The Evolution of CSS: What to Expect in 2025

Cascading Style Sheets (CSS) have come a long way from the days of simple floats and clears. The language is evolving faster than ever, adopting features that previously required external tools like Sass or Less.

1. Native CSS Nesting

For over a decade, developers relied on preprocessors to write nested CSS, which mirrored the HTML structure and saved keystrokes. Today, all modern browsers support native nesting.

  /* Before (Sass) */
  .card {
    & .title { color: blue; }
  }
  
  /* Now (Native CSS) */
  .card {
    .title { color: blue; }
  }
        

This reduces our build complexity and brings a beloved feature directly into the browser engine.

2. Container Queries: The Holy Grail of RWD

Responsive Web Design (RWD) has always relied on @media queries, which look at the viewport size. But components often live in different contexts—a sidebar, a main grid, or a modal. If a component is in a narrow sidebar, it should look "mobile", even if the viewport is 1920px wide.

Container Queries (@container) allow elements to adapt based on the size of their parent container, not the window. This enables true component modularity.

3. The :has() Pseudo-class

Often called "the parent selector", :has() allows us to style an element based on its descendants. For example, styling a card differently if it contains an image:

  .card:has(img) {
    grid-template-columns: 1fr 1fr;
  }
        

4. CSS Layers (@layer)

Specificity wars are over. CSS Layers allow you to define explicit priority layers for your styles. You can say that your "theme" styles should always override your "base" styles, regardless of selector specificity.

5. Tailwind CSS v4 and the "Oxide" Engine

Tailwind has completely changed how many of us write CSS. Version 4 introduces "Oxide," a new engine built in Rust. It promises:

• Instant builds: No satisfying dependency graph to traverse.
• Dynamic value support: Use any pixel value arbitrarily without configuration.
• Zero configuration: It infers your config from your CSS usage.

As we move into 2025, the gap between "CSS frameworks" and "Native CSS" is blurring, giving us immense power with less tooling overhead.