Categories and sub-categories style for FAQ

In the website, we need to create FAQ pages with categories and sub-categories similar to the fieldsets module in Drupal 7. For this purpose, we used the FAQ Accordion style and I was able to create the categories and sub-categories and group the items accordingly. However, I would like to change the style of the categories and sub-categories title to for example (h2 and a certain color). Could you please help me with this?
The page in question is : and I would like to make the category (e.g. Excellent Science in h2 and blue) and then sub-category (e.g. European Research Infrastructures) in h4 and black.

Thank you in advance,

Dear Livia,

There is not an out of the box solution for what you ask.

The only way to change the colours of the categories is with JS code but it’s not worth it to get in such trouble.

Dear Sotirios,

Thank you for having looked into this. In the meantime, we have found a solution by creating multiple content types and multiple views and then putting them together in a landing page.