You can still change the overall template theme after your slides are generated. Click Switch Template at the top right and pick a new theme from the template library to apply to the current deck. In Image mode, you can also use a custom template you have already uploaded.
1. Click Switch Template
Open the template switcher at the top right of the editor.
2. Choose a library theme or a custom template
Pick a visual theme that fits the occasion, your brand guidelines and your audience.
3. Check the key pages
After switching, look closely at the cover, data pages, dense text-and-image pages and the conclusion to make sure the hierarchy and the message stay clear.