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

    text-decoration: none;
}

html,
body {
    width: 100%;
    height: 100%;
}

body {
    display: flex;
    flex-direction: column;
    justify-content: stretch;
}

div#content {
    flex: 1 1 0;
}

div#content > div {
    position: absolute;
    top: 0;
    left: 0;
    padding: 10px;
    z-index: 1000;
}

div#content > div > * {
    margin: 10px;
}

div#content > canvas {
    width: 100%;
    height: 100%;

    position: absolute;
    top: 0;
    left: 0;
    flex: 1 1 0;
}