-display: swap or optional | Present |
| 1.6.13 | Validate no FOIT (Flash of Invisible Text) on load | No FOIT |
| 1.6.14 | Validate no FOUT (Flash of Unstyled Text) persists > 500ms | Minimal |
| 1.6.15 | Validate dynamic content injection does not trigger layout shift | Stable |
| 1.6.16 | Validate lazy-loaded content has placeholder dimensions | Reserved |
| 1.6.17 | Validate sticky/fixed elements do not shift surrounding layout | Stable |
| 1.6.18 | Validate CSS @import chains do not exceed 2 levels | <= 2 |
| 1.6.19 | Validate CSS is minified in production | Minified |
| 1.6.20 | Validate CSS source maps not exposed in production | Not exposed |
| 1.6.21 | Validate above-the-fold content renders without any external CSS | Functional |
| 1.6.22 | Validate media queries do not cause layout reflow on resize | Stable |
| 1.6.23 | Validate CSS custom properties do not cause FOUC | Clean |
| 1.6.24 | Detect CSS resources loaded from third-party domains | Minimized |
| 1.6.25 | Validate third-party CSS has SRI integrity hash | Present |
| 1.6.26 | Validate total CSS payload size < 100KB (compressed) | Under limit |
| 1.6.27 | Validate CSS delivery uses HTTP/2+ multiplexing | Enabled |
| 1.6.28 | Validate preload hints for critical CSS files | Present |
| 1.6.29 | Validate no duplicate CSS rules across stylesheets | Minimal duplication |
| 1.6.30 | Compute CSS Blocking & CLS Risk Score | Finalized |
← 1.5 Redirect Graph Flattening Suite1.7 Critical Rendering Path Optimization Suite →
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See plansMachine-readable: catalog totals and the full catalog as JSON (IDs, section, weight, status).