I want to check through my site (7 pages plus 3 CSS files) to eliminate unused CSS styles in the style sheets. Is there a quick way in D8 to find out what is redundant in the CSS? Or maybe there is an add-in for this.

I also want to do a semantic check but I guess this is manual

Thanks

I'm not to sure if this is what you need but this is a Firefox Extension that you can use to debug your code. It also works with IE and Opera. www.getfirebug.com/