Strich durch Zahlen

HTML

<p class="countdown">
    <!-- Noch --> <span class="countdown-number">2</span>
 <span class="countdown-number">7</span>
 <span class="countdown-number">4</span> &nbsp;Tage…</p>

CSS

.countdown {
    margin-top: 1em;
}
.countdown-number {
    color: #fff;
    background: #444;
    border-top: 2px solid #000;
    border-right: 2px solid #fff;
    border-bottom: 2px solid #fff;
    border-left: 2px solid #333;
    /*  text-decoration: line-through; */
    font-size: 3em;
    line-height: .9;
    display: inline-block;
    margin-left: 5px;
    font-family: Courier;
    /* neu */
    position: relative;
}
.countdown-number:before {
    content:"";
    display: block;
    height: 1px;
    width: 100%;
    background: #fff;
    position: absolute;
    top: 50%;
    left: 0;
}