A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
On the Design tab of the ribbon in the Variants group, click the downward-pointing triangle.
In the Gallery that appears, click Colors then choose Customize Colors.
That opens the dialog where you can edit the theme colors for the presentation.
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When pasting from one presentation to another, you usually have the option to keep source formatting or apply the formatting of the presentation you're pasting slides into. Choosing to keep source formatting might be the answer to the problem as well.