My blog is using the Vigilance theme. When editing a post, the font sizes for H1, H2 etc seem to be correct. But when I publish the post, H1 ends up being smaller than H2. Actually all of these element sizes are smaller, but not as bad as H1.
The styling of headings on Vigilance is highly unusual. If you had the Custom Design upgrade you would be able to change it once for all. Without the upgrade you can only change each heading manually. Switch the editor to “Text”, turn this: <h1>
to this: <h1 style="font-size:100%;">
and increase the percentage.