What modern CSS features are showcased on Style Stage?

Updated

Style Stage showcases a deliberately broad set of modern CSS capabilities, from layout systems like Flexbox and Grid to newer functions such as clamp() and :focus-within. The base HTML is written to be semantic, accessible, and free of nearly all other opinions, so contributors can restyle it without fighting pre-existing design decisions. The project is maintained by Stephanie Eckles (@5t3ph) of ModernCSS.dev and is described as a modern CSS showcase styled by community contributions.

The base HTML you're working with

Because contributors cannot alter the base HTML, the markup is built to give you styling hooks without imposing visual choices. According to the site, the HTML was created to be:

  • Semantic and accessible — structure carries meaning, and accessibility is treated as a baseline requirement rather than an add-on.
  • Free of nearly all other opinions — minimal presentational assumptions, so your stylesheet drives the design.
  • Nested sectioning elements with the .container class — these serve as additional style aids.
  • IDs where needed — included for navigation anchors or accessibility purposes.
  • A small number of extra classes — provided for key elements that lack IDs.
  • A .skip-link — the site explicitly reminds contributors not to forget it.

This matters because your stylesheet is the only layer you control. If you want a layout that depends on a wrapper you don't have, you need to work with the existing sectioning and .container structure instead.

Modern CSS features in the spotlight

The site lists the following as examples of modern CSS it highlights. Browser support for most high-touch features is described as nearly in sync.

Category Features
Layout Flexbox, Grid, position: sticky, two-value display
Customization custom variables, variable fonts
Conditional & functional @supports(), calc(), min() / max() / clamp()
Visual effects gradients, animation, 3D transforms, object-fit
Interaction & state :focus-within
Units & scrolling viewport units, scroll-(margin/padding/snap)
Media queries expanded media query values

A few of these are worth calling out for how they change what a stylesheet can do:

  • clamp() and min() / max() let you express fluid sizing in a single declaration instead of stacking media query overrides.
  • :focus-within lets a parent react when a child receives focus, which is useful for accessible interactive components.
  • scroll-(margin/padding/snap) supports scroll-based layouts and snapping behavior without JavaScript.
  • Two-value display and expanded media query values reflect newer syntax that reduces workarounds.
  • Variable fonts and custom variables make typography and theming more flexible within a single stylesheet.

Accessibility is part of the showcase

Style Stage pairs its CSS focus with an explicit accessibility expectation. The site states that the community has "an improved understanding of what it takes to make accessible experiences," and the guidelines require that your design passes accessible contrast, verified using aXe. Responsive design is also required.

So the features above aren't just a list to demonstrate — they're tools you're expected to apply in a design that remains usable and readable. For example, using :focus-within or position: sticky is fine, but the result still has to meet contrast and responsiveness checks.

Why this matters if you're contributing

If you plan to submit a stylesheet, the practical takeaways are:

  1. You can't change the HTML, so design around the existing semantic structure, .container nesting, IDs, and .skip-link.
  2. You have a wide feature set available, but the final submission must be compiled, unminified CSS, and it will be autoprefixed and prepended with the CC BY-NC-SA license plus attribution from your metadata.
  3. Your design must be responsive and pass accessible contrast — aXe is used for verification.
  4. Asset links, including fonts, must be absolute to external resources, and you retain copyright to original graphics while ensuring all graphics are appropriately licensed.

In short, Style Stage is both a gallery and a constraint exercise: the base HTML stays fixed and accessible, and the modern CSS feature list is the palette you use to restyle it.