What to change the Text color of my Apps name.

[HanselTita]

When i run my apps, the name is displayed in black and every upcoming activity also displays in black. i want to display it in black.

I tried this set it white: #F5F8F8 in my colors.xml

and @color/textColorPrimary

but that changes all the text that ever appears in my apps. Which is not what i want. I want only the apps name and names of Acitivities to be white.
Should I change all the "Apptheme"