diff --git a/androidApp/src/main/AndroidManifest.xml b/androidApp/src/main/AndroidManifest.xml
index 26403a7..298cd22 100644
--- a/androidApp/src/main/AndroidManifest.xml
+++ b/androidApp/src/main/AndroidManifest.xml
@@ -7,7 +7,7 @@
         android:label="@string/app_name"
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
-        android:theme="@android:style/Theme.Material.Light.NoActionBar">
+        android:theme="@style/Theme.YaYa">
         <activity
             android:exported="true"
             android:name=".MainActivity">
diff --git a/androidApp/src/main/res/values-night/themes.xml b/androidApp/src/main/res/values-night/themes.xml
new file mode 100644
index 0000000..ab14fc2
--- /dev/null
+++ b/androidApp/src/main/res/values-night/themes.xml
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <style name="Theme.YaYa" parent="@android:style/Theme.Material.NoActionBar" />
+</resources>
diff --git a/androidApp/src/main/res/values/themes.xml b/androidApp/src/main/res/values/themes.xml
new file mode 100644
index 0000000..3832c72
--- /dev/null
+++ b/androidApp/src/main/res/values/themes.xml
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <style name="Theme.YaYa" parent="@android:style/Theme.Material.Light.NoActionBar" />
+</resources>
diff --git a/shared/src/commonMain/kotlin/plus/rua/project/App.kt b/shared/src/commonMain/kotlin/plus/rua/project/App.kt
index c5693f4..2d87d1a 100644
--- a/shared/src/commonMain/kotlin/plus/rua/project/App.kt
+++ b/shared/src/commonMain/kotlin/plus/rua/project/App.kt
@@ -1,18 +1,22 @@
 package plus.rua.project
 
+import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.darkColorScheme
+import androidx.compose.material3.lightColorScheme
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.tooling.preview.Preview
 import plus.rua.project.ui.CalendarMonthView
 
 /**
- * 应用入口 Composable，包裹 CalendarMonthView 并提供 MaterialTheme。
+ * 应用入口 Composable，根据系统主题切换明暗 ColorScheme 并包裹 CalendarMonthView。
  */
 @Composable
 @Preview(name = "Calendar App")
 fun App() {
-    MaterialTheme {
+    val colorScheme = if (isSystemInDarkTheme()) darkColorScheme() else lightColorScheme()
+    MaterialTheme(colorScheme = colorScheme) {
         CalendarMonthView(modifier = Modifier)
     }
 }