Responsive design is a method to ensure that a website looks and functions well on a variety of devices and screen sizes. It's not tied to specific technologies but rather involves a set of design principles and practices that make web content adapt to different environments.

Key Principles of Responsive Design

Responsive design is centered around the idea that web content should be accessible and legible across all devices, from desktop monitors to mobile phones. This approach uses HTML and CSS to resize, hide, shrink, enlarge, or move the content to make it look good on any screen¹.

One of the core aspects of responsive design is the use of the viewport meta tag. This tag instructs the browser on how to handle the page's dimensions and scaling. For example, setting the viewport width to the device's width ensures that the layout is optimized for mobile screens².

Implementing Responsive Design with CSS

Responsive design can be achieved through various CSS techniques: