# CSS

Concept · [Technical basics](https://ecosystem.samcarlton.com/technical)

Also called: Cascading Style Sheets, vanilla CSS, stylesheet, stylesheets

Cascading Style Sheets. The language that controls how a web page looks: colors, fonts, spacing and layout. [HTML](https://ecosystem.samcarlton.com/html) says what is on the page and CSS says how it appears.

**For example:** A designer changes one line of CSS and every button on the site [turns](https://ecosystem.samcarlton.com/turn) from blue to green.

## Connects to (8)

- [HTML](https://ecosystem.samcarlton.com/html): HyperText Markup Language.
- [Front end](https://ecosystem.samcarlton.com/front-end): The part of an app or website that people see and tap, running in their browser or on their phone.
- [Design system](https://ecosystem.samcarlton.com/design-system): A shared set of design rules and ready-made interface pieces, such as buttons, colors and type, so every screen looks and works…
- [UX / UI](https://ecosystem.samcarlton.com/ux-ui): UI, the user interface, is what people see and tap on the screen.
- [HTML5](https://ecosystem.samcarlton.com/html5): The current version of HTML.
- [DOM](https://ecosystem.samcarlton.com/dom): Document Object Model.
- [Mobile-first design](https://ecosystem.samcarlton.com/mobile-first-design): Designing for small phone screens first, then expanding the design for larger screens.
- [Tailwind CSS](https://ecosystem.samcarlton.com/tailwind-css): A styling framework for websites.

Map view: https://ecosystem.samcarlton.com/css