/**
 * 右下角浮动按钮样式
 * 包括：返回顶部按钮、深色模式切换按钮
 */

.floating-buttons {
  position: fixed;
  right: 20px;
  bottom: 20px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  z-index: 9999;
}

.float-btn {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: none;
  background: #fff;
  color: #333;
  font-size: 18px;
  cursor: pointer;
  box-shadow: 0 2px 10px rgba(0,0,0,.15);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all .2s;
}

.float-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 15px rgba(0,0,0,.2);
}

:root.dark .float-btn {
  background: #2a2e37;
  color: #e5e7eb;
}

.back-to-top-btn {
  background: var(--primary-grad-deep);
  color: #fff;
}

.back-to-top-btn:hover {
  background: var(--primary-deep);
}

/* 响应式：移动端 */
@media(max-width:600px){
  .floating-buttons { right: 12px; bottom: 12px; }
  .float-btn { width: 40px; height: 40px; font-size: 16px; }
}