Color mode has invisible tri-state button; use two state or dropdown

[jdittrich]

Current state: The mode toggle changes between dark/light/system by repeatedly clicking the button to cycle through modes. This is non-standard and the three-state-ness is hard to guess

Suggestion: Use a two state switch (reasoning here) or an explicit three-option selector like a (custom-styled) drop-down.

[oswwwaldo]

I'd love to take on this issue! I do agree it makes no sense to have the user go through three clicks to cycle through a binary menu. I made my edits and opened a PR! I thought about the dropdown bit but I wasn't sure since "System", especially to casual audiences, may be confused as to what it's intention is and may cause friction/dead clicks). So I stuck with the two state button (plus simpler for me haha)