Dark mode chosen by 70%+ users. But doing it right means more than inverting.
Base colors
Not pure black (#000) — soft (#0f172a). Not pure white — muted.
WCAG contrast
4.5:1 minimum. Verify with WebAIM.
Buttons
Light mode color may be too bright in dark.
Images
brightness:0.8 filter.
Implementation
prefers-color-scheme + JS toggle. localStorage.