Changing text back to Blackbird theme's default

When volunteering to help a friend with her site someone else set up and that uses the Blackbird theme, she asked about some text color changes being possible. I don’t remember what I did but it made the body text change to lavender on all the pages. (This was before a child theme and a backup option had been set up.) I went to each page to modify the color of the text back to black, but one page will not allow the text to be changed to any other color.
http://www.rhetaministries.org/we-believe/
Adding a new page with the intent of deleting the lavenderd one seemed to work when viewing the preview, but after adding more text, its text too went lavender.
Can anyone please help me figure out how to get this page to function normally again? Will this inadvertent custom color be retained even when upgrading to the pro version of Blackbird?