.back-to-top{background:var(--accent-color);color:#fff;cursor:pointer;opacity:0;visibility:hidden;width:56px;height:56px;box-shadow:0 4px 14px var(--accent-glow);z-index:999;border:none;border-radius:50%;justify-content:center;align-items:center;transition:all .3s cubic-bezier(.16,1,.3,1);display:flex;position:fixed;bottom:32px;right:32px;transform:translateY(20px)}.back-to-top.visible{opacity:1;visibility:visible;transform:translateY(0)}.back-to-top:hover{background:#333;transform:translateY(-4px);box-shadow:0 6px 20px #00000026}[data-theme=dark] .back-to-top{color:#0a0a0a;background:#fff}[data-theme=dark] .back-to-top:hover{background:#e0e0e0}.back-to-top:active{transform:translateY(-2px)}@media (width<=768px){.back-to-top{width:48px;height:48px;bottom:24px;right:24px}}