Adjust header width 100% (not working on firefox)

Hello,

I would like to know if you get already this issues, and how to fix it?

I need to place a costum header banner on my “genesis_header” for each page, but the banner width is bigger than the body.
The wird thing is that the issues is visible on firefox, but not on firefox dev, and either on safary and chrome..
i clean the cache and it still there..

I have put some codes on my style.css of my template:
.gch-header-image-inner {
display: inline-block;
position: relative;
max-width: 100%;
}

I know i should put it directly on the gch-front-end-front-style.css
but what will happen if when i will update the plugin?

thank you for your help ??

I choose the options:
“Display Custom Image”

The web where is the issues:
https://www.myriade.ch/

https://www.ads-software.com/plugins/genesis-custom-headers/