Css is used to describes how HTML elements are to be displayed on a web page or layout of HTML documents like fonts, color, margin, padding, Height, Width, Background images, etc. CSS stands for Cascading Style Sheet, here Cascading refers to Section in which we apply Style procedure, and Style refers to color, Margin, font for table paragraphs, and Heading, etc. Sheet refers to how web pages look.

Responsive web design makes your web page look good on all devices.