Structure, style, behavior — the three layers.
The useful version is simpler than the jargon makes it sound. Here are the decisions, checks, and vocabulary that matter most.
01HTML gives meaning and structure
HTML identifies headings, paragraphs, links, forms, navigation, and other content. Semantic structure helps browsers, search engines, assistive technology, and future editors understand the page.
02CSS controls presentation
CSS defines type, color, spacing, layout, and responsive changes. A small design system keeps those choices consistent instead of solving every section from scratch.
03JavaScript adds behavior
JavaScript powers menus, dialogs, validation, and richer interactions. Use it where behavior adds value, and keep core content and links useful when scripts load slowly or fail.