Sales page layout

Hi there,

Sorry I'm not quite sure what I'm looking at? The screenshot is just a white blank page.

Let me know.

What I mean is a single body layout with the rounded corners and shadow effect around the border.

You could do this: https://docs.generatepress.com/article/adding-a-container-wrapper/

.full-container {
    background:#FFF;
    border-radius: 10px;
    box-shadow: 0 0 5px 5px rgba(0,0,0,0.1);
}

Thanks for the code Leo.

Is the code for using this on a single page only where all the other pages have a different layout?

No, you would have to add that CSS to the individual page using my Simple CSS plugin to achieve that.