Languages
The language you choose constrains everything else — framework, libraries, hiring, ecosystem.
Advanced TypeScript
The type-level TypeScript that Stage 5 deferred — narrowing, discriminated unions, generics, conditional/mapped/template-literal types, satisfies, branded types, declaration files, and tsconfig strictness. How to make illegal states unrepresentable.
Frontend Frameworks
The component-based UI scaffolding around your app. React, Vue, Svelte, Solid, Astro — and when each is the right pick.
Advanced React
Beyond components — reconciliation, the rules of hooks and why they exist, render performance, Server Components vs client, Suspense and concurrent rendering, and the state-colocation discipline that keeps large apps fast.
Styling
How you write CSS shapes the entire development experience. Tailwind dominates; shadcn/ui is the component layer of choice.
Advanced CSS
Beyond utility classes — the cascade and specificity, stacking contexts, modern layout (fl/grid/container queries), design tokens and theming, and why most "CSS is broken" moments are really a misunderstanding of the cascade.
State Management
Two kinds of state, two kinds of tools. Server state (TanStack Query), client state (Zustand, React built-ins), form state (React Hook Form + Zod), URL state.
Forms & Server Actions
Controlled vs uncontrolled inputs, React Hook Form + Zod, async validation, surfacing server errors, optimistic updates, and React 19 / Next.js 16 Server Actions end-to-end.
Design Systems & Storybook
What a design system is (tokens → primitives → components), building accessible reusable components, Storybook for isolated development and docs, and visual-regression testing.