This is a "Details" block with the "Outline" style

You can add whatever blocks you need within each details block.

Here is a Button
You can change both the background color and the text color

Each of these is using Lovers Lane for the background (outline) color and Oval Green for the text color.

With the details block active, navigate to the panel to the right, then click the "Styles" tab to change colors. Be sure to apply the same styles to all Details blocks in a group for consistency.

This details block has a "Cover" block within it

The "Details" blocks are intended to be flexible, and to make large sections of content easier to navigate.