Resolve theme from mode or custom colors.
'auto' follows the user's prefers-color-scheme media query. This degrades gracefully to 'dark' in environments without window.matchMedia (SSR, tests, non-browser runtimes).
'auto'
prefers-color-scheme
'dark'
window.matchMedia
Resolve theme from mode or custom colors.
'auto'follows the user'sprefers-color-schememedia query. This degrades gracefully to'dark'in environments withoutwindow.matchMedia(SSR, tests, non-browser runtimes).