H1 H2 H3 headings wrong size.

Arlex fixed the H1 heading, which was way too big. Now the H2 and H3 heading need to be proportionate.
I don't know how to do custom css to fix this. I think the H3 is ok
This is how the feed looks like now, the title is good, but the H2 is way too big, looks weird.
example below;

https://medicalcannabis.com.au/medical-cannabis-feed-blog/airport-sets-up-amnesty-boxes-for-flyers-to-dispose-their-weed