Logoduk
I can't change text colour directly — that's a design setting in the theme editor, not a text block function.
To make text black in your header:
1. Click the text block you want to change
2. Look for a "Text colour" or "Colour" option in the right panel
3. Select black from the colour picker
If you don't see a colour option, check that you're editing the right element — some header elements have colour settings at the section level rather than the block level.