.middle-content{
    width: 1200px;
    /*margin: 50px auto;*/
    text-align: center;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);

}
.middle-content h2{
    font-size: 32px;

}
.demo-list{
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    margin-top: 50px;
}
.demo-item{
    width: 22%;
    margin-right: 20px;
}
.demo-title{
    font-size: 16px;
    color: #151515;
    font-weight: 600;
    line-height: 25px;
    margin: 15px 0;
}
.demo-img{
    width: 100%;
}
.demo-btn{
    display: inline-block;
    width: 150px;
    height: 45px;
    line-height: 45px;
    background-color: #eaeaea;
    border-radius: 4px;
    font-size: 14px;
    margin-right: 20px;
}
.demo-edit{
    background: #6044ff;
    color: #fff;
}
.button-area{
    margin-top: 40px;
}
@media (max-width:1300px) {
    .middle-content{
        width: 1000px;
    }
}