@Mastodon I like the overall design. But I don't like the use of color. Mastodon only has versions of violet in its' color scheme. To me it's lacking secondary colors for accents and to really show a hierarchy of elements. Although I don't realy like the violet as it makes everything look sad, I accept that it is the established color for mastodon. But there should be complementary secondary colors that are not just a variation of the primary color. And making the base-color freely definable doesn't make it better.
I am not a designer, but it could look far more friendly and happy with a touch more color.