# How to Add Dark Mode to Any Website in 5 Minutes (with localStorage)

Dark mode isn't just a trend anymore – it's an expected feature. Users want it for better readability and less eye strain.

The good news? You can add it to any existing website in about 5 minutes with pure CSS and a few lines of JavaScript.

No frameworks. No dependencies. Just copy, paste, and customize.

What You'll Build

A complete dark mode toggle that:

✅ Saves user preference in localStorage (persists across visits)

✅ Detects system theme automatically

✅ Lets users override system preference

✅ Works on any existing website

Step 1: CSS Variables (The Foundation)

CSS variables make theme switching effortless.…