style.css

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

#main {
    height: 420px;
    width: 360px;
    border: 10px #000 solid;
    background-color: #b7d4a8;
    border-radius: 20px;
    margin: 50px auto;
}

#stage {
    width: 304px;
    height: 304px;
    border: 2px solid #000;
    margin: 20px auto;
    position: relative;
}

#snake > div {
    width: 10px;
    height: 10px;
    background-color: #000;
    position: absolute;
    border: 1px solid #b7d4a8;
}

#food {
    width: 10px;
    height: 10px;
    position: absolute;
    top: 100px;
    left: 120px;
    display: flex;
    flex-flow: wrap;
}

#food > div {
    width: 5px;
    height: 5px;
    background-color: #000;
    transform: rotate(45deg);
}

#info {
    width: 304px;
    margin: 0px auto;
    display: flex;
    justify-content: space-between;
    font: bold 20px courier;
}