In macOS's Terminal app, the default theme (Basic) adapts dynamically to system settings, but as soon as I customize the Basic theme from the preferences menu, it stops adapting. Is there a way to manually configure Terminal to look at the system mode and choose a theme appropriately?
macOS's Terminal app doesn't have a setting to dynamically pick a theme. However, when customizing a theme (or creating your own), you can pick colors that dynamically adapt to the OS.
When choosing colors, go to the third tab and, from the drop-down at the top, choose Developer. These colors will adapt automatically to the current system theme.
⚠️ Caveat: If you modify these colors in any way (even only their opacity), they will stop adapting to the system theme.