Reduce Unused CSS Recommendation Is Still Present in PageSpeed Insights

Even if you have enabled the reduce unused CSS setting for your site, the PageSpeed Insights report will still analyze all your website’s stylesheets.

However, in case any CSS file is greater than 2 KB in size and contains unused code, Google PSI will always display the “Reduce Unused CSS” recommendation.

The main cause of unused CSS despite our feature is when classes and styles are added or changed using JavaScript code.

This means, tag ids, classes, or tags, recognized by Website Speedy in the JavaScript code of your website are preserved because the JavaScript code may change the page contents at any given time.

Sometimes, the “Reduce unused CSS” opportunity may not be transferred to the “Passed audits” list. The “Potential Savings” value, however, needs to show a much more noticeable enhancement.

Additionally, CSS code might be applied for future development or for the browsers that do not support the modern CSS technology.

Our “Remove unused CSS” feature may reduce the amount of CSS that is unused, it may not remove all the unused CSS completely. This is because some CSS might be only applied when some conditions are met or in some pages only and such CSS may not be easily identified through automated methods or through browser developer tools.

It can be a time-consuming process to reduce the amount of unused CSS, automated applications or plugins which perform such actions can be potentially problematic and cause visual issues to a site.

However, the most effective and accurate approach for it is to manually evaluate the code and determine which CSS code is essential and which one is unnecessary.