body, html {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
}

#gameCanvas {
    width: 100vw;
    height: 100vh;
    display: block;
    margin: auto;
}

#mobileKeypad {
    display: none;
    position: fixed;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    width: 200px;
    height: 200px;
    z-index: 1000;
}

#mobileKeypad button {
    position: absolute;
    width: 60px;
    height: 60px;
    background-color: rgba(255, 255, 255, 0.2);
    border: 2px solid rgba(0, 0, 2505, 0.2);
    border-radius: 50%;
    font-size: 24px;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    user-select: none;
}

#upBtn { top: 0; left: 50%; transform: translateX(-50%); }
#leftBtn { top: 50%; left: 0; transform: translateY(-50%); }
#rightBtn { top: 50%; right: 0; transform: translateY(-50%); }
#downBtn { bottom: 0; left: 50%; transform: translateX(-50%); }

@media (max-width: 768px), (pointer: coarse) {
    #mobileKeypad {
        display: block;
    }
}