Responsive Web Design Viewport
https://www.w3schools.com/css/css_rwd_viewport.asp
The viewport is the user's visible area of a web page. The viewport varies with the device, and will be smaller on a mobile phone than on a computer screen. Before tablets and mobile phones, web pages...
Viewport - Wikipedia
https://en.wikipedia.org/wiki/Viewport
A viewport is a polygon viewing region in computer graphics. In computer graphics theory, there are two region-like notions of relevance when rendering some objects to an image. In textbook terminology, the world coordinate window is the area of interest (meaning what the user wants to visualize)...
javascript - What is viewport in HTML. - Stack Overflow
https://stackoverflow.com/questions/2939693/what-is-viewport-in-html
The viewport is the part of the webpage that the user can currently see. The scrollbars move the The viewport is a virtual area used by the browser rendering engine to determine how content is scaled...
Responsive web design basics
https://developers.google.com/speed/docs/insights/ConfigureViewport?hl=ru
Responsive web design basics Set the viewport Ensure an accessible viewport