How much CSS do I need to learn to build page layouts?

Start with how CSS selects elements, the box model, spacing, sizing, and how elements behave in normal document flow. Then learn Flexbox and Grid for arranging things, plus media queries for adapting layouts to different screen sizes.

MDN has a CSS learning section you can work through in roughly that order. You don't need to memorize every property. Get comfortable reading an example, changing it, and checking what happens in the browser.

Pick a simple landing page and try to recreate its structure. Start with the header, main content, and footer, then add smaller details. Look things up as you need them rather than waiting until you feel ready.

There's no fixed amount of study time that means you're done. Once you can make a basic page and understand most of the rules you wrote, building is a good way to keep learning.

You probably need fewer rules than you think, but understanding them matters. If a layout is fighting you, check the parent container and the sizing or spacing already in place before piling on more overrides. A simpler layout that's easy to adjust is worth more than a pile of CSS that only works by accident.

Grid is a useful place to focus if your goal is getting an application laid out sensibly rather than doing detailed visual design. For landing pages, you'll still want some basics around spacing, text, colors, and responsive sizing. How much polish you want changes how much there is to learn.

Bootstrap or Tailwind can speed up common styling, but neither makes CSS knowledge irrelevant. You'll have an easier time choosing and customizing their styles if you understand the basic layout and sizing concepts underneath.