diff --git a/components/onboarding/ui/PrimaryButton.tsx b/components/onboarding/ui/PrimaryButton.tsx
index 50fc3f1..d055c70 100644
--- a/components/onboarding/ui/PrimaryButton.tsx
+++ b/components/onboarding/ui/PrimaryButton.tsx
@@ -23,7 +23,9 @@ export function PrimaryButton({ label, active = true, onPress, loading = false }
 
 const styles = StyleSheet.create({
   btn: { height: 50, borderRadius: 12, alignItems: 'center', justifyContent: 'center' },
-  btnActive: { backgroundColor: colors.primary },
+  // 按钮底色用 primaryBtn 而非 primary：白字对比 4.8:1 过 WCAG AA，
+  // primary 作白字底只有 3.64:1，不满足 AA（见 AGENTS.md 配色规范）
+  btnActive: { backgroundColor: colors.primaryBtn },
   btnDisabled: { backgroundColor: colors.textDisabled },
   btnText: { fontSize: 17, fontWeight: '700', color: colors.textInverse },
 });