* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
html, body {
    width: 100%;
    height: 100%;
    overflow: hidden;
    background: #000;
    font-family: 'Courier New', monospace;
}
#gameCanvas {
    display: block;
    width: 100%;
    height: 100%;
    outline: none;
}