Customization

Custom CSS

To customize the styles applied to your Starlight site when using the Starlight Next.js theme, you can provide additional CSS files to modify or extend the Starlight and Starlight Next.js theme default styles.

Learn more about custom CSS in the Starlight documentation.

Cascade layers

Like Starlight, the Starlight Next.js theme uses cascade layers internally to manage the order of its styles. This ensures a predictable CSS order and allows for simpler overrides. Any custom unlayered CSS will override the default styles from Starlight and the Starlight Next.js theme.

If you are using cascade layers, you can use @layer in your custom CSS to define the order of precedence for different layers relative to styles from the starlight and nextjs layers:

src/styles/custom.css

@layer my-reset, starlight, nextjs, my-overrides;

The example above defines a custom layer named my-reset, applied before all the Starlight and Starlight Next.js theme layers, and another named my-overrides, applied after all Starlight and Starlight Next.js theme layers. Any styles in the my-overrides layer would take precedence over the Starlight and Starlight Next.js theme styles, but Starlight or the Starlight Next.js theme could still change styles set in the my-reset layer.