Viewport
The user’s visible area of a web page, typically displayed as a rectangle. It varies with the device, such as mobile, tablet, or desktop.
Media Queries
CSS techniques that allow the web page to adapt its layout based on the device's characteristics, such as screen size and resolution.
Fluid Grid
A responsive layout structure that uses proportional sizing instead of fixed units, allowing content to resize smoothly for different screen sizes.
Responsive Images
Images that scale nicely with the layout, using CSS to adapt or using HTML attributes like 'srcset' for different resolutions.