Any Ideas to make my pages look better

No i think every page with this style is fine :)

Ok try editing this CSS:

.single .container.grid-container {
    max-width: 775px;
}

to this:

.single .container.grid-container, .page .container.grid-container {
    max-width: 775px;
}

Ok Leo, that worked but my home page changed. Sorry I only want other pages except my blog page and home page

Also I would like my other pages to be 900px width not 775px

Ok let's take a step back and summarize this.

- Home page and blog page --> default container width set in the customizer

- Single posts: 775px

- Static pages: 900px

Is that correct?

Yes that's correct Leo

So edit this CSS:

.single .container.grid-container, .page .container.grid-container {
    max-width: 775px;
}

To this in order to separate them:

.single .container.grid-container {
    max-width: 775px;
}
.page:not(.home) .container.grid-container {
    max-width: 900px;
}

Hi Leo, it still affects my home page?

Edited:
https://generatepress.com/forums/topic/any-ideas-to-make-my-pages-look-better/page/2/#post-1444467

Bada bing bada boom, thanks Leo, that seemed to have worked!

No problem :)