Update Settings components for dark theme

This CL updates the colors and properties of various themes and
widgets to make them follow dark theme UI. Specifically, it changes
the color accent and uses true black for the background.

Test: manual inspection
Bug: 111397440
Change-Id: I15214a4c5d4864244af856312d2fc3e3a7e7ce36
diff --git a/res/values-night/styles.xml b/res/values-night/styles.xml
new file mode 100644
index 0000000..87159b8
--- /dev/null
+++ b/res/values-night/styles.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+     Copyright (C) 2018 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+
+<resources>
+
+<style name="Widget.ActionBar.Base" parent="@android:style/Widget.DeviceDefault.ActionBar.Solid">
+  <item name="android:background">?android:attr/colorPrimaryDark</item>
+</style>
+
+</resources>
\ No newline at end of file