body {
    width: 90%;
    margin: 0 auto;
}
header {
    margin-top: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid #b5b5b5;
}
.logo {
    width: 250px;
    height: 150px;
    text-align: center;
}

img {
    display: block;
    margin-right: auto;
    margin-left: auto;
}