Text color become grey instead of pure black when create APK build

Hi,

Currently, I am developing react native app using Expo CLI on Bare Workflow. When I try to change android:textColor in android/app/src/main/res/values/styles.xml the text color stays the same. I want to change this because when I build the project to APK, the text color becomes grey instead of pure black.

Thank you in advance for helping.