What it is and the problem it solves
CSS is a style sheet language that solves the problem of entangled content and presentation in early web documents. Before CSS, font tags,
How it works
CSS resolves styling conflicts using a predictable cascading priority scheme. It applies rules to markup elements based on selector specificity, source order, and importance flags. It operates independently of content markup, relying on declarative property-value pairs.
What works
Separation of content and presentation works reliably for static documents. The cascading priority scheme resolves conflicts predictably. MIME type registration (text/css) and W3C validation enable interoperability and correctness checking.
What does not
CSS does not control behaviour, interactivity, or content generation. It cannot conditionally render elements, respond to user input without JavaScript, or manage document structure. It has no built-in logic, loops, or variables in the 1996 standard.
What it changes
It changes how web developers think about documents: presentation is no longer embedded in tags or dictated by browser defaults. Layout, colour, and typography become external, composable, and testable layers.
Is it worth your time
Yes—if you write or maintain HTML, XML, or GTK interfaces, and need consistent, reusable presentation logic. It reduces duplication, enables theme switching, and isolates visual changes from structural ones.
