.container{
    /* 弹性布局 */
    display: flex;
    /* 允许换行 */
    flex-wrap: wrap;
    /* 将元素靠边对齐 */
    justify-content: space-around;
}
.container .btn{
    position: relative;
    width: 200px;
    height: 60px;
    margin: 30px;
}
.container .btn a{
    /* 绝对定位 */
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    /* 透明度为0.05的白色背景 */
    background: rgba(255,255,255,0.05);
    /* 阴影 */
    box-shadow: 0 15px 35px rgba(0,0,0,0.2);
    /* 上下边框 */
    border-top: 1px solid rgba(255,255,255,0.1);
    border-bottom: 1px solid rgba(255,255,255,0.1);
    /* 圆角 */
    border-radius: 30px;
    color: #fff;
    z-index: 1;
    font-weight: 400;
    /* 字间距 */
    letter-spacing: 1px;
    /* 去下划线 */
    text-decoration: none;
    /* 动画过渡 */
    transition: 0.5s;
    /* 溢出隐藏 */
    overflow: hidden;
    /* 背景模糊 */
    backdrop-filter: blur(15px);
}
.container .btn:hover a{
    letter-spacing: 5px;
}
/* 制作扫光效果 */
.container .btn a::before{
    content: "";
    /* 绝对定位 */
    position: absolute;
    top: 0;
    left: 0;
    width: 50%;
    height: 100%;
    /* 渐变背景 透明到白色 */
    background: linear-gradient(to right,transparent, rgba(255, 255, 255, 0.15));
    /* 沿X轴倾斜45度，向右平移0像素 */
    transform: skewX(45deg) translateX(0);
    transition: 0.5s;
}
.container .btn:hover a::before{
    /* 沿X轴倾斜45度，向右平移200% */
    transform: skewX(45deg) translateX(200%);
}
/* 制作按钮上下两个发光层 */
.container .btn::before,
.container .btn::after{
    content: "";
    /* 绝对定位，横向居中 */
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 40px;
    height: 10px;
    /* 自定义颜色属性--c, 可通过var函数调用 */
    /* --c: gold; */
    background: var(--c);
    border-radius: 5px;
    box-shadow: 
        0 0 5px var(--c),
        0 0 15px var(--c),
        0 0 30px var(--c),
        0 0 60px var(--c)
    ;
    transition: 0.5s;
}
.container .btn::before{
    bottom: -5px;
}
.container .btn::after{
    top: -5px;
}
.container .btn:hover::before,
.container .btn:hover::after{
    height: 50%;
    width: 80%;
    border-radius: 15px;
    transition-delay: 0.3s;
}
.container .btn:hover::before{
    bottom: 0;
}
.container .btn:hover::after{
    top: 0;
}
/* 分别设置自定义颜色属性--c */
.container .btn:nth-child(1)::before,
.container .btn:nth-child(1)::after{
    --c: #e91268;
}
.container .btn:nth-child(2)::before,
.container .btn:nth-child(2)::after{
    --c: #e94412;
}
.container .btn:nth-child(3)::before,
.container .btn:nth-child(3)::after{
    --c: #1261e9;
}
.container .btn:nth-child(4)::before,
.container .btn:nth-child(4)::after{
    --c: #39e912;
}