diff --git a/app/build.gradle b/app/build.gradle
index 5f10d213..7abfe87a 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -21,13 +21,12 @@ plugins {
 }
 
 android {
-    compileSdkVersion 30
-    buildToolsVersion "30.0.2"
+    compileSdk 33
 
     defaultConfig {
         applicationId "com.example.wordsapp"
-        minSdkVersion 19
-        targetSdkVersion 30
+        minSdk 21
+        targetSdk 33
         versionCode 1
         versionName "1.0"
 
@@ -50,7 +49,7 @@ android {
     }
 
     buildFeatures {
-        viewBinding = true
+        viewBinding true
     }
 }
 
diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index c484b611..5d46f3eb 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -15,6 +15,7 @@
      limitations under the License.
 -->
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
     package="com.example.wordsapp">
 
     <application
@@ -23,8 +24,11 @@
         android:label="@string/app_name"
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
-        android:theme="@style/Theme.Words">
-        <activity android:name=".MainActivity">
+        android:theme="@style/Theme.Words"
+        tools:ignore="AllowBackup">
+        <activity
+            android:name=".MainActivity"
+            android:exported="true">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
 
diff --git a/app/src/main/java/com/example/wordsapp/LetterAdapter.kt b/app/src/main/java/com/example/wordsapp/LetterAdapter.kt
index 0e42aea6..e27dda53 100644
--- a/app/src/main/java/com/example/wordsapp/LetterAdapter.kt
+++ b/app/src/main/java/com/example/wordsapp/LetterAdapter.kt
@@ -15,13 +15,11 @@
  */
 package com.example.wordsapp
 
-import android.os.Build
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import android.view.accessibility.AccessibilityNodeInfo
 import android.widget.Button
-import androidx.annotation.RequiresApi
 import androidx.navigation.findNavController
 import androidx.recyclerview.widget.RecyclerView
 
@@ -38,7 +36,7 @@ class LetterAdapter :
      * Provides a reference for the views needed to display items in your list.
      */
     class LetterViewHolder(val view: View) : RecyclerView.ViewHolder(view) {
-        val button = view.findViewById<Button>(R.id.button_item)
+        val button: Button = view.findViewById(R.id.button_item)
     }
 
     override fun getItemCount(): Int {
@@ -62,7 +60,7 @@ class LetterAdapter :
      * Replaces the content of an existing view with new data
      */
     override fun onBindViewHolder(holder: LetterViewHolder, position: Int) {
-        val item = list.get(position)
+        val item = list[position]
         holder.button.text = item.toString()
 
         // Assigns a [OnClickListener] to the button contained in the [ViewHolder]
@@ -78,23 +76,19 @@ class LetterAdapter :
     // Setup custom accessibility delegate to set the text read with
     // an accessibility service
     companion object Accessibility : View.AccessibilityDelegate() {
-        @RequiresApi(Build.VERSION_CODES.LOLLIPOP)
-        override fun onInitializeAccessibilityNodeInfo(
-            host: View?,
-            info: AccessibilityNodeInfo?
-        ) {
+        override fun onInitializeAccessibilityNodeInfo(host: View, info: AccessibilityNodeInfo) {
             super.onInitializeAccessibilityNodeInfo(host, info)
             // With `null` as the second argument to [AccessibilityAction], the
             // accessibility service announces "double tap to activate".
             // If a custom string is provided,
             // it announces "double tap to <custom string>".
-            val customString = host?.context?.getString(R.string.look_up_words)
+            val customString = host.context?.getString(R.string.look_up_words)
             val customClick =
                 AccessibilityNodeInfo.AccessibilityAction(
                     AccessibilityNodeInfo.ACTION_CLICK,
                     customString
                 )
-            info?.addAction(customClick)
+            info.addAction(customClick)
         }
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/example/wordsapp/LetterListFragment.kt b/app/src/main/java/com/example/wordsapp/LetterListFragment.kt
index 7a5c7aca..06fed8ba 100644
--- a/app/src/main/java/com/example/wordsapp/LetterListFragment.kt
+++ b/app/src/main/java/com/example/wordsapp/LetterListFragment.kt
@@ -16,12 +16,7 @@
 package com.example.wordsapp
 
 import android.os.Bundle
-import android.view.LayoutInflater
-import android.view.Menu
-import android.view.MenuInflater
-import android.view.MenuItem
-import android.view.View
-import android.view.ViewGroup
+import android.view.*
 import androidx.core.content.ContextCompat
 import androidx.fragment.app.Fragment
 import androidx.recyclerview.widget.GridLayoutManager
@@ -52,11 +47,10 @@ class LetterListFragment : Fragment() {
         inflater: LayoutInflater,
         container: ViewGroup?,
         savedInstanceState: Bundle?
-    ): View? {
+    ): View {
         // Retrieve and inflate the layout for this fragment
         _binding = FragmentLetterListBinding.inflate(inflater, container, false)
-        val view = binding.root
-        return view
+        return binding.root
     }
 
