.all {
    width: 1200px;
}
.opBG {
    background: url(//pic.mairuan.com/WebSource/guitarpro/web/images/opBG.png);
}
.bd-r-1 {
    border-right: 1px solid #fff;
}
.a-4 {
    background: none;
    border: 1px solid #fff;
    color: #fff;
    display: inline-block;
    text-align: center;
    box-sizing: border-box;
}