body {
    margin: 0;
    padding: 0;
    background-color: black;
}

section {
    margin: 0 auto;
    width: 350px;
    height: 650px;
    box-sizing: border-box;
    background-color: white;
    overflow: auto;
}

h1, h2 {
    font-weight: bold;
}

h1, h2, p {
    margin: 10px 0;
}

.tiles {
    width: 350px;
    height: 350px;
    position: relative;
    background-repeat: repeat;
}

.tile {
    width: 50px;
    height: 50px;
    position: absolute;
    left: 0;
    top: 0;
}