What is CSS?
Also called: Cascading Style Sheets
The short answer
CSS is the language that controls how a web page looks: colours, fonts, spacing, layout, animation and how the design adapts to each screen.
What people say: “the styling”, “the look”.
CSS, explained
CSS rules select elements and set their properties. The cascade decides which rule wins when several apply, based on origin, layer, specificity and order.
Modern CSS handles work that once needed JavaScript: grid and flexbox layout, container queries, scroll-driven animation and view transitions.
Questions people ask about CSS
What is CSS?
CSS is the language that controls how a web page looks: colours, fonts, spacing, layout, animation and how the design adapts to each screen.
Related terms
HTML is the language that gives a web page its structure: headings, paragraphs, links, images, forms and every other element on the page.
CSS GridCSS Grid is a two-dimensional layout system that places elements into rows and columns at once, making complex page layouts possible with a few lines of CSS.
FlexboxFlexbox is a one-dimensional CSS layout system for arranging items in a row or column, with easy alignment, spacing and wrapping.
Tailwind CSSTailwind CSS is a utility-first CSS framework where small single-purpose classes like p-4 and text-lg are composed directly in HTML to style components.
Scroll-driven animationScroll-driven animation ties an animation's progress to scroll position instead of time, so elements animate exactly as far as the reader has scrolled.
Part of the Web Encyclopedia by Apex Flow Digital. Definitions are general knowledge, kept current, with no invented statistics.