Page background color CSS

How do I make that padded area the same grey color? This is using custom CSS that target

ed the scene background color.

In the builder go to / setting / Apy & Code / CSS
In the field that allows you to add css yo have to write this {
  background-color: #bebebe;

But replace #bebebe with the exact grey that you want to achieve. However, I don’t think that you can have different colors in different pages. If you need that, maybe you’d have to use JS.