/* 返回顶部按钮和滚动百分比样式 */
.Xc_backtop {
  position: fixed;
  bottom: 20px;
  right: 20px;
  z-index: 999;
  display: flex;
  flex-direction: column-reverse;
  align-items: center;
  gap: 10px;
}

.Xc_backtop_num {
  background: var(--background);
  color: var(--main);
  width: 40px;
  height: 40px;
  border-radius: 50%;
  font-size: 12px;
  opacity: 0;
  transition: opacity 0.3s ease, transform 0.3s ease;
  box-shadow: var(--box-shadow);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-right: 0;
}

.Xc_backtop_btn {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--background);
  color: var(--main);
  border: none;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.3s ease, transform 0.3s ease;
  box-shadow: var(--box-shadow);
  display: flex;
  align-items: center;
  justify-content: center;
}

.Xc_backtop_btn:hover {
  transform: translateY(-3px);
  color: var(--theme);
}

.Xc_backtop_btn .icon {
  width: 20px;
  height: 20px;
}

.Xc_backtop.visible .Xc_backtop_num,
.Xc_backtop.visible .Xc_backtop_btn {
  opacity: 1;
}

/* 响应式设计 */
@media (max-width: 768px) {
  .Xc_backtop {
    bottom: 15px;
    right: 15px;
  }
  
  .Xc_backtop_btn,
  .Xc_backtop_num {
    width: 35px;
    height: 35px;
    font-size: 11px;
  }
  
  .Xc_backtop_btn .icon {
    width: 18px;
    height: 18px;
  }
}