diff --git a/app/src/main/java/com/zcshou/gogogo/OfflineMapActivity.java b/app/src/main/java/com/zcshou/gogogo/OfflineMapActivity.java
index 10c8da6..56feeda 100644
--- a/app/src/main/java/com/zcshou/gogogo/OfflineMapActivity.java
+++ b/app/src/main/java/com/zcshou/gogogo/OfflineMapActivity.java
@@ -6,9 +6,13 @@ import androidx.fragment.app.FragmentActivity;
 import androidx.fragment.app.FragmentStatePagerAdapter;
 import androidx.viewpager.widget.ViewPager;
 import android.util.Log;
+import android.view.View;
+import android.widget.ImageButton;
 
 public class OfflineMapActivity extends FragmentActivity {
 
+    ImageButton btnBack;
+
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         Log.d("OfflineMapActivity", "onCreate");
@@ -22,10 +26,19 @@ public class OfflineMapActivity extends FragmentActivity {
         viewPager.setAdapter(pagerAdapter);
 
         TabLayout tabLayout = findViewById(R.id.sliding_tabs);
+        tabLayout.setTabGravity(TabLayout.GRAVITY_CENTER);
         tabLayout.setupWithViewPager(viewPager);
         tabLayout.setTabMode(TabLayout.MODE_FIXED);
+        btnBack = findViewById(R.id.back);
+        // btnBack.setImageResource(R.drawable.ic_run);
+
     }
-    
+
+    public void goHome(View view) {
+        this.finish(); // back button
+    }
+
+
     @Override
     public void onDestroy() {
         Log.d("OfflineMapActivity", "onDestroy");
diff --git a/app/src/main/res/drawable/ic_back.xml b/app/src/main/res/drawable/ic_back.xml
new file mode 100644
index 0000000..1a83012
--- /dev/null
+++ b/app/src/main/res/drawable/ic_back.xml
@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="128dp"
+    android:height="128dp"
+    android:viewportWidth="1024"
+    android:viewportHeight="1024">
+  <path
+      android:fillColor="#FF000000"
+      android:pathData="M941.3,553.2 L240.41,553.2l347.2,347.2 -58.26,58.26L82.7,512 529.35,65.35l58.26,58.26 -347.2,347.2 700.89,0L941.3,553.2zM199.22,512l0.57,0.57 0,-1.14L199.22,512z"/>
+</vector>
diff --git a/app/src/main/res/layout/activity_offline_map.xml b/app/src/main/res/layout/activity_offline_map.xml
index 245e410..86e941a 100644
--- a/app/src/main/res/layout/activity_offline_map.xml
+++ b/app/src/main/res/layout/activity_offline_map.xml
@@ -1,13 +1,37 @@
 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:orientation="vertical">
 
-    <com.google.android.material.tabs.TabLayout
-        android:id="@+id/sliding_tabs"
+    <RelativeLayout
         android:layout_width="match_parent"
-        android:layout_height="wrap_content"/>
+        android:layout_height="wrap_content"
+        android:background="@color/cadetblue"
+        android:theme="@style/Theme.AppCompat.Light.DarkActionBar">
+
+        <com.google.android.material.tabs.TabLayout
+            android:id="@+id/sliding_tabs"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            app:tabTextAppearance="@style/TabLayout.Bar.Txt"/>
+
+        <ImageButton
+            android:id="@+id/back"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_alignParentStart="true"
+            android:layout_alignParentTop="true"
+            android:layout_marginStart="14dp"
+            android:layout_marginTop="14dp"
+            android:onClick="goHome"
+            android:background="?android:attr/selectableItemBackgroundBorderless"
+            android:contentDescription="@string/map_home"
+            android:src="@drawable/ic_back"
+            android:theme="@style/RippleWhite" />
+
+    </RelativeLayout>
 
     <androidx.viewpager.widget.ViewPager
         android:id="@+id/viewpager"
diff --git a/app/src/main/res/values/styles.xml b/app/src/main/res/values/styles.xml
index 1178332..549717a 100644
--- a/app/src/main/res/values/styles.xml
+++ b/app/src/main/res/values/styles.xml
@@ -25,4 +25,15 @@
         <item name="android:radius">14dp</item>
     </style>
 
+    <!-- 修改tablayout的背景色，提示线的颜色，字体颜色等-->
+    <style name="TabLayout.Bar" parent="AppTheme">
+        <item name="tabBackground">@color/cadetblue</item>
+        <item name="tabTextAppearance">@style/TabLayout.Bar.Txt</item>
+        <item name="tabSelectedTextColor">#3D87FB</item>
+    </style>
+
+    <style name="TabLayout.Bar.Txt" parent="TextAppearance.AppCompat.Widget.ActionBar.Title">
+        <item name="android:textSize">15sp</item>
+        <item name="android:textColor">@color/white</item>
+    </style>
 </resources>