I use rclone serve http as a convenient way to get files onto very old computers/OSes for retrocomputing fun/experiments/etc. (Examples: Windows XP with IE6, old Macs, etc.) The UI is simple enough that even very old browsers on these systems work fine with it to download files. The problem is that the stylesheet includes background: #ffffff which forces the background to white, even if I set desired colors in the browsers in question.
I've even tried accessibility stylesheet overrides (at least in the case of IE) but it doesn't seem to hold, for whatever reason the stylesheet rclone is offering inline takes precedence even over a user stylesheet.
Feature request is either a way to override the background color directly that's given in the served CSS, or even simply a --dark option or similar that sets the background color to black and the text color to white.