.four{
    width: 738px;
    height:505px;
    margin:0 auto;
    margin-top: 35px;
}
h2.aa{
    font-size: 30px;
    font-family: 黑体;
    text-align: center;
    color:#919191;
}
.nes{
    width:450px;
    margin:0 auto;
    overflow: hidden;
    font-size: 24px;
    color:#919191;
    line-height: 58px;
    margin-top: 30px;
}
.nes .p1{
    float: left;
}
.nes .p2{
    float: left;
    width:300px;
}
.btn{
    width:407px;
    height:66px;
    margin:0 auto;
    margin-top: 58px;
}
.btn button{
    width:158px;
    height:66px;
    border-radius: 5px;
    font-size: 24px;
    color:#fff;
}
.btn1{
    background: #f5883b;
    float:left;
    cursor: pointer;
}
.btn2{
    background:#2a77e6;
    float:right;
    cursor: pointer;
}