HTML stands for HyperText Markup Language. It is the standard markup language used to create and structure content on the web. HTML elements are the building blocks of web pages, defining headings, paragraphs, links, images, and more.
CSS stands for Cascading Style Sheets. It is a stylesheet language used to describe the presentation of a document written in HTML. CSS controls layout, colors, fonts, spacing, and the overall visual appearance of web pages.
JavaScript is a versatile, high-level programming language primarily used for adding interactivity and dynamic behavior to web pages. It can manipulate the DOM, handle events, communicate with servers, and much more. It is an essential part of modern web development alongside HTML and CSS.
Responsive design is an approach to web design that ensures web pages render well on a variety of devices and screen sizes. It uses flexible grids, flexible images, and CSS media queries to adapt the layout to the viewing environment, providing an optimal user experience on desktops, tablets, and smartphones.