Low impact · weight 2 · worth up to 0.9 points of the total score
Inline style attributes cannot be cached, overridden by a stylesheet, or covered by a Content Security Policy that forbids inline styles. In quantity they also bloat every HTML response.
Move repeated inline styles into CSS classes and keep style attributes for values genuinely computed at runtime.
Check a page for this, and the other 41 checks at once
Viewport meta tag is present
Without it mobile browsers render the page at desktop width and shrink it to fit, which fails Google's mobile usability bar and leaves text unreadable on a phone.
HTML parses without errors
Browsers repair broken markup silently, and each one repairs it slightly differently. Unclosed and misnested tags are where a layout that works in one browser collapses in another.
Element ids are unique
An id must appear once per document. Duplicates break label-to-input pairing, in-page anchors, and any script that looks an element up by id, and every one of those failures is silent.
Buttons have accessible names
A button whose only content is an icon announces itself to a screen reader as just "button", which tells the user nothing about what pressing it will do.
