.stack-filter-btn { cursor: pointer; background: transparent; color: inherit; }
.stack-filter-btn.active { border-color: currentColor; opacity: 1; }
.stack-filter-btn:not(.active) { opacity: 0.45; }
.stack-filter-btn:hover:not(.active) { opacity: 0.75; }
.stack-cat[hidden] { display: none; }