<table class="postTable">
    <thead>
    <tr>
        <th>Kategorie</th>
        <th>Aktueller Monat</th>
        <th>Vormonat</th>
        <th>Vergleich Vormonat</th>
    </tr>
    </thead>
    <tbody>
    <tr>
        <td data-label="Kategorie">Artikel</td>
        <td data-label="April 2012">10</td>
        <td data-label="Vormonat">1</td>
        <td data-label="Vergleich Vormonat">-</td>
    </tr>
    <tr>
        <td data-label="Kategorie">Kommentare</td>
        <td data-label="April 2012">0</td>
        <td data-label="Vormonat">0</td>
        <td data-label="Vergleich Vormonat">-</td>
    </tr>
    </tbody>
</table>

@media all and (max-width:640px) {
    .postTable, .postTable thead, .postTable tbody, .postTable tr, .postTable th, .postTable td {
        display: block;
    }
 
    .postTable {
        text-align: right;
    }
 
    .postTable thead {
        position: absolute;
        top: -1111px;
        left: -1111px;
    }
 
    .postTable td:before {
        float: left;
        padding: 0 10px 0 0;
        content: attr(data-label) ":";
    }
 
    .postTable td:nth-child(1) {
        font-weight: bold;
    }
 
    .postTable td:nth-child(1) {
        font-weight: bold;
    }
 
    .postTable td:last-child {
        border-bottom: 5px #d4e7ee solid;
    }
}