Understanding :is() vs :where() in CSS
The :is() and :where() pseudo-classes allow you to group multiple selectors and apply styles efficiently, but they differ in how they contribute to specificity.
:is(selector-list)– The specificity of:is()is equal to the most specific selector inside the list. This means it can override less specific rules.:where(selector-list)– The specificity of:where()is always zero, regardless of the selectors inside it. This makes it ideal for utility or default styles that should not override other rules.Both simplify writing complex selectors, but
:where()avoids specificity conflicts while:is()preserves them.
In this example, the headings get dark blue because :is() preserves specificity. The regular paragraph gets gray from :where(), but the .special paragraph overrides it with black because :where() has zero specificity.
Use
:is()when you want grouped selectors to maintain specificity and possibly override other rules.Use
:where()for default or fallback styles that should not interfere with more specific rules.Combine them with other pseudo-classes for precise and readable CSS.
Test across browsers, as support for
:is()and:where()is broad in modern browsers but may require fallback for older ones.