html, body {
    margin: 10;
    padding: 10;
}

.grid {
    display: flex;
    flex-wrap: wrap;
    width: 420px;
    height: 420px;
    border: solid black;
}

.grid div {
    width: 15px;
    height: 15px;
}

.pac-dot {
    background-color: green;
    border: 5px solid white;
    box-sizing: border-box;
}

.wall {
    background-color: blue;
}

.power-pellet {
    background-color: green;
    border-radius: 7.5px;
}

.pacman {
    background-color: yellow;
    border-radius: 7.5px;
}