More themes, and following your system

The theme picker has grown up.

• Light and Dark — the obvious two.
• High Contrast — for when the default borders and text are not doing enough.
• Gruvbox and Dracula — two palettes that people already have opinions about, done properly rather than approximated.
• System — follow whatever your operating system is doing, and change when it changes.

System is the default, and it is the one most people should leave alone: a laptop that goes dark at sunset should take GitGumbo with it without anyone opening a settings page.

The picker shows each theme as a small board rather than a colour swatch, since what you actually want to know is what a card looks like in it, not what the accent colour is in isolation.

We built more palettes than shipped. Several were cut for the ordinary reason — they looked good in a screenshot and were tiring to work in — and one was cut because its contrast could not be made to hold up. A theme that fails on contrast is not a style choice, so it did not ship.