body {
    margin: 0;
    overflow: hidden;
    font-family: Arial, sans-serif;
}

#altitude, #score, #crash {
    position: absolute;
    padding: 8px;
    background-color: rgba(0, 0, 0, 0.5);
    color: #fff;
    z-index: 9999;
}

#altitude {
    top: 10px;
    left: 10px;
}

#score {
    top: 50px;
    left: 10px;
}

#crash {
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    display: none;
}

#planeSelection {
    position: absolute;
    top: 10px;
    left: 150px;
    z-index: 9999;
}

#planeSelection button {
    display: block;
    margin-bottom: 10px;
    padding: 5px 10px;
    cursor: pointer;
}