<style>
/* 设置下拉按钮的样式 */
.dropbtn {
  background-color: #4CAF50;
  color: white;
  padding: 16px;
  font-size: 16px;
  border: none;
  cursor: pointer;
}

/* 容器 <div> - 需要放置下拉内容 */
.dropdown {
  position: relative;
  display: inline-block;
}

/* 下拉内容（默认隐藏） */
.dropdown-content {
  display: none;
  position: absolute;
  background-color: #f9f9f9;
  min-width: 160px;
  box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
  z-index: 1;
}

/* 下拉链接 */
.dropdown-content a {
  color: black;
  padding: 12px 16px;
  text-decoration: none;
  display: block;
}

/* 悬停时更改下拉链接的颜色 */
.dropdown-content a:hover {background-color: #f1f1f1}

/* 悬停时显示下拉菜单 */
.dropdown:hover .dropdown-content {
  display: block;
}

/* 显示下拉内容时，更改下拉按钮的背景颜色 */
.dropdown:hover .dropbtn {
  background-color: #3e8e41;
}
</style>

<div class="dropdown">
  <button class="dropbtn">Dropdown</button>
  <div class="dropdown-content">
    <a href="#">Link 1</a>
    <a href="#">Link 2</a>
    <a href="#">Link 3</a>
  </div>
</div>