# Responsive Design and the Viewport

A responsive page fits whatever screen it's on, and it starts with one line in the head, the viewport line, plus knowing what breaks on a phone and how to see it with device mode.

![Cheat sheet: Responsive Design and the Viewport](https://fsdtrainingmedia.blob.core.windows.net/public/images/2026/10/dfd6687c2fd1419394a16571755abdca.webp)

- Category: CSS
- Level: Apprentice
- Tags: CSS, Responsive design, Viewport, Viewport metadata, web-development
- Updated: November 1, 2026

Source: https://www.ask-codey.com/cheat-sheets/css-responsive-design-and-viewport-cheat-sheet