*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
.back{
    background: url("image/banner.jpg");
    position: relative;
    background-position:  center;
    background-size: cover;
    width: 100vw;
    height: 100vh;
}
.head{
    background-color: rgba(14, 13, 13, 0.5);
    width: 100%;
    height: 100%;
    position: absolute;
}