Change the blog post container

Hi

I recently installed the theme Generatepres on my WP Site and everything is going great except changing the blog post container size.

I have tried following the support that was given in this topic: https://generatepress.com/forums/topic/change-blog-posts-container-width/ but unfortunally I cant make it work on my site.

I would like to increase the size of each page of the blog because my GoPricing plugin is a bit to small to show the whole text on desktop. Here hos it looks now https://imgur.com/a/bVbHpBH

On mobilephone everything is perfect as it is.

What have I tried?

1. Going to Apperance -> Customize -> Layout -> Container and tried increasing it from 1100px to 1250 px but it only affect the first page of the website.

2. Added the .single-post #content {
max-width: 1250px;
} with no result.

What is my final goal of this support request?
To have the firstpage as 1100px container and the blogpost pages as 1250 px so the GoPricing plugin doesnt shrink.

Thank you so much
Best regards