HTML/CSS

The foundational languages for structuring web content and applying visual styles across all modern browsers.

HTML5 provides the semantic backbone for web documents using tags like <main> and <article>, while CSS3 handles the presentation layer through Flexbox, Grid, and media queries. These standards, maintained by the W3C and WHATWG, ensure cross-platform compatibility for 5.3 billion global internet users. Mastering this duo allows developers to build responsive, accessible interfaces that load quickly and rank effectively on search engines.

https://developer.mozilla.org/en-US/docs/Learn/Getting_started_with_the_web/HTML_and_CSS_basics