.bgi {
    position: relative;
    left: 0;
    top: 0;
    width: 100%;
    height: 50vh;
    background-image: url(../Assets/Images/jianjie-banner.jpg);
    background-size: cover;
}
.contain {
    border-left: 2px solid skyblue;
    width: 750px;
    height: 2000px;
    margin-top: 20px;
}
h2 {
    display: block;
    font-weight: 600;
    line-height: 50px;
    text-align: center;
    width: 200px;
    height: 50px;
    margin-top: 40px;
}