To make your PHCorner theme black, you can follow these steps:
1. Log in to your PHCorner account.
2. Click on your username on the upper right-hand corner of the page.
3. Select "My Account" from the drop-down menu.
4. Under the "General Settings" tab, click on "Board Preferences."
5. Look for the "My Board Style" option and select "Black Pearl" from the drop-down menu.
6. Click on the "Submit" button at the bottom of the page to save your changes.
Once you've completed these steps, your PHCorner theme will be black.