title: Set Title style for PreferenceCategory in PreferenceFragmentCompat
body: <p>I want to set title style for my preference fragment screen V14.<br>
  This is what I want:<br>
  <a href="https://i.stack.imgur.com/xr0w6.png" rel="noreferrer"><img src="https://i.stack.imgur.com/xr0w6.png" alt="enter image description here"></a></p>
  
  <p>I have followed<br> 
  <a href="https://stackoverflow.com/questions/6297635/custom-preferencecategory-headings?rq=1">Custom PreferenceCategory Headings</a>
  <br>
  I did manage to get the same screen but with PreferenceFragment!!<br>
  How can I do it for PreferenceFragmentCompat V14??</p>
  
  <p><br>
  Here is my Code<br>
  <br>
  <strong>Style.xml</strong><br></p>
  
  <pre><code>&lt;style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar"&gt;
      &lt;!-- Customize your theme here. --&gt;
      &lt;item name="colorPrimary"&gt;@color/colorPrimary&lt;/item&gt;
      &lt;item name="colorPrimaryDark"&gt;@color/colorPrimaryDark&lt;/item&gt;
      &lt;item name="colorAccent"&gt;@color/colorAccent&lt;/item&gt;
      &lt;item name="android:listSeparatorTextViewStyle"&gt;@style/PreferenceStyle&lt;/item&gt;
      &lt;item name="preferenceTheme"&gt;@style/PreferenceThemeOverlay.v14.Material&lt;/item&gt;
  &lt;/style&gt;
  
  &lt;style name="PreferenceStyle" parent="@android:style/Widget.TextView"&gt;
      &lt;item name="android:textColor"&gt;@color/colorDialogPop&lt;/item&gt;
      &lt;item name="android:textStyle"&gt;bold&lt;/item&gt;
      &lt;item name="android:textSize"&gt;@dimen/text_medium&lt;/item&gt;
      &lt;item name="android:padding"&gt;@dimen/padding_large&lt;/item&gt;
      &lt;item name="android:layout_marginLeft"&gt;@dimen/margin_medium&lt;/item&gt;
      &lt;item name="android:background"&gt;@color/colorAccent&lt;/item&gt;
  &lt;/style&gt;
  </code></pre>
  
  <p><br>
  <strong>preference.xml</strong><br></p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"&gt;
  
  &lt;PreferenceCategory android:title="@string/heading_general"
      android:layout="@layout/settings_text"&gt;
  
      &lt;SwitchPreference
          android:padding="@dimen/padding_medium"
          android:title="@string/enable_push" /&gt;
  
      &lt;SwitchPreference
          android:padding="@dimen/padding_medium"
          android:title="@string/send_email" /&gt;
  
  &lt;/PreferenceCategory&gt;
  
  &lt;PreferenceCategory android:title="@string/heading_account"
      android:layout="@layout/settings_text"&gt;
  
      &lt;EditTextPreference
          android:padding="@dimen/padding_medium"
          android:title="@string/email" /&gt;
  
      &lt;EditTextPreference
          android:padding="@dimen/padding_medium"
          android:title="@string/name" /&gt;
  
  &lt;/PreferenceCategory&gt;
  &lt;/PreferenceScreen&gt;
  </code></pre>
  
  <p><strong>setting_text.xml</strong> for layout of title text<br></p>
  
  <pre><code>&lt;TextView xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:id="@android:id/title"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  style="@style/PreferenceStyle"
  &gt;
  
  &lt;/TextView&gt;
  </code></pre>
  
  <p>All I get is this:<br>
  <a href="https://i.stack.imgur.com/kQiJX.png" rel="noreferrer"><img src="https://i.stack.imgur.com/kQiJX.png" alt="enter image description here"></a>
  <br></p>