HTML and CSS to a working level

What "able to build pages" means

Taking a design and producing a page that looks the same, works on a phone, and doesn't fall apart when the text is long.

It's a distinct skill. Plenty of people who write JavaScript confidently are lost when asked to build a two-column layout by hand.

Mandatory topics

Semantics. Which tags are for what: headings, lists, articles, sections, buttons versus links. This isn't fussiness: markup determines accessibility for screen readers and how search engines understand the page.

A common beginner's mistake is a page built entirely from anonymous blocks. It marks out someone who only studied styling.

The box model. What makes up an element's size: content, padding, border, margin. And how the sizing setting changes that.

Flow and positioning. How elements are laid out by default, how inline differs from block, how the positioning modes work.

Layout. The two modern mechanisms for arranging elements — they get an article of their own. Older float-based techniques needn't be learned, but recognising them in existing code helps.

Selectors and specificity. Why a rule didn't apply — half the time it's specificity.

Working with text. Sizes, line height, wrapping, behaviour with long words.

What matters in practice

Units. When pixels, when relative units, when fractions of the viewport. Getting this wrong is the most common reason layouts break when someone changes their system font size.

Custom properties. They stop you scattering the same value throughout a file.

File organisation. Naming conventions, so that in a month you can still find your way around your own styles.

What interviews check

• Build a layout from a design — the most frequent task.
• Explain the box model. A simple question that surprisingly many flounder on.
• The difference between positioning modes.
• How to centre an element. A classic with several valid answers.
• Why a style isn't applying. Testing your grasp of specificity.

How to practise

Rebuild existing pages. Take a site you like and reproduce its main screen. Then compare against the original with browser tools.

Start with markup, not styling. First a correct structure of appropriate tags, then appearance. The reverse order produces mush.

Check on a real phone. A narrowed browser window lies: no touch, no real fonts, none of the mobile browser quirks.

Break things deliberately. Insert a very long word, replace an image with a missing one, stretch the window. A layout that survives that is a working one.

How long it takes

Reaching "give me a design and I'll build it" takes about two months of regular practice. Faster than learning a programming language, but it demands practice specifically: theory barely helps here.