1. Open the iTunes app on your Mac.
2. From the menu bar at the top of the screen, click on "iTunes" > "Preferences."
3. In the "Preferences" window, click on the "General" tab.
4. Under the "Appearance" section, you will see a drop-down menu for "Background."
5. Click on the drop-down menu and select the desired background color from the options available.
6. Click on the "OK" button to save the changes and close the "Preferences" window.
To change the background color of iTunes on a Windows PC:
1. Open the iTunes app on your Windows PC.
2. From the menu bar at the top of the window, click on "Edit" > "Preferences."
3. In the "Preferences" window, click on the "General" tab.
4. Under the "Appearance" section, you will see a drop-down menu for "Background Color."
5. Click on the drop-down menu and select the desired background color from the options available.
6. Click on the "OK" button to save the changes and close the "Preferences" window.
Note: The steps to change the background color of iTunes may vary depending on the version of iTunes that you are using.