PageSpeed: Reduce Unused CSS

Pages with unused CSS that are larger than necessary in bytes and reducing page speed.

How to Analyse in the SEO Spider

To populate this filter the PageSpeed Insights API must be connected via ‘Config > API Access > PSI’.

View URLs with this issue in the ‘PageSpeed’ tab and filter and use the lower ‘PageSpeed Details’ tab to click on the issue on the left-hand side, and see details of the CSS files on the right-hand side.

Bulk export the pages and CSS via ‘Reports > PageSpeed > Reduce Unused CSS’.

What Triggers This Issue

This issue is triggered when pages include unused CSS, leading to file sizes that are larger than necessary and subsequently reducing page speed.

How To Fix

Remove dead rules from stylesheets to reduce unnecessary bytes consumed by network activity. Inline critical CSS and defer the loading of CSS not used for above the fold content to improve page load performance.