Modifying markdown to html interpretation

Hi,
How can I modify the way grav translate markdown to html ?
I mean my markdown files contains many H1 and h2 headers. And i'd to translate them to h4 and h5.
Thanks for your help.

mmm, i don't undestand why you wanna change this, you can change your md file with # title to #### title :)

I'm a little confused also. If you have h1, h2 headers but you want to render them smaller, simply override the font-size via CSS.

If you want to physically have them output as <h4> and <h5> tags, simply change the markdown to use the h4 and h5 tags: #### h4 and ##### h5.