.back-to-top{position:fixed;bottom:2rem;right:2rem;width:44px;height:44px;border-radius:50%;background:linear-gradient(135deg,#667eea,#764ba2);color:#fff;border:none;font-size:1.25rem;font-weight:700;cursor:pointer;z-index:999;box-shadow:0 4px 16px rgba(102,126,234,.4);transition:all .3s ease;opacity:0;transform:translateY(16px);pointer-events:none}.back-to-top.visible{opacity:1;transform:translateY(0);pointer-events:auto}.back-to-top:hover{transform:translateY(-3px);box-shadow:0 8px 24px rgba(102,126,234,.5)}.back-to-top:active{transform:scale(.95)}