To change the color of the background of a specific Homepage Block
Log in to your website dashboard.
Click on the "Edit Site" tab located on the left-hand side section.
Navigate to the block you wish to modify, hover over it to see a pencil icon, then click on it.
Click on the "Edit Design" tab.
Locate the 'Background Style' option and click on the dropdown arrow.
Choose the Solid Option, a selector will appear below, you can use it to pick your desired color.
Press the "Save Styles" button to apply your changes.