HTML & CSS
The markup and styling languages that define the structure and appearance of every webpage.
HTML and CSS are the foundational building blocks of the web. While frameworks abstract much of the work, deep HTML and CSS knowledge — layout systems, accessibility semantics, responsive design — remains essential for frontend engineers who need to build interfaces that work correctly at every screen size and for every user.
Typical time to job-readiness: ~2 months.
Learning HTML & CSS
Beginner
Learn semantic HTML, the box model, Flexbox, and CSS Grid. Build responsive layouts from scratch — no framework — to develop real intuition for how the browser renders.
Intermediate
Master CSS custom properties, animations and transitions, accessible markup (ARIA roles, focus management), and complex responsive patterns with media queries.
Advanced
CSS architecture at scale (cascade layers, naming systems), critical rendering path optimization, and deep accessibility auditing. Frontend interviews often include a live CSS layout challenge.
Key concepts
- Semantic HTML elements and why they matter for accessibility and SEO
- The CSS box model: content, padding, border, and margin
- Flexbox for one-dimensional layouts and Grid for two-dimensional
- CSS specificity, cascade, and inheritance rules
- Responsive design with media queries and mobile-first approach
- Accessibility: ARIA roles, keyboard navigation, and focus management
Common interview topics
- Explain the CSS box model and how box-sizing: border-box changes it
- When would you use Flexbox vs CSS Grid
- What does 'semantic HTML' mean and why does it matter
- Explain CSS specificity and how conflicts between rules are resolved
- How do you implement a responsive layout without a framework
- What is the purpose of ARIA attributes and when should you use them