We present a large-scale automated audit of WCAG 2.1/2.2 Level AA colour contrast compliance across the 500 most frequently crawled registered domains in Common Crawl's CC-MAIN-2026-08 February 2026 crawl archive. Rather than conducting a live crawl, all page content was sourced from Common Crawl's open WARC archives, ensuring reproducibility and eliminating any load on target web servers. Our static CSS analysis of 240 homepages identified 4,327 unique foreground/background colour pairings, of which 1,771 (40.9%) failed to meet the 4.5:1 contrast ratio threshold for normal text. The median per-site pass rate was 62.7%, with 20.4% of sites achieving full compliance across all detected colour pairings. These findings suggest that colour contrast remains a widespread accessibility barrier on the most prominent websites, with significant variation across domain categories.

翻译：本研究对Common Crawl在2026年2月发布的CC-MAIN-2026-08爬取档案中，访问频率最高的500个注册域名进行了大规模自动化审计，评估其是否符合WCAG 2.1/2.2 AA级别的色彩对比度标准。所有页面内容均来源于Common Crawl开放的WARC档案库，而非实时爬取，这确保了研究的可复现性，同时避免对目标网站服务器造成负载。通过对240个首页进行静态CSS分析，共识别出4,327组独立的前景/背景色彩配对，其中1,771组（占比40.9%）未达到常规文本所需的4.5:1对比度阈值。各网站合规比例的中位数为62.7%，仅20.4%的网站在所有检测到的色彩配对中实现完全合规。这些结果表明，在最具影响力的网站中，色彩对比度问题仍是普遍存在的无障碍访问障碍，且不同领域类别网站间存在显著差异。