CSS

CSS (short for Cascading Style Sheets) is the language that tells websites how to look, like picking the outfit for your HTML.

CSS comes from the early days of the web (mid-1990s), when developers wanted a cleaner way to separate structure (HTML) from style (colors, fonts, layout). Instead of messing with formatting inside the HTML, CSS lets you control the entire vibe of a website from one place — what colors to use, how big the text should be, whether buttons have round corners, and where stuff goes on the page.

Imagine HTML as the skeleton of a site. CSS is the clothes, makeup, lighting, and stage design. You can make the same content look sleek and modern or retro and pixelated — just by changing the CSS. It works by selecting HTML elements and applying rules: “all headers should be blue,” or “this box should be centered with a shadow.”

It’s called cascading because styles can layer — one rule can override another depending on where it appears, which gives you powerful control but also the occasional headache.

Curious? Play around on CSS-Tricks — it’s a classic.