So, say you like a particular Theme in Google Presentation, but not the color. Well, that is an easy fix!
1. Choose the desired Theme. For this example, I chose ‘Label’.
2. Just above the slide, there is a toolbar. One of the options is ‘background’. (NOTE: be sure that the slide is selected – on left – NOT a space on the actual slide, otherwise you will not be able to see this option.)
3. A pop-out window will appear. This is where you can select a new color.
4. Select ‘Apply to all’ in order to have a uniform looking presentation. Then select the blue ‘Done’ button, and viola you have customized the Presentation Theme.