Try It

See how Nightfall transforms real websites. Enter a URL or explore the pre-computed examples below.

Live URL analysis requires the Nightfall CLI running locally. Install it and run the command shown below instead. Explore the pre-computed examples to see the output.

Pre-computed Examples

github.comLight to Dark

GitHub's light theme transformed into a dark variant. Note how the blue link color brightens slightly while the green success color becomes more vivid.

Original

#ffffff

#f6f8fa

#24292f

#0969da

#1f883d

Generated

#0d1117

#161b22

#e6edf3

#2f81f7

#3fb950

npx nightfall-css scan --url https://github.com
npx nightfall-css generate --format css-variables

Run It Locally

To analyze any site, run Nightfall locally. It launches a headless browser, visits your pages, and extracts every color:

# Install
npm install -g nightfall-css

# Scan your running dev server
npx nightfall-css scan --url http://localhost:3000

# Generate the opposite theme
npx nightfall-css generate --format css-variables

# Open the interactive preview
npx nightfall-css preview