/* 全站通用：回到顶部 / 去到底部 快捷滚动箭头 */
.sn-scrollnav {
  position: fixed;
  right: 28px;
  bottom: 48px;
  z-index: 9999;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.sn-btn {
  width: 46px;
  height: 46px;
  border-radius: 50%;
  background: #fff;
  color: #6366f1;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 16px rgba(15, 23, 42, 0.16);
  border: 1px solid #e8edf5;
  transition: all 0.3s ease;
  animation: snPop 0.4s ease both;
  text-decoration: none;
  cursor: pointer;
}
.sn-btn:hover {
  background: linear-gradient(135deg, #6366f1, #8b5cf6);
  color: #fff;
  transform: translateY(-3px);
  box-shadow: 0 8px 22px rgba(99, 102, 241, 0.4);
  border-color: transparent;
}
.sn-btn.sn-hidden {
  opacity: 0;
  transform: scale(0.6);
  pointer-events: none;
}
@keyframes snPop {
  from { opacity: 0; transform: scale(0.6); }
  to   { opacity: 1; transform: scale(1); }
}
@media (max-width: 768px) {
  .sn-scrollnav { right: 14px; bottom: 24px; gap: 8px; }
  .sn-btn       { width: 40px; height: 40px; }
}