Hi Christine,
Thank you for reaching out and thanks for using Crio Pro WordPress theme!
Sorry to hear you’re having trouble changing the background color of one of your blocks. I inspected your page and it looks like that particular block has it’s own CSS appended to it. If you select the column instead of the section itself you should allow you to access its color controls.
When you hover over the block you should see a blue tab above your first column? Click the toggle icon and select “Change Background” it will give you the option to change the background properties for that individual column.
I hope this helps. Please reach back out if you have any other questions for us.