I have added a link to repo to my original comment, you can get icons there and look at the style hacks I did. But I am not sure how easy it will be to integrate. I am more of a front-end guy, that's why I went with a browser extension (setting up local instance of saidit seemed daunting and I was unsure if saidit devs would welcome my changes, so going the extension path was a safer option). If you have any front-end related questions, feel free to ask :).

PS: If you think older version were better, they should be in a git history in the repo.

Edit: Forgot to write: styles generation is in src/content.ts.