@Gargron The visual update looks great!

I noticed two things:
I'm not sure if people who are unfamiliar with Mastodon would understand what the "Low-key public" status visibility means. The short description in the drop-down menu is not very informative.
You could add a "Help" button to each entry, pointing to https://docs.joinmastodon.org/user/posting/#unlisted for the "Low-key public" option.

The "Menu" drop-down icon above the status compose box is a little hard to see, because of the low contrast with the background.