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
diff --git a/app/src/main/java/com/example/wordsapp/WordAdapter.kt b/app/src/main/java/com/example/wordsapp/WordAdapter.kt
index 53624b16..c401d0fc 100644
--- a/app/src/main/java/com/example/wordsapp/WordAdapter.kt
+++ b/app/src/main/java/com/example/wordsapp/WordAdapter.kt
@@ -18,17 +18,15 @@ package com.example.wordsapp
 import android.content.Context
 import android.content.Intent
 import android.net.Uri
-import android.os.Build
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import android.view.accessibility.AccessibilityNodeInfo
 import android.widget.Button
-import androidx.annotation.RequiresApi
 import androidx.recyclerview.widget.RecyclerView
 
 /**
- * Adapter for the [RecyclerView] in [DetailActivity].
+ * Adapter for the [RecyclerView] in [WordListFragment].
  */
 class WordAdapter(private val letterId: String, context: Context) :
     RecyclerView.Adapter<WordAdapter.WordViewHolder>() {
@@ -53,7 +51,7 @@ class WordAdapter(private val letterId: String, context: Context) :
     }
 
     class WordViewHolder(val view: View) : RecyclerView.ViewHolder(view) {
-        val button = view.findViewById<Button>(R.id.button_item)
+        val button: Button = view.findViewById(R.id.button_item)
     }
 
     override fun getItemCount(): Int = filteredWords.size
@@ -95,23 +93,19 @@ class WordAdapter(private val letterId: String, context: Context) :
     // Setup custom accessibility delegate to set the text read with
     // an accessibility service
     companion object Accessibility : View.AccessibilityDelegate() {
-        @RequiresApi(Build.VERSION_CODES.LOLLIPOP)
-        override fun onInitializeAccessibilityNodeInfo(
-            host: View?,
-            info: AccessibilityNodeInfo?
-        ) {
+        override fun onInitializeAccessibilityNodeInfo(host: View, info: AccessibilityNodeInfo) {
             super.onInitializeAccessibilityNodeInfo(host, info)
             // With `null` as the second argument to [AccessibilityAction], the
             // accessibility service announces "double tap to activate".
             // If a custom string is provided,
             // it announces "double tap to <custom string>".
-            val customString = host?.context?.getString(R.string.look_up_word)
+            val customString = host.context?.getString(R.string.look_up_word)
             val customClick =
                 AccessibilityNodeInfo.AccessibilityAction(
                     AccessibilityNodeInfo.ACTION_CLICK,
                     customString
                 )
-            info?.addAction(customClick)
+            info.addAction(customClick)
         }
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/example/wordsapp/WordListFragment.kt b/app/src/main/java/com/example/wordsapp/WordListFragment.kt
index 63252680..8127c598 100644
--- a/app/src/main/java/com/example/wordsapp/WordListFragment.kt
+++ b/app/src/main/java/com/example/wordsapp/WordListFragment.kt
@@ -22,6 +22,7 @@ import android.view.ViewGroup
 import androidx.fragment.app.Fragment
 import androidx.recyclerview.widget.DividerItemDecoration
 import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
 import com.example.wordsapp.databinding.FragmentWordListBinding
 
 /**
@@ -35,8 +36,8 @@ class WordListFragment : Fragment() {
      * a DetailListFragment instance.
      */
     companion object {
-        val LETTER = "letter"
-        val SEARCH_PREFIX = "https://www.google.com/search?q="
+        const val LETTER = "letter"
+        const val SEARCH_PREFIX = "https://www.google.com/search?q="
     }
 
     private var _binding: FragmentWordListBinding? = null
@@ -45,6 +46,7 @@ class WordListFragment : Fragment() {
     // onDestroyView.
     private val binding get() = _binding!!
 
