Control system bar color

Signed-off-by: Percy Wegmann <percy@tailscale.com>

android/build.gradle

@@ -1,6 +1,7 @@
 buildscript {
     ext.kotlin_version = "1.9.22"
     ext.kotlin_compose_version = "1.5.10"
+    ext.accompanist_version = "0.34.0"
 
     repositories {
         google()
@@ -88,7 +89,8 @@ dependencies {
     implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.7.0'
     implementation 'androidx.lifecycle:lifecycle-viewmodel-ktx:2.7.0'
     implementation 'androidx.activity:activity-compose:1.8.2'
-    implementation "com.google.accompanist:accompanist-permissions:0.34.0"
+    implementation "com.google.accompanist:accompanist-permissions:$accompanist_version"
+    implementation "com.google.accompanist:accompanist-systemuicontroller:$accompanist_version"
 
     // Navigation dependencies.
     def nav_version = "2.7.7"

android/src/main/java/com/tailscale/ipn/ui/theme/Theme.kt

@@ -17,8 +17,10 @@ import androidx.compose.material3.Typography
 import androidx.compose.material3.darkColorScheme
 import androidx.compose.material3.lightColorScheme
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.unit.sp
+import com.google.accompanist.systemuicontroller.rememberSystemUiController
 
 @Composable
 fun AppTheme(useDarkTheme: Boolean = isSystemInDarkTheme(), content: @Composable() () -> Unit) {
@@ -39,6 +41,13 @@ fun AppTheme(useDarkTheme: Boolean = isSystemInDarkTheme(), content: @Composable
           bodyMedium =
               MaterialTheme.typography.bodyMedium.copy(fontSize = 16.sp, lineHeight = 26.sp))
 
+  val systemUiController = rememberSystemUiController()
+
+  DisposableEffect(systemUiController, useDarkTheme) {
+    systemUiController.setSystemBarsColor(color = colors.surfaceContainer)
+    onDispose {}
+  }
+
   MaterialTheme(colorScheme = colors, typography = typography, content = content)
 }