Has anyone built an ArcGIS Dashboard that vertically aligns a List Widget within the box? I have tried all sorts of HTML in the Advanced formatting, I have tried the JSON in the Assistant and I have not found any technique that achieves dynamic centering across multiple screen sizes.

Here is my existing Source code
<p style="text-align:center;">
<strong>Average Dwell Time</strong>
</p>
<h2 style="margin:0;text-align:center;">
<span style="color:hsl(238,72%,63%);font-size:24px;"><strong>{field/avg_dwell_time}</strong></span>
</h2>