+    private lateinit var recyclerView: RecyclerView
     private lateinit var letterId: String
 
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -60,14 +62,14 @@ class WordListFragment : Fragment() {
         inflater: LayoutInflater,
         container: ViewGroup?,
         savedInstanceState: Bundle?
-    ): View? {
+    ): View {
         // Retrieve and inflate the layout for this fragment
         _binding = FragmentWordListBinding.inflate(inflater, container, false)
         return binding.root
     }
 
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
-        val recyclerView = binding.recyclerView
+        recyclerView = binding.recyclerView
         recyclerView.layoutManager = LinearLayoutManager(requireContext())
         recyclerView.adapter = WordAdapter(letterId, requireContext())
 
diff --git a/app/src/main/res/layout/fragment_letter_list.xml b/app/src/main/res/layout/fragment_letter_list.xml
index 36d832ca..0992d080 100644
--- a/app/src/main/res/layout/fragment_letter_list.xml
+++ b/app/src/main/res/layout/fragment_letter_list.xml
@@ -1,5 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!--
+<?xml version="1.0" encoding="utf-8"?><!--
      Copyright (C) 2020 The Android Open Source Project
 
      Licensed under the Apache License, Version 2.0 (the "License");
diff --git a/app/src/main/res/navigation/nav_graph.xml b/app/src/main/res/navigation/nav_graph.xml
index 05119939..d5daea1f 100644
--- a/app/src/main/res/navigation/nav_graph.xml
+++ b/app/src/main/res/navigation/nav_graph.xml
@@ -17,7 +17,6 @@
 <navigation xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     xmlns:tools="http://schemas.android.com/tools"
-    android:id="@+id/nav_graph"
     app:startDestination="@id/letterListFragment">
 
     <fragment
diff --git a/app/src/main/res/values-night/themes.xml b/app/src/main/res/values-night/themes.xml
index eec467b5..053a78bd 100644
--- a/app/src/main/res/values-night/themes.xml
+++ b/app/src/main/res/values-night/themes.xml
@@ -25,6 +25,8 @@
         <item name="colorSecondary">@color/blue_200</item>
         <item name="colorSecondaryVariant">@color/blue_700</item>
         <item name="colorOnSecondary">@color/black</item>
+        <!-- Status bar color. -->
+        <item name="android:statusBarColor" tools:targetApi="l">?attr/colorPrimaryVariant</item>
         <!-- Customize your theme here. -->
     </style>
 </resources>
diff --git a/app/src/main/res/values/colors.xml b/app/src/main/res/values/colors.xml
index d3576b67..ac255222 100644
--- a/app/src/main/res/values/colors.xml
+++ b/app/src/main/res/values/colors.xml
@@ -21,7 +21,6 @@
 
     <color name="blue_200">#62A3FF</color>
     <color name="blue_700">#1675D1</color>
-    <color name="blue_900">#004A9F</color>
 
     <color name="black">#FF000000</color>
     <color name="white">#FFFFFFFF</color>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 7d69ddf9..9d1dba82 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -16,7 +16,6 @@
 -->
 <resources>
     <string name="app_name">Words</string>
-    <string name="detail_prefix">Words That Start With</string>
     <string name="action_switch_layout">Switch Layout</string>
     <string name="look_up_word">Look up word in a Browser Search</string>
     <string name="look_up_words">Show Stored Words</string>
diff --git a/app/src/main/res/values/styles.xml b/app/src/main/res/values/styles.xml
deleted file mode 100644
index c52a12d2..00000000
--- a/app/src/main/res/values/styles.xml
+++ /dev/null
@@ -1,21 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!--
-     Copyright (C) 2020 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.Words.TextView" parent="Widget.MaterialComponents.TextView">
-        <item name="android:textAppearance">?attr/textAppearanceHeadline4</item>
-    </style>
-</resources>
\ No newline at end of file
diff --git a/build.gradle b/build.gradle
index 89192bfc..f21793e0 100644
--- a/build.gradle
+++ b/build.gradle
@@ -16,21 +16,21 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 buildscript {
     ext {
-        appcompat_version = "1.2.0"
-        constraintlayout_version = "2.0.2"
-        core_ktx_version = "1.3.2"
-        kotlin_version = "1.5.30"
-        material_version = "1.2.1"
-        nav_version = "2.3.1"
+        appcompat_version = "1.4.2"
+        constraintlayout_version = "2.1.4"
+        core_ktx_version = "1.8.0"
+        kotlin_version = "1.7.10"
+        material_version = "1.6.1"
+        nav_version = '2.5.1'
         lifecycle_version = "2.3.1"
         datastore_version = "1.0.0"
     }
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:7.0.2'
+        classpath 'com.android.tools.build:gradle:7.2.2'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
         classpath "androidx.navigation:navigation-safe-args-gradle-plugin:$nav_version"
 
@@ -42,7 +42,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index f513a988..38987e91 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.0.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.3.3-bin.zip