Dark mode implementation starts with CSS custom properties. Define color tokens on :root for light theme, override in .dark or [data-theme="dark"] for dark theme.
Prefer system preference: @media (prefers-color-scheme: dark) { :root { --bg: #1a1a2e; } }. This respects user OS settings automatically.
Smooth transitions between themes: * { transition: background-color 0.3s, color 0.3s; }. Apply theme class to element.
Storage: persist user choice in localStorage. Toggle with JavaScript: document.documentElement.classList.toggle('dark').
Avoid pure black (#000) for backgrounds — use dark grays (#1a1a2e, #121212) to reduce eye strain. Maintain sufficient color contrast ratios (WCAG 4.5:1 minimum).
Tailwind CSS has built-in dark mode support with the dark: prefix. next-themes library simplifies dark mode in Next.js projects.
Prefer system preference: @media (prefers-color-scheme: dark) { :root { --bg: #1a1a2e; } }. This respects user OS settings automatically.
Smooth transitions between themes: * { transition: background-color 0.3s, color 0.3s; }. Apply theme class to element.
Storage: persist user choice in localStorage. Toggle with JavaScript: document.documentElement.classList.toggle('dark').
Avoid pure black (#000) for backgrounds — use dark grays (#1a1a2e, #121212) to reduce eye strain. Maintain sufficient color contrast ratios (WCAG 4.5:1 minimum).
Tailwind CSS has built-in dark mode support with the dark: prefix. next-themes library simplifies dark mode in Next.js projects.