[KevinH]

Sigil only searches the stylesheets for selectors that are actually linked to an xhtml file.

None of your stylesheets are linked to anything and therefore none of the selectors are tested (they can only be tested to be present in an xhtml file that links to them).

If you want to see which stylesheets are used or not, simply use the Reports CSS files, which will tell you none of your css files are actually used (linked into any xhtml file).

If I link them all in, running Remove Unused Selectors would remove all of the selectors inside each stylesheets leaving them all completely empty (except for your first one as @page is not a selector). This is exactly the bug I just explained that was already found and fixed in master.

So link all your stylesheets into the one xhtml file. Edit each stylesheet and add
/*css*/
to the top of each css file so that they are not left blank (to workaround the bug that has already been fixed in master) and give it a try. You will see all true selectors are now removed (leaving just the comment) and the first one still has @page since it is not a selector.

Hope this helps,

Kevin