game-of-life.css

body {
    font-size: 14pt;
    font-family: Helvetica, Verdana, "Bitstream Vera Sans", "Hiragino Sans GB", "LiHei Pro", STHeiti, "Microsoft YaHei", SimHei, "WenQuanYi Micro Hei", Sans-serif;
    float: left;
    width: 100%;
    padding: 0;
    margin: 0;
    color: #111;
    background-color: #EFEFEF;
}

a:link, a:active {
    text-decoration: none;
    color: #0099FF;
}

a:visited {
    color: #0066FF;
}

#container {
    float: left;
    width: 100%;
}

#header {
    float: left;
    width: 100%;
    background-color: #333;
    margin: 0;
    padding: 0;
    text-align: center;
}

    #header h1 {
        margin: 2em 0 0;
        color: #EEE;
    }

    #header p {
        color: #CCC
    }

#subtitle {
    margin: 0 auto 1em;
}

#author {
    margin: 0 auto 5em;
}

#body {
    clear: left;
    float: left;
    width: 100%;
    margin: 0;
    padding: 0;
}

    #body h2, h3 {
        width: 960px;
        margin: 2em auto 1em;
    }

    #body h2 {
        color: #444;
    }

    #body h3 {
        color: #333;
    }

    #body p {
        width: 960px;
        margin: 1em auto;
    }

    #body p.emphasis {
        text-align: center;
        font-size: 1.5em;
    }

.game-of-life {
    margin: 1em auto;
    padding: 1em;
}

.game-of-life-control-panel button {
    text-align: center;
    margin: 0 0.5em 1em;
    padding: 0.5em 1em;
}

.game-of-life div {
    text-align: center;
}

.game-of-life .x {
    visibility: hidden;
}

.game-of-life .x-container {
    display: inline-block;
    margin: 1px;
    height: 30px;
    width: 30px;
}

.game-of-life .x-live {
    background-image: url('happy-cat-face.png');
    background-position: 0 0;
    border: 1px solid transparent;
}

.game-of-life .x-dead {
    border: 1px solid #DDD;
}

#footer {
    float: left;
    width: 100%;
    clear: left;
    background-color: #666;
    margin: 0;
    padding 0;
}

    #footer h2 {
        width: 960px;
        margin: 2em auto 0;
        color: #BBB;
    }

    #footer p {
        width: 960px;
        color: #CCC;
        margin: 1em auto 5em;
    }

    #footer a:link, #footer a:active {
        color: #00CCFF;
    }

    #footer a:visited {
        color: #00AAFF;
    }

.y {
    line-height: 0;
    margin: 0;
    padding: 0;
}