fluid row, default content width

Hi.

But it works like you want by default. sppb-row-container is a container where your contents are located. It is centered and has a certain width at the breakpoints according to the Bootstrap documentation. The section is its parental element and has a full width.

Just don't switch row to full width.

To make border-bottom 1px for section CSS should be used.

Add your own class name in section settings.

Use css.

.my-section {
    border-bottom: 1px solid #000;
}

And you will get it

As soon as I set row=full width, the content is also extended. In a competitor's builder I can set row=full width; content=boxed (default). Thus I can use the interface to design the full width row; background, border, overlay, that the boxed content sits in.
If I also want content=full width, I set that by the custom container settings.

You must understand that many of us are designing for clients who don't know css or the importance of class names. If it is possible to customise using the 'standard' interface tools, that should be a priority.

We are told to design for mobile first.
You should design for noobie first.

You must understand that many of us...

I am not Joomshaper team member. I just advised you a solution that you can use.

I also work with clients. And from my practice, after I develop the site using classes and CSS, the client never touches this again. He/She just does not need it. The maximum that client do after my development is changing content. Or copies the blocks that I set up