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

#container {
    position: absolute;
    top: 0;
    left: 0;
    background: #090000;
    width: 100%;
    height: 100%;
}

#canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

button {
    position: absolute;
    left: 1em;
    bottom: 1em;
    font-size: 1.5em;
    padding: .1em;
    border: 0;
    outline: 0;
    border-radius: 100em;
    width: 2em;
    height: 2em;
    cursor: pointer;
}

button#musicInputBtn {
    position: absolute;
    bottom: 1em;
    right: 1em;
    left: calc(100vw - 1em - 2em);
    font-size: 1.5em;
    padding: .1em;
    border: 0;
    outline: 0;
    border-radius: 100em;
    width: 2em;
    height: 2em;
    cursor: pointer;
}