<!-- 引入font-awesome字体图标库 -->
    <link rel="stylesheet" href="https://cdn.staticfile.org/font-awesome/4.7.0/css/font-awesome.css">

<div class="menu-box">
        <!-- 图标按钮 -->
        <div class="menu-button">
            <div class="line-box">
                <div class="line"></div>
                <div class="line"></div>
                <div class="line"></div>
            </div>
        </div>
        <!-- 菜单列表 -->
        <ul class="menu-list">
            <li><i class="fa fa-sliders"></i><span>设置</span></li>
            <li><i class="fa fa-clone"></i><span>复制</span></li>
            <li><i class="fa fa-share-square-o"></i><span>分享</span></li>
            <li><i class="fa fa-trash-o"></i><span>删除</span></li>
        </ul>
    </div>

// 要操作的元素
const menu_box=document.querySelector('.menu-box');
const menu_button=document.querySelector('.menu-button');

// 为菜单按钮绑定点击事件
menu_button.addEventListener('click',function(){
    menu_box.classList.toggle('active');
})

*{
    /* 初始化 */
    margin: 0;
    padding: 0;
}
body{
    height: 100vh;
    /* 弹性布局 水平+垂直居中 */
    display: flex;
    justify-content: center;
    align-items: center;
    /* 渐变背景 */
    background: linear-gradient(to top left,#84a0f4,#c2e9fb);
}
body::before{
    content: "点击右下角";
    color: #fff;
    font-size: 32px;
    text-shadow: 0 3px 3px #4c6ed3;
}
.menu-box{
    /* 固定定位 右下角 */
    position: fixed;
    bottom: 40px;
    right: 40px;
}
/* 菜单按钮 */
.menu-button{
    width: 50px;
    height: 50px;
    background-color: #5c67ff;
    border-radius: 50%;
    /* 投影 */
    box-shadow: 0 0 0 4px rgba(92,103,255,0.3);
    color: #fff;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    z-index: 1;
    cursor: pointer;
    /* 过渡 */
    transition: 0.2s ease-in;
}
.menu-button:hover{
    background-color: #4854ff;
    box-shadow: 0 0 0 8px rgba(92,103,255,0.3);
}
.menu-button .line-box{
    width: 20px;
    height: 20px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    cursor: pointer;
    transition: transform 0.3s ease-out;
}
/* 菜单按钮图标（三条杠） */
.menu-button .line{
    background-color: #fff;
    width: 100%;
    height: 2px;
    border-radius: 2px;
}
/* 前后两条短，中间的长 */
.menu-button .line:first-child{
    width: 50%;
    /* 设置变换的基点 */
    transform-origin: right;
    /* 过渡效果 */
    transition: transform 0.3s ease-in-out;
}
.menu-button .line:last-child{
    width: 50%;
    align-self: flex-end;
    transform-origin: left;
    transition: transform 0.3s ease-in-out;
}
/* 菜单列表 */
.menu-list{
    width: 140px;
    height: 160px;
    background-color: #fff;
    border-radius: 8px;
    list-style: none;
    padding: 6px;
    box-shadow: 0 0 4px 4px rgba(92,103,255,0.15);
    position: absolute;
    right: 15px;
    bottom: 15px;
    /* 默认隐藏 */
    opacity: 0;
    transform: scale(0);
    /* 设置变换的基点 */
    transform-origin: bottom right;
    /* 过渡效果 */
    transition: 0.3s ease;
    /* 过渡延迟 */
    transition-delay: 0.1s;
}
/* 菜单项 */
.menu-list li{
    display: flex;
    align-items: center;
    padding: 10px;
    color: #1c3991;
    cursor: pointer;
    position: relative;
    /* 默认隐藏 */
    opacity: 0;
    transform: translateX(-10px);
    transition: 0.2s ease-in;
}
.menu-list li:hover{
    color: #5c67ff;
}
/* 菜单项下边框 */
.menu-list li::before{
    content: "";
    width: calc(100% - 24px);
    height: 1px;
    background-color: rgba(92,103,255,0.1);
    position: absolute;
    bottom: 0;
    left: 12px;
}
/* 最后一项不用下边框 */
.menu-list li:last-child::before{
    display: none;
}
/* 菜单项图标 */
.menu-list .fa{
    font-size: 18px;
    width: 18px;
    height: 18px;
    display: flex;
    justify-content: center;
    align-items: center;
}
/* 菜单项文本 */
.menu-list span{
    font-size: 14px;
    margin-left: 8px;
}
/* 活动态下的部分样式变化 */
/* 三条杠的变化 */
.active .line-box{
    transform: rotate(-45deg);
}
.active .line-box .line:first-child{
    transform: rotate(-90deg) translateX(1px);
}
.active .line-box .line:last-child{
    transform: rotate(-90deg) translateX(-1px);
}
/* 菜单列表的变化 */
.active .menu-list{
    opacity: 1;
    transform: scale(1);
}
.active .menu-list li{
    /* 执行动画：动画名 时长 线性 停留在最后一帧 */
    animation: fade-in-item 0.4s linear forwards;
}
/* 接下来为每一项设置动画延迟时间 */
.active .menu-list li:nth-child(1){
    animation-delay: 0.1s;
}
.active .menu-list li:nth-child(2){
    animation-delay: 0.2s;
}
.active .menu-list li:nth-child(3){
    animation-delay: 0.3s;
}
.active .menu-list li:nth-child(4){
    animation-delay: 0.4s;
}

/* 定义动画 */
@keyframes fade-in-item {
    100%{
        transform: translateX(0);
        opacity: 1;
    }
}