Just got around to using the new-ish Clean theme.
The theme itself did not appeal, but the style guide was terrific.
The sample code provided allowed me to get the clean design I'd been imaging for a couple of years.
And this is from someone with no CSS experience whatsoever. My previous coding allowed me to try plugging in new values into the provided samples and voila - it worked. Well, worked after lots of trials and previews.
But it made for a great weekend project.