Custom Accent Colour
Perhaps a colour picker could be displayed, or three channel sliders made available, or even but a bare hex field.
(it would also be nice having the option not to tint the background with the set accent colour, reserving it exclusively for upfront controls)
Aren't you happy with the current accent color customization?
Implementing the color picker is simple, since it already exists in the application.
However, to do what you're asking, it would require a lot of modifications; what I mean is that you'd have to define the color for each element that uses the "colorAccent" or "colorPrimary" attributes.
But maybe I can do something about the background color. I'll have to test it.
In any case, to be honest, at the moment, I don't want to waste time on this subject. I'll leave it open until I do some tests, but maybe I'll close it.
2 months later I reread this topic and I won't do anything about it.
On the subject of themes, we already have sufficient settings, especially since the night mode colors have been improved with commit 86b6bfb.