Gap between sections and between menu and content and...

Hi ! I did buy yesyerday the agency generate block etc.. I use generatepress+premium.

I have a BIG prblem, let me explain, it can be seen here. My little mess ;-)

I would like to get rid of the space between the top bar (with my menu) and the first content (a bloc). I did in the option of the page choose to hide the title of the page but as you can see, there is still a gap show the inde container in white and the gray background. Always have this puzzle with generate press (getting rid of this famous gap between section, before footers, under block, etc...

Best regards !

Martin