Thimble makes it ridiculously simple to create your own web pages. Write and edit HTML and CSS right in your browser. Instantly preview your work. Then host and share your finished pages with a single click. Easy, huh?
A simple script that, given a CSS stylesheet and either a .txt file listing URLs of HTML files, or a directory of HTML files, will iterate over them all and list the CSS statements in the stylesheet which are never called in the HTML.