Only one of mulitple style attributes is rendered

[GrazingScientist]

When having something like

<table>
    <td id="table-cell-1234" align="center" style="background-color: royalblue">ABC</td>
</table>

In the HTML, only the text-align: center is realized in my table. The color is ignored. However, I would expect that both attributes are stacked to give the final style.

The problem is that the add-style template in the XSLT does not acknowledge any already present style attributes. Can this be realized?