# fonts.customFonts.cssFallback

Part of [Fonts](https://kernstra.com/docs/web-sdk/config/fonts) in the Kernstra Web SDK 1.0.0 configuration reference.

- Type: `string`
- Default: `the display name, then sans-serif`
- Page: https://kernstra.com/docs/web-sdk/config/fonts/customfonts-cssfallback

CSS `font-family` stack for previews.

Web page: https://kernstra.com/docs/web-sdk/config/fonts/customfonts-cssfallback