CSS Overflow is a feature of Cascading Style Sheets (CSS) that allows web developers to control how content is displayed when it exceeds the boundaries of its containing element. It can be used to create responsive designs that adapt to different screen sizes, and to hide or show content depending
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.