diff --git a/app/build.gradle b/app/build.gradle
index 0a4704e0e..4185b5041 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -8,8 +8,8 @@ buildscript {
   }
 
   dependencies {
-    classpath 'com.android.tools.build:gradle:3.1.0'
-    classpath 'com.testdroid:gradle:1.5.0'
+    classpath "com.android.tools.build:gradle:$androidGradlePluginVersion"
+    classpath "com.testdroid:gradle:$testdroidGradlePluginVersion"
     classpath 'org.apache.httpcomponents:httpclient-android:4.3.3'
   }
 }
@@ -48,27 +48,27 @@ dependencies {
   implementation "com.android.support:support-v4:$supportLibraryVersion"
   implementation "com.android.support:design:$supportLibraryVersion"
   implementation "com.android.support:cardview-v7:$supportLibraryVersion"
-  implementation 'com.android.support:multidex:1.0.2'
+  implementation "com.android.support:multidex:$multidexVersion"
 
   implementation "com.android.support.constraint:constraint-layout:$constraintLayoutVersion"
 
   androidTestImplementation 'com.android.support.test.uiautomator:uiautomator-v18:2.1.3'
 
-  androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1', {
+  androidTestImplementation("com.android.support.test.espresso:espresso-core:$espressoVersion") {
     exclude group: 'com.android.support', module: 'support-annotations'
   }
 
-  androidTestImplementation 'com.android.support.test.espresso:espresso-web:3.0.1'
-  androidTestImplementation 'com.android.support.test.espresso:espresso-intents:3.0.1'
-  androidTestImplementation 'com.android.support.test.espresso:espresso-idling-resource:3.0.1'
-  androidTestImplementation 'com.android.support.test.espresso:espresso-contrib:3.0.0', {
+  androidTestImplementation "com.android.support.test.espresso:espresso-web:$espressoVersion"
+  androidTestImplementation "com.android.support.test.espresso:espresso-intents:$espressoVersion"
+  androidTestImplementation "com.android.support.test.espresso:espresso-idling-resource:$espressoVersion"
+  androidTestImplementation("com.android.support.test.espresso:espresso-contrib:$espressoVersion") {
     exclude group: 'com.android.support', module: 'support-v4'
     exclude group: 'com.android.support', module: 'appcompat-v7'
     exclude group: 'com.android.support', module: 'design'
     exclude group: 'com.android.support', module: 'recyclerview-v7'
   }
 
-  androidTestCompile('com.schibsted.spain:barista:2.4.0') {
+  androidTestImplementation('com.schibsted.spain:barista:2.4.0') {
     exclude group: 'com.android.support'
   }
 
@@ -97,7 +97,7 @@ dependencies {
   annotationProcessor 'com.yahoo.squidb:squidb-processor:2.0.0'
 
   // Apache
-  implementation 'commons-io:commons-io:2.5'
+  androidTestImplementation "commons-io:commons-io:$apacheCommonsVersion"
 
   // Square
   implementation "com.squareup.okhttp3:okhttp:$okHttpVersion"
@@ -111,9 +111,9 @@ dependencies {
   }
   androidTestImplementation 'com.squareup.okhttp3:mockwebserver:3.6.0'
 
-  // Butterknife
-  implementation 'com.jakewharton:butterknife:8.0.1'
-  annotationProcessor 'com.jakewharton:butterknife-compiler:8.0.1'
+  // ButterKnife
+  implementation "com.jakewharton:butterknife:$butterKnifeVersion"
+  annotationProcessor "com.jakewharton:butterknife-compiler:$butterKnifeVersion"
 
   // RxJava
   implementation "io.reactivex.rxjava2:rxandroid:$rxAndroidVersion"
@@ -156,7 +156,7 @@ if (project.hasProperty('customDir')) {
 }
 
