CSS is Cascading Style Sheets, the language used to control the visual presentation of HTML content.
Example of CSS
A card layout displays three columns on a desktop and one on a phone. CSS sets those breakpoints, spacing, colors, and type sizes while the underlying HTML content remains the same.
Why CSS matters
It matters because development decisions affect speed, security, scalability, tracking, SEO, and maintenance. A site that looks good but is fragile or hard to update can quietly hold back every marketing channel.
Related terms
Frequently Asked Question
What does CSS mean?
CSS means Cascading Style Sheets, the language used to control the visual presentation of HTML content.