Vertically and horizontally center two lines of text

[niche1]

I know vertical-align works great on one line of text, but I can't get this script to vertically (and horizontally) center two lines of text. What do I need to do change without changing the size of the div?

echo '<div style="float:left;width:171px;height:96px;text-align:center;display:table-cell;vertical-align:text-middle;background-color:yellow;">';
echo '<h1 >1/35 Scale House</h1>';
echo '</div>';

[niche1]

This does the trick:

echo '<div style="float:left;">';
echo '<h1 style="display:table-cell;vertical-align:middle;width:171px;height:96px;text-align:center;">1/35 Scale Panther</h1>';
echo '</div>';