reducing big title height for Hestia theme

I am trying to reduce the height of my “big title section” (I am using Hestia free theme).

I have found many tips on how to shift elements such as buttons, text or change the font… But only this post seems to mention a way to expand the big title section while I am trying to shrink it.

Here is the proposed additional css code from this link:

.home .page-header{
height: 100vh !important;
}

Based on the above link, I tried to modify the css code “50vh” for instance but it seems that the provided additional css code can only enlarge the big title section…

Would you have any idea of a suitable additional css code to do this ?

The page I need help with: [log in to see the link]