 // Set up flavours for each custom app in the directory
-if(custom.listFiles()) {
+if (custom.listFiles()) {
   custom.eachFile() { file ->
 
     def fileName = file.getName()
@@ -285,15 +285,15 @@ android {
           sourceFile = file(directory + "/" + parsedJson.zim_file)
         }
         if (parsedJson.embed_zim) {
-         // Place content in each lib directory for embeded zims
+          // Place content in each lib directory for embeded zims
           for (String archName : archs) {
-           copy {
-             from sourceFile
-             into file(directory + "/jniLibs/" + archName)
-             rename { String filename -> "libcontent.so" }
-           }
-         }
-         parsedJson.zim_file = "libcontent.so"
+            copy {
+              from sourceFile
+              into file(directory + "/jniLibs/" + archName)
+              rename { String filename -> "libcontent.so" }
+            }
+          }
+          parsedJson.zim_file = "libcontent.so"
         }
         // Set custom config from json
         applicationId "$parsedJson.package"
@@ -329,7 +329,7 @@ android {
           buildConfigField "int", "CONTENT_VERSION_CODE", "$content_version_code"
         } else if (parsedJson.content_version_code != null) {
           buildConfigField "int", "CONTENT_VERSION_CODE", "$parsedJson.content_version_code"
-        } else if (project.hasProperty('version_code'))  {
+        } else if (project.hasProperty('version_code')) {
           def version_code = project.property('version_code')
           buildConfigField "int", "CONTENT_VERSION_CODE", "$version_code"
         } else if (parsedJson.version_code != null) {
diff --git a/app/src/main/res/layout/main.xml b/app/src/main/res/layout/main.xml
index 2827d47f1..099cdce66 100644
--- a/app/src/main/res/layout/main.xml
+++ b/app/src/main/res/layout/main.xml
@@ -109,6 +109,7 @@
         android:layout_alignParentBottom="true"
         android:layout_centerHorizontal="true"
         android:visibility="gone"
+        app:cardCornerRadius="0dp"
         app:cardElevation="8dp"
         tools:visibility="visible">
 
@@ -118,53 +119,68 @@
           android:background="@color/primary">
 
           <ImageView
-            android:id="@+id/bottom_toolbar_arrow_back"
-            android:layout_width="24dp"
-            android:layout_height="24dp"
+            android:id="@+id/bottom_toolbar_bookmark"
+            android:layout_width="0dp"
+            android:layout_height="0dp"
+            android:contentDescription="@string/menu_bookmarks"
+            android:paddingBottom="12dp"
+            android:paddingTop="12dp"
             app:layout_constraintBottom_toBottomOf="parent"
-            app:layout_constraintEnd_toStartOf="@id/bottom_toolbar_arrow_forward"
+            app:layout_constraintEnd_toStartOf="@id/bottom_toolbar_arrow_back"
             app:layout_constraintHorizontal_chainStyle="spread"
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toTopOf="parent"
-            app:srcCompat="@drawable/ic_keyboard_arrow_left_24dp" />
-
-          <ImageView
-            android:id="@+id/bottom_toolbar_arrow_forward"
-            android:layout_width="24dp"
-            android:layout_height="24dp"
-            app:layout_constraintBottom_toBottomOf="parent"
-            app:layout_constraintEnd_toStartOf="@id/bottom_toolbar_home"
-            app:layout_constraintStart_toEndOf="@id/bottom_toolbar_arrow_back"
-            app:layout_constraintTop_toTopOf="parent"
-            app:srcCompat="@drawable/ic_keyboard_arrow_right_24dp" />
-
-          <ImageView
-            android:id="@+id/bottom_toolbar_home"
-            android:layout_width="24dp"
-            android:layout_height="24dp"
-            app:layout_constraintBottom_toBottomOf="parent"
-            app:layout_constraintEnd_toStartOf="@id/bottom_toolbar_bookmark"
-            app:layout_constraintStart_toEndOf="@id/bottom_toolbar_arrow_forward"
-            app:layout_constraintTop_toTopOf="parent"
-            app:srcCompat="@drawable/action_home" />
-
-          <ImageView
-            android:id="@+id/bottom_toolbar_bookmark"
-            android:layout_width="24dp"
-            android:layout_height="24dp"
-            app:layout_constraintBottom_toBottomOf="parent"
-            app:layout_constraintEnd_toStartOf="@id/bottom_toolbar_toc"
-            app:layout_constraintStart_toEndOf="@id/bottom_toolbar_home"
-            app:layout_constraintTop_toTopOf="parent"
             app:srcCompat="@drawable/ic_bookmark_border_24dp" />
 
