But it’s not the issue, is it?
I’m not too sure tbh at a quick glance, but i’d change them first just to ensure that it doesn’t interfere.
If the headings are only ever going to be on one-line you could use line-height to vertically center them, e.g line-height:30px;
Out of interest, why does it only go up to 6? Seems sort of odd.
Well because there would never really be a need to go beyond this, if you think of how headings work:
<h1>Master Heading</h1>
<h2>Sub-Heading 1.1</h2>
<h3>Sub-Sub Heading 1.1.1</h3>
<h4>Sub-Sub-Sub Heading 1.1.1.1</h4>
<h4>Sub-Sub-Sub Heading 1.1.1.2</h4>
<h3>Sub-Sub Heading 1.1.2</h3>
<h4>Sub-Sub-Sub Heading 1.1.2.1</h4>
<h4>Sub-Sub-Sub Heading 1.1.2.2</h4>
<h2>Sub-Heading 1.2</h2>
<h3>Sub-Sub Heading 1.2.1</h3>
<h4>Sub-Sub-Sub Heading 1.2.1.1</h4>
<h4>Sub-Sub-Sub Heading 1.2.1.2</h4>
<h3>Sub-Sub Heading 1.2.2</h3>
<h4>Sub-Sub-Sub Heading 1.2.2.1</h4>
<h4>Sub-Sub-Sub Heading 1.2.2.2</h4>
As a basic example, the document would have to be very detailed to end up needing a h7 heading.