For any theme (both the Mentimeter default themes and the ones you’ve created), you can also style individual slides if you’re on a Pro, Conference, or Teams plan.
To do this, select your slide in the Overview panel to the left and then select the 'Design' tab. Now, you can add a background color or upload a background image. You can also change text, line, and visualization colors to customize the look of your slide.
Please note: These changes will be reflected in your presentation view only. The styling that is added to individual slides will not be reflected in the voting device's view.