body {
    background-image:url("../img/bk_10th.gif");
}

section{
    margin: 50px auto;
    text-align: center;
}
.contents_box img{
    width: 400px;
    margin: auto;
}
.contents_box div{
    background-color: #E2B7CC;
    padding: 10px;
    width: 400px;
    margin: 40px auto;
}

.contents_box p{
    margin-bottom: 20px;
}

footer{
    text-align: center;
    margin: 40px auto;
}