.back-to-top{z-index:var(--z-sticky);border-radius:var(--radius-round);background:var(--back-to-top-bg,var(--primary));color:#fff;width:48px;height:48px;box-shadow:var(--shadow-primary-md);cursor:pointer;opacity:0;pointer-events:none;transition:opacity var(--transition-base), transform var(--transition-base), background var(--transition-fast);border:none;justify-content:center;align-items:center;display:flex;position:fixed;bottom:clamp(16px,3vw,28px);right:clamp(16px,3vw,28px);transform:translateY(12px)}.back-to-top--visible{opacity:1;pointer-events:auto;transform:translateY(0)}.back-to-top:hover{filter:brightness(.9);transform:translateY(-2px)}@media (width<=768px){.back-to-top{width:44px;height:44px}}