Customization

Custom CSS

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

Learn more about custom CSS in the Starlight documentation.

Cascade layers

Like Starlight, the Starlight NextJS 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 NextJS 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 NextJS theme layers, and another named my-overrides, applied after all Starlight and Starlight NextJS theme layers. Any styles in the my-overrides layer would take precedence over the Starlight and Starlight NextJS theme styles, but Starlight or the Starlight NextJS theme could still change styles set in the my-reset layer.