H1 header is smaller than H2 in docs pages -- broken CSS?

[stichbury]

For some reason we are seeing H1 on pages in the docs looking smaller than H2 (see https://docs.kedro.org/en/stable/tutorial/spaceflights_tutorial.html for an example). I don't know why this is or when it started but it seems OK in Kedro 0.18.0 https://docs.kedro.org/en/0.18.0/tutorial/spaceflights_tutorial.html

Would it be possible to investigate further please?

Edit to note: Also H3 looks to be only marginally smaller than H2.

I should also note that we are likely to make some more far-reaching changes to the docs design in the near-ish future so this shouldn't turn into a major revision of the CSS (however ugly it is) and if it looks like a big chunk of work, we can live with it for now!

[tynandebold]

I can have a look.

Can I move this ticket to the Kedro repo, since that's where the code change would occur?