Checks
Legible font sizes
Checks inline CSS for font-size declarations under 12px, text small enough that most visitors on a phone screen would struggle to read it without zooming.
What this check looks for
This check scans <style> blocks and style attributes for font-size declarations, converting points to pixels for comparison, and flags any below 12px. Three or more such tiny-font declarations trigger a warn, listing each one found with its computed pixel value. Fewer than three (or none) passes — a handful of small labels or captions is tolerated, but widespread tiny text is flagged as a pattern.
Why it matters
Text below roughly 12px is difficult to read comfortably on a phone screen without zooming in, and forcing visitors to zoom to read your main content is a strong signal of a poor mobile experience — the kind of friction that drives people to leave before finishing the page. This check specifically scans inline styles, since that's what a static crawl can see; it won't catch issues from external stylesheets, but tiny inline font sizes usually point to a broader styling pattern worth auditing across the whole CSS. Mobile usability isn't a signal AI answer engines evaluate directly, but it is a confirmed part of how search engines assess overall page experience.
How to fix it
Raise body text to at least 16px and reserve anything below 12px for truly minor legal/caption text, if at all:
<!-- Hard to read on a phone -->
<p style="font-size: 10px;">Free shipping on orders over $50.</p>
<!-- Fixed -->
<p style="font-size: 16px;">Free shipping on orders over $50.</p>If small text appears widely across the site, check whether it's coming from a shared component or design-system default rather than fixing instances one by one.
See how your site scores on this check