CSS Positioning is a powerful tool for controlling the layout of webpages. It allows developers to precisely control the position of elements on a page, giving them the ability to create complex layouts with relative ease. CSS Positioning can be used to create responsive designs that adjust to different screen sizes
From Wikipedia
Cascading Style Sheets (CSS) is a style sheet language used for specifying the presentation and styling of a document written in a markup language, such as HTML or XML. CSS is a cornerstone technology of the World Wide Web, alongside HTML and JavaScript.