@gbrnt maybe - i checked on ff/android, and you're right, it doesn't show it properly there.
maybe it is fonts? on the original page, the specified font-family is < "mastodon-server-sans-serif", sans-serif >, whereas i have my fonts nailed down to Atkinson Hyperlegible... but if i switch to Roboto in the Inpsector, suddenly it gets rendered! so yes, it does appear to be a font thing!