Cascading Style Sheets (CSS) is a stylesheet language used to describe the presentation of a document written in HTML. CSS controls the layout of multiple web pages all at once. It allows you to apply styles to web pages, including colors, fonts, and spacing.
Using CSS improves the look and feel of your website. It separates content from design, making it easier to maintain and update. With CSS, you can create visually appealing websites that enhance user experience.