feat(android): add dark mode support following system theme (#101)

Co-authored-by: factory-droid[bot] <138933559+factory-droid[bot]@users.noreply.github.com>

Author: justinmoon

android/app/src/main/java/com/pika/app/ui/theme/Color.kt

@@ -3,5 +3,7 @@ package com.pika.app.ui.theme
 import androidx.compose.ui.graphics.Color
 
 val PikaBlue = Color(0xFF2C6BED)
+val PikaBlueDark = Color(0xFF5A8DF5)
 val PikaBg = Color(0xFFF6F7FB)
+val PikaBgDark = Color(0xFF121212)
 

android/app/src/main/java/com/pika/app/ui/theme/Theme.kt

@@ -1,11 +1,10 @@
 package com.pika.app.ui.theme
 
-import androidx.compose.foundation.background
+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.graphics.Color
 
 private val LightColors =
@@ -15,10 +14,19 @@ private val LightColors =
         background = PikaBg,
     )
 
+private val DarkColors =
+    darkColorScheme(
+        primary = PikaBlueDark,
+        surface = Color(0xFF1E1E1E),
+        background = PikaBgDark,
+    )
+
 @Composable
 fun PikaTheme(content: @Composable () -> Unit) {
+    val colorScheme = if (isSystemInDarkTheme()) DarkColors else LightColors
+
     MaterialTheme(
-        colorScheme = LightColors,
+        colorScheme = colorScheme,
         typography = androidx.compose.material3.Typography(),
         content = content,
     )

android/app/src/main/res/values-night/themes.xml

@@ -0,0 +1,6 @@
+<resources xmlns:tools="http://schemas.android.com/tools">
+    <style name="Theme.Pika" parent="Theme.MaterialComponents.DayNight.NoActionBar">
+        <item name="android:statusBarColor" tools:targetApi="l">@android:color/transparent</item>
+        <item name="android:windowLightStatusBar" tools:targetApi="m">false</item>
+    </style>
+</resources>

android/app/src/main/res/values/themes.xml

@@ -1,5 +1,6 @@
 <resources xmlns:tools="http://schemas.android.com/tools">
     <style name="Theme.Pika" parent="Theme.MaterialComponents.DayNight.NoActionBar">
-        <item name="android:statusBarColor" tools:targetApi="l">#FFFFFFFF</item>
+        <item name="android:statusBarColor" tools:targetApi="l">@android:color/transparent</item>
+        <item name="android:windowLightStatusBar" tools:targetApi="m">true</item>
     </style>
 </resources>