:optional
Targets form elements (like <input> or <select>) that do NOT have the 'required' attribute.
Quick example
input:optional {
/* Adds a subtle indicator for optional fields */
border-left: 3px solid #cbd5e1;
}:optional Browser Support
Widely available Since 2015 96% global usage
This feature is well established and works across many devices and browser versions. It has been available across browsers since 2015.
Safe to use without fallbacks.
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