+          <ImageView
+            android:id="@+id/bottom_toolbar_arrow_back"
+            android:layout_width="0dp"
+            android:layout_height="0dp"
+            android:contentDescription="@string/go_to_previous_page"
+            android:paddingBottom="12dp"
+            android:paddingTop="12dp"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintEnd_toStartOf="@id/bottom_toolbar_home"
+            app:layout_constraintStart_toEndOf="@id/bottom_toolbar_bookmark"
+            app:layout_constraintTop_toTopOf="parent"
+            app:srcCompat="@drawable/ic_keyboard_arrow_left_24dp" />
+
+          <ImageView
+            android:id="@+id/bottom_toolbar_home"
+            android:layout_width="0dp"
+            android:layout_height="0dp"
+            android:contentDescription="@string/menu_home"
+            android:paddingBottom="12dp"
+            android:paddingTop="12dp"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintEnd_toStartOf="@id/bottom_toolbar_arrow_forward"
+            app:layout_constraintStart_toEndOf="@id/bottom_toolbar_arrow_back"
+            app:layout_constraintTop_toTopOf="parent"
+            app:srcCompat="@drawable/action_home" />
+
+          <ImageView
+            android:id="@+id/bottom_toolbar_arrow_forward"
+            android:layout_width="0dp"
+            android:layout_height="0dp"
+            android:contentDescription="@string/go_to_next_page"
+            android:paddingBottom="12dp"
+            android:paddingTop="12dp"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintEnd_toStartOf="@id/bottom_toolbar_toc"
+            app:layout_constraintStart_toEndOf="@id/bottom_toolbar_home"
+            app:layout_constraintTop_toTopOf="parent"
+            app:srcCompat="@drawable/ic_keyboard_arrow_right_24dp" />
+
           <ImageView
             android:id="@+id/bottom_toolbar_toc"
-            android:layout_width="24dp"
-            android:layout_height="24dp"
+            android:layout_width="0dp"
+            android:layout_height="0dp"
+            android:contentDescription="@string/table_of_contents"
+            android:paddingBottom="12dp"
+            android:paddingTop="12dp"
             app:layout_constraintBottom_toBottomOf="parent"
             app:layout_constraintEnd_toEndOf="parent"
-            app:layout_constraintStart_toEndOf="@id/bottom_toolbar_bookmark"
+            app:layout_constraintStart_toEndOf="@id/bottom_toolbar_arrow_forward"
             app:layout_constraintTop_toTopOf="parent"
             app:srcCompat="@drawable/ic_toc_24dp" />
         </android.support.constraint.ConstraintLayout>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 34c8a112c..7144c26bb 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -198,4 +198,7 @@
   <string name="save_books_offline">Save books offline</string>
   <string name="download_books_message">Download books and read wherever you are.</string>
   <string name="unable_to_add_to_bookmarks">Unable to add to bookmarks</string>
+  <string name="go_to_previous_page">Go to previous page</string>
+  <string name="go_to_next_page">Go to next page</string>
+  <string name="table_of_contents">Table of contents</string>
 </resources>
diff --git a/build.gradle b/build.gradle
index 297478dd6..22a3e46d4 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,12 +1,10 @@
-
-
 buildscript {
   repositories {
     jcenter()
-      google()
+    google()
   }
   dependencies {
-      classpath 'com.android.tools.build:gradle:3.1.0'
+    classpath "com.android.tools.build:gradle:3.1.3"
 
     // NOTE: Do not place your application dependencies here; they belong
     // in the individual module build.gradle files
@@ -14,24 +12,30 @@ buildscript {
 }
 
 ext {
+  androidGradlePluginVersion = '3.1.3'
+  testdroidGradlePluginVersion = '2.49.1'
   supportLibraryVersion = '27.1.1'
-    rxJavaVersion = '2.1.9'
-    rxAndroidVersion = '2.0.2'
-    okHttpVersion = '3.9.1'
-    retrofitVersion = '2.3.0'
-    javaxAnnotationVersion = '1.3.2'
-    daggerVersion = '2.15'
+  rxJavaVersion = '2.1.9'
+  rxAndroidVersion = '2.0.2'
+  okHttpVersion = '3.9.1'
+  retrofitVersion = '2.3.0'
+  javaxAnnotationVersion = '1.3.2'
+  daggerVersion = '2.16'
   inkPageIndicatorVersion = '1.3.0'
   constraintLayoutVersion = '1.1.0'
+  butterKnifeVersion = '8.8.1'
+  espressoVersion = '3.0.2'
+  apacheCommonsVersion = '2.6'
+  multidexVersion = '1.0.3'
 }
 
 allprojects {
-    repositories {
-        jcenter()
-        google()
-    }
+  repositories {
+    jcenter()
+    google()
+  }
 }
 
 task clean(type: Delete) {
-    delete rootProject.buildDir
+  delete rootProject.buildDir
 }