feat: 优化个人页面样式和颜色配置

- 更新个人页面中菜单项的背景色和图标颜色，提升视觉效果
- 调整用户信息卡片和统计项的阴影效果及边框样式，增强层次感
- 优化颜色常量，提升文本和结构色的对比度，改善可读性
- 更新背景渐变色，提供更柔和的视觉体验

app/(tabs)/personal.tsx

@@ -152,12 +152,12 @@ export default function PersonalScreen() {
           <View style={styles.menuItemLeft}>
             <View style={[
               styles.menuIcon,
-              { backgroundColor: item.isDanger ? 'rgba(255,68,68,0.12)' : 'rgba(187,242,70,0.12)' }
+              { backgroundColor: item.isDanger ? 'rgba(255,68,68,0.12)' : 'rgba(135,206,235,0.15)' }
             ]}>
               <Ionicons
                 name={item.icon}
                 size={20}
-                color={item.isDanger ? colors.danger : colors.onPrimary}
+                color={item.isDanger ? colors.danger : '#4682B4'}
               />
             </View>
             <Text style={[styles.menuItemText, { color: colorTokens.text }]}>{item.title}</Text>
@@ -336,11 +336,13 @@ const styles = StyleSheet.create({
   userInfoCard: {
     borderRadius: 16,
     marginBottom: 20,
-    shadowColor: '#000',
-    shadowOffset: { width: 0, height: 2 },
-    shadowOpacity: 0.08,
-    shadowRadius: 6,
+    shadowColor: 'rgba(135,206,235,0.3)',
+    shadowOffset: { width: 0, height: 4 },
+    shadowOpacity: 0.15,
+    shadowRadius: 8,
     elevation: 3,
+    borderWidth: 1,
+    borderColor: 'rgba(135,206,235,0.1)',
   },
   userInfoContainer: {
     flexDirection: 'row',
@@ -372,11 +374,13 @@ const styles = StyleSheet.create({
     borderRadius: 16,
     padding: 20,
     marginBottom: 20,
-    shadowColor: '#000',
-    shadowOffset: { width: 0, height: 2 },
-    shadowOpacity: 0.1,
-    shadowRadius: 4,
+    shadowColor: 'rgba(135,206,235,0.25)',
+    shadowOffset: { width: 0, height: 3 },
+    shadowOpacity: 0.12,
+    shadowRadius: 6,
     elevation: 3,
+    borderWidth: 1,
+    borderColor: 'rgba(135,206,235,0.08)',
   },
   statItem: {
     alignItems: 'center',
@@ -390,6 +394,13 @@ const styles = StyleSheet.create({
     marginBottom: 20,
     padding: 16,
     borderRadius: 16,
+    shadowColor: 'rgba(135,206,235,0.2)',
+    shadowOffset: { width: 0, height: 2 },
+    shadowOpacity: 0.1,
+    shadowRadius: 4,
+    elevation: 2,
+    borderWidth: 1,
+    borderColor: 'rgba(135,206,235,0.06)',
   },
   sectionTitle: {
     fontSize: 20,