html,
body {
    margin: 0;
    width: 100%;
    height: 100vh;
}

div.bg {
    width: 100%;
    height: 100Vh;
    background-color: red;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    display: grid;
    place-items: center;
}
button.tanuki{
    background-color: transparent;
    font-size: 10rem;
    border: 0;
}