What is cssess?

CSSess is a browser tool that finds CSS code you're not actually using on your website. When you install it as a bookmarklet (a saved bookmark that runs JavaScript), you click it while browsing your site, and it scans all the pages to identify CSS rules that aren't doing anything. This helps you clean up bloated stylesheets and reduce the amount of code your site downloads. The tool works by quietly loading each page from your site into a hidden background frame, then comparing all the CSS rules you've written against what's actually being displayed on the page. If a CSS selector isn't matched to any element on the site, it gets flagged as unused. Unlike some older tools, CSSess automatically crawls all the linked pages on your domain instead of making you manually list each URL you want to check. A web developer or site owner would use this to audit their codebase before launching a site or after inheriting a legacy project. For example, if you're redesigning a site and cleaned up the HTML but forgot to remove the old CSS, CSSess would quickly show you all the orphaned rules you can delete. Reducing unused CSS means faster page loads for visitors and less maintenance burden. One thing to keep in mind: the tool only works within a single website domain due to browser security rules, so you can't use it to scan a competitors' sites. Also, the README doesn't detail how it handles dynamic styles added by JavaScript after the page loads, so very dynamic sites might show false positives for styles that only appear under certain conditions.