Hook one content-div inside second all-width div

Hi there,

any reason not to use the Header Element - which does that kind of thing?
https://docs.generatepress.com/article/header-element-overview/

If no good then use after_header hook.

You Markup would look something like this:

<div class="green-wrap">
    <div class="blue-container grid-container">
        <!-- markup in here -->
    </div>
</div>

The hook will automatically fit 100% wide.
The grid-container class is a GP Class and will size the green container to match the sites container size.