App Interface Guideline: Typography — Dynamic Type Support. Keywords: allowFontScaling adjustsFontSizeToFit. Platform: iOS/Android/React Native. Description: Support system text scaling without breaking layout. Do: Set allowFontScaling and test large text. Don't: Disable scaling on all text globally. Good Example: <Text allowFontScaling>{label}</Text>. Bad Example: <Text allowFontScaling={false}>{label}</Text>. Severity: High.