01 · Core Languages

The daily authoring surface: the four languages a frontend engineer writes every day.

Priority: Critical

← Knowledge Map

Domains

• HTML & Document Semantics — Meaning and structure of documents — the layer accessibility and SEO build on.
• CSS & Visual Systems — Layout, style, and the architecture of maintainable visual systems.
• JavaScript — The language itself: its object model, execution semantics, and idioms.
• TypeScript — Designing with types: safety and expressiveness at scale.

This is an index. Each domain expands into topics, and each topic into standalone articles following the article template.