CSS Variables Set a css variable <div class="[--var:0]" ></div> Set a css variable and make it !important <div class="[--var:0_!important]" ></div> :not() selectors an element that is not last child <div class="[&:not(:last-child)]:p-2" ></div> an element that doesn't have attribute data-open <div class="TODO" ></div> an element that doesn't have a child with attribute data-orientation = vertical <div class="[&:not(:has(>[data-orientation='vertical']))]:p-2" ></div> :has() selectors an element that has a child with attribute data-orientation = vertical <div class="has-[>[data-orientation='vertical']]:p-2" ></div>