/* 下拉菜单容器样式 */
.dropdown {
    position: relative;
}

/* 下拉按钮样式 */
.dropbtn {
    display: inline-block;
    cursor: pointer;
}

/* 下拉菜单内容区域默认隐藏 */
.dropdown-content {
    display: none;
    position: absolute;
    background-color: #f9f9f9;
    min-width: 100px;
    box-shadow: 0px 8px 16px 0px rgba(0, 0, 0, 0.2);
    z-index: 1;
    top: 60px;
    left: 20px;
}
.dropdown-content::before {
    content: "";
    position: absolute;
    top: -6px;
    left: 30px;
    border-width: 0 6px 6px;
    border-style: solid;
    border-color: transparent transparent #f9f9f9;
}

/* 下拉菜单内容区域内链接样式 */
.dropdown-content a {
    color: black;
    padding: 6px 10px;
    text-decoration: none;
    display: block;
    text-align: left;
}

/* 鼠标悬停在下拉菜单内容区域内链接上的样式 */
.dropdown-content a:hover {
    background-color: #f1f1f1;
}