* {
    box-sizing: border-box;
    text-rendering: optimizeLegibility;
    font-kerning: auto;
    outline: 0 !important;
}

html {
    font-family: sans-serif;
}

body {
    margin: 0;
    overflow: hidden;
    background: #f1f1f1;
}

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

#app {
    position: relative;
}

header {
    height: 30px;
    width: 640px;
    background: #444;
    color: #fefefe;
    position: absolute;
    top: 4px;
    left: calc(50% - 320px);
    padding: 0 8px;
    line-height: 30px;
    font-size: 12px;
}

header > div {
    float: right;
}

#canvas {
    width: 640px;
    height: 480px;
    position: absolute;
    top: 34px;
    left: calc(50% - 320px);
}