docs main branch SVG warnings

I'm getting these two on Firefox:

10:39:18.653 Unexpected value 2.5rem parsing width attribute. twbs-bootstrap.netlify.app
10:39:18.653 Unexpected value 2rem parsing height attribute. twbs-bootstrap.netlify.app

It seems to come from the navbar logo.

EDIT: it seems this leads to improper display on old FF: