.tab{ width: 80%; margin: 45px auto 0;justify-content:space-between; }
.tab > a { 
	font-size: 20px;
    padding: 10px;
    text-decoration: none;
    color: #255d7e;
    border: 2px solid #5395b4;
    background: #fff;
    line-height: 50px;
    width: 12.7%;
    float: left;
    text-align: center;
}

.pic { position: relative; overflow: hidden; width: 78.125vw; height: 87.4vh; margin: 0 auto; background: #fff; box-shadow: 0 0 30px 0 rgba(8, 1, 3, .3); }