Responsive design

Responsive design is an approach to building web pages so their layout adapts to the size of the screen, from wide desktop monitors to narrow phones. A responsive page rearranges and resizes its content with flexible layouts and CSS rules instead of serving a separate mobile website.

It depends on the page correctly declaring its viewport: without that declaration, mobile browsers render the page at a fixed desktop-like width and then shrink it to fit, which defeats the responsive layout entirely and forces visitors to pinch and zoom.

Learn more

• Responsive web design - MDN's guide to responsive design techniques
• Viewport
• CSS