Definition:
When you create a website or web page, each section—like header, footer, layout, and buttons—has a lot of CSS code.
You cannot keep all this code in a single file, so developers use Modular CSS, keeping separate files for each section—for example, header.css for the header section, containing only CSS for that part, and similarly for other sections.
Using Modular CSS makes managing large CSS code simple. If you make a change in one section, it updates that section on all pages of your website.
When you create a website with many pages, each page contains multiple sections, such as the header, footer, etc. Each section has a lot of code, like CSS and HTML, for formatting the page. If you want changes to reflect automatically across all pages, organizing code this way helps.
Instead of keeping all CSS in one large file, you create separate files—for example, footer.css, which contains only the CSS for the footer section.
This diagram represents how modular CSS files are organized for a webpage:
header.css)
layout.css)
Each colored box represents a separate CSS file applied to that section of the webpage.