.timer {
    width: 256px;
    margin: 0 auto;
}

.timer .digit, .timer .delimiter {
    width: 20px;
    height: 30px;
    border: 1px solid #cccccc;
    padding: 15px 5px 5px 5px;
    text-align: center;
    font-size: 32px;
    float: left;
}