Use :has() to style parent elements based on their descendants

Before :has(), styling a parent based on its children required JavaScript: detecting state, toggling classes, and keeping DOM and styles in sync. This created coupling between styling logic and application logic. :has() moves that relationship back into CSS where it belongs, reducing JavaScript complexity, eliminating class-toggling boilerplate, and making styling intent readable in the stylesheet itself.

Quick Reference

• :has() selects an element when a matching descendant exists inside it
• It is the parent selector CSS has needed for decades
• Baseline support since late 2023 — all major browsers include it
• Avoid complex :has() selectors in hot reflow paths — they can affect layout performance

Check

Look for patterns in this code where JavaScript toggles a class on a parent element based on the state or content of a child element. These are candidates for replacement with :has().

Fix

Replace the JavaScript class-toggling logic with a CSS :has() selector. Show the selector that targets the parent element when the relevant child condition is met.