When reading a PDF file at night for a long time, the overwhelming brightness may hurt your eyes, PDF Reader Pro can solve this annoying problem. The following are the steps to change PDF themes:
1. Click Page Display 
on the toolbar -> find Theme in the right panel;
2. There are 4 different themes for you to choose: Light, Sepia, Dark, and Reseda;
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Light Mode: The default one that displays the document on a bright white background.
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Sepia Mode: Displays the document in a light-yellow background, so it’s easier on your eyes.
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Dark Mode: Displays the document in inverse color (like it is on film negatives) in a dark environment.
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Reseda Mode: Displays the document in a light-green background to protect your eyes after long-time reading.
3. Or you can customize the color according to your preferences, click More -> choose a color or click More -> tap Set Custom Colors -> choose a color and click Add to Custom Color -> click OK -> tap the new theme to change the PDF theme.
Download PDF Reader Pro for free to enjoy a smoother PDF reading experience now!
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