# Custom CSS has no effect once a visitor toggles dark mode

**What you are seeing**

My custom CSS has no effect once a visitor toggles dark mode.

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## Why it happens

The built-in palette is defined at a higher specificity than a plain :root rule, so a bare :root override loses.

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## What to do

Target :root.light and :root.dark in your custom CSS. (Custom CSS is API-only, there is no UI field.)

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## Related

[Theme's custom CSS or design tokens disappeared after saving AppearanceThe theme is replaced wholesale on save; any client that sends a partial theme wipes the f](https://help.gocapable.com/sites/theme-s-custom-css-or-design-tokens-disappeared-after-saving-appearance.html)

[Password-protected site's sign-in button does nothingPassword sign-in needs JavaScript and modern browser crypto. With JavaScript off, the form](https://help.gocapable.com/sites/password-protected-site-s-sign-in-button-does-nothing.html)

[Other problemsThe rest of this family.](https://help.gocapable.com/sites/other-problems.html)

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_Found it? Good._