> Lightweight: limit the size to 3KB (gzipped).

  $ curl -H 'accept-encoding: gzip' -I https://alvaromontoro.github.io/almond.css/dist/almond.min.css | grep content-length
  content-length: 4198

Looks like they slipped past their alleged limit and didn’t notice or didn’t update their documented target. My observation with this kind of stylesheet is that they normally do slip like this.

I would also say that 19KB/4KB gzipped is not particularly lightweight for this type of stylesheet, though in its defence it is more thorough in its element coverage than most (… which just means that the significant majority of it will be dead code on most pages).

For the rest, I’m not going to go into it (nothing stands out as particularly good or bad) save this one point that offends me greatly:

  --font-weight-bolder: 700;
  --font-weight-bold: 400;
  --font-weight-normal: 200;
  --font-weight-thin: 100;

These figures are offensive. 700 is bold, 400 is normal, 300 is unpleasantly thin at 16px on most platforms and most fonts (macOS under default configuration being the exception, as they perform glyph dilation that no one else does), 200 is illegibly thin below maybe 30px, and 100 is hairline, not to be used below around 50px. The font stack of `Helvetica, Arial, sans-serif` is the dubious salvation of these weights (a dodgy font stack too, by the way, better simplified to just sans-serif), as I think (but certainly don’t know) that all platforms will by default resolve this to a font that does not possess a lighter weight than 400. But if someone has it resolve to a font that does contain a weight below 400, you’ve just wrecked the page for them.