1. Parent Form Validation via :has()
:has(:valid)
Watch the parent card turn green when valid without 1 line of JS!
/* Zero-JS Parent Card Validation */
.form-group:has(.form-input:valid:not(:placeholder-shown)) {
border-color: #10b981;
background: rgba(16, 185, 129, 0.08);
}
.form-group:has(.form-input:invalid:not(:placeholder-shown)) {
border-color: #ef4444;
}
2. Sibling Hover Dimming (Focus Effect)
:has(:hover) :not(:hover)
CSS Grid
Flexbox
Subgrid
Animations
OKLCH
Hover over any tag to focus it and dim all other sibling tags.
/* Dim all sibling pills when any pill is hovered */
.tag-cloud:has(.cloud-pill:hover) .cloud-pill:not(:hover) {
opacity: 0.35;
transform: scale(0.95);
}
3. Native CSS Nesting (No SASS/SCSS Required)
& nesting
Native CSS Nesting Demo
Direct hierarchy nesting supported natively in all modern evergreen browsers.
.nested-card {
background: #131f38;
border: 1px solid var(--border);
& h4 { color: #38bdf8; }
& p { font-size: 0.85rem; }
&:hover { border-color: #38bdf8; }
}