Introduction to HTML and CSS

The two languages every web page is built from.

ConceptualbeginnerBeginner-friendlyFull course available

Overview

HTML describes what's on a page (structure and content); CSS describes how it looks (presentation). This entry is the on-ramp before the dedicated HTML and CSS guides/course -- what the split between the two languages actually means and why it matters.

What it is
A short orientation to the two foundational web languages and how they divide responsibility: structure versus presentation.
Why it's used
Every browser-rendered page, no matter what framework built it, ultimately compiles down to HTML and CSS.
Where it fits
Right after general programming basics, before the full HTML & CSS Fundamentals course.

Core concepts

  • Elements and tags
  • The document tree (parents, children, siblings)
  • Separating structure from presentation
  • The browser as a renderer, not just a viewer

Example

The <h1> and <p> tags describe structure and meaning (this is a heading, this is a paragraph); the style attribute is CSS, describing appearance -- the same paragraph could be restyled without touching its meaning.

<!doctype html>
<html>
  <body>
    <h1>Hello</h1>
    <p style="color: teal;">A paragraph.</p>
  </body>
</html>

Common use cases

  • Building any web page, regardless of framework
  • Reading and modifying an existing site's markup
  • Understanding what a framework like React ultimately renders to

Project ideas

  • Build a single page with a heading, a paragraph, and one styled element, with no CSS framework

Official references