How to Change Power BI Application Theme from Dark to Light 

If your Microsoft Power BI interface is in Dark Mode and you want to switch it back to Light Mode, you can change it from the application settings.

Steps to Change Power BI Theme (Dark → Light)

1. Open Power BI Desktop.

2. Click File in the top menu.

3. Select Options and Settings.

4. Click Options.

5. In the Global section, select Report Settings.

6. Look for Customize Appearance 

7. Change it from Dark to Light.

8. Click OK.

9. Restart Power BI Desktop if required.

After that, the interface will switch to the light theme.