# Underline To Background

> A text component that animates a text underline into a text background.  The component creates a separate div element positioned absolutely below the text (instead of the regular underline elements with CSS pseudo-elements). It animates the height from a thin line (controlled by underlineHeightRatio) to cover the full text height, effectively becoming a background. Simultaneously, it transitions the text color to maintain contrast against the expanding background.

- Author: [Daniel Petho](https://21st.dev/@danielpetho)
- Library: [Fancy Components](https://21st.dev/@danielpetho/library/fancy-components)
- License: mit
- Tags: Textarea
- npm dependencies: framer-motion
- Live preview: https://21st.dev/@danielpetho/components/underline-to-background

## Install

```bash
npx shadcn@latest add "https://21st.dev/r/danielpetho/underline-to-background?api_key=$API_KEY_21ST"
```

Requires a 21st API key (generate one at https://21st.dev/mcp) passed as `API_KEY_21ST`. Free accounts get a limited number of installs per day; unlimited on a paid plan — see https://21st.dev/pricing.

Full component directory: https://21st.dev/llms.txt · More like this: https://21st.dev/community/components/s/textarea.md