This might solve a few of the edge cases, but making the sizes of everything depend on your screen is a dumb idea. If I move my browser from my small laptop screen to my big external display, I expect to see more content, not larger fonts. My displays are set to scaling factors that are comfortable for me with most things I work with (HN’s tiny fonts being a notable exception). Just set a reasonable size for things (a base font size of 1rem should be fine) and let me use my displays to the fullest.