.back-to-top{right:var(--space-4);bottom:var(--space-4);z-index:40;background:var(--color-primary);color:#fff;cursor:pointer;width:44px;height:44px;box-shadow:0 4px 16px var(--color-shadow);opacity:0;pointer-events:none;transition:opacity var(--transition-fast), transform var(--transition-fast), background var(--transition-fast);border:none;border-radius:50%;justify-content:center;align-items:center;display:inline-flex;position:fixed;transform:translateY(8px)}.back-to-top--sichtbar{opacity:1;pointer-events:auto;transform:translateY(0)}.back-to-top:hover{background:var(--color-accent)}@media (min-width:768px){.back-to-top{width:48px;height:48px;right:var(--space-6);bottom:var(--space-6)}}