diff --git a/packages/notus/lib/notus.dart b/packages/notus/lib/notus.dart
index d61bcee0d..2c0179e79 100644
--- a/packages/notus/lib/notus.dart
+++ b/packages/notus/lib/notus.dart
@@ -15,3 +15,4 @@ export 'src/heuristics.dart';
 export 'src/heuristics/delete_rules.dart';
 export 'src/heuristics/format_rules.dart';
 export 'src/heuristics/insert_rules.dart';
+export 'src/history.dart';
diff --git a/packages/notus/lib/src/document.dart b/packages/notus/lib/src/document.dart
index 442486897..ad26a56cf 100644
--- a/packages/notus/lib/src/document.dart
+++ b/packages/notus/lib/src/document.dart
@@ -4,6 +4,7 @@
 import 'dart:async';
 
 import 'package:quill_delta/quill_delta.dart';
+import 'package:notus/notus.dart';
 
 import 'document/attributes.dart';
 import 'document/block.dart';
@@ -40,12 +41,14 @@ class NotusDocument {
   /// Creates new empty Notus document.
   NotusDocument()
       : _heuristics = NotusHeuristics.fallback,
+        _history = NotusHistory(),
         _delta = Delta()..insert('\n') {
     _loadDocument(_delta);
   }
 
   NotusDocument.fromJson(List data)
       : _heuristics = NotusHeuristics.fallback,
+        _history = NotusHistory(),
         _delta = Delta.fromJson(data) {
     _loadDocument(_delta);
   }
@@ -53,12 +56,22 @@ class NotusDocument {
   NotusDocument.fromDelta(Delta delta)
       : assert(delta != null),
         _heuristics = NotusHeuristics.fallback,
+        _history = NotusHistory(),
         _delta = delta {
     _loadDocument(_delta);
   }
 
   final NotusHeuristics _heuristics;
 
+  NotusHistory _history;
+
+  set history(NotusHistory value) {
+    _history?.clear();
+    _history = value;
+  }
+
+  NotusHistory get history => _history;
+
   /// The root node of this document tree.
   RootNode get root => _root;
   final RootNode _root = RootNode();
@@ -92,6 +105,7 @@ class NotusDocument {
   /// Closes [changes] stream.
   void close() {
     _controller.close();
+    _history.clear();
   }
 
   /// Inserts [text] in this document at specified [index].
@@ -216,7 +230,7 @@ class NotusDocument {
   /// of this document.
   ///
   /// In case the [change] is invalid, behavior of this method is unspecified.
-  void compose(Delta change, ChangeSource source) {
+  void compose(Delta change, ChangeSource source, {bool history}) {
     _checkMutable();
     change.trim();
     assert(change.isNotEmpty);
@@ -241,7 +255,9 @@ class NotusDocument {
       throw StateError('Compose produced inconsistent results. '
           'This is likely due to a bug in the library. Tried to compose change $change from $source.');
     }
-    _controller.add(NotusChange(before, change, source));
+    final notusChange = NotusChange(before, change, source);
+    _controller.add(notusChange);
+    if (history != true) _history?.handleDocChange(notusChange);
   }
 
   //
@@ -293,4 +309,12 @@ class NotusDocument {
       _root.remove(node);
     }
   }
+
+  void undo() {
+    _history?.undo(this);
+  }
+
+  void redo() {
+    _history?.redo(this);
+  }
 }
diff --git a/packages/notus/lib/src/document/attributes.dart b/packages/notus/lib/src/document/attributes.dart
index f2f222075..103466470 100644
--- a/packages/notus/lib/src/document/attributes.dart
+++ b/packages/notus/lib/src/document/attributes.dart
@@ -56,17 +56,24 @@ abstract class NotusAttributeBuilder<T> implements NotusAttributeKey<T> {
 ///       document.format(0, 5, NotusAttribute.bold);
 ///       // Similarly for italic
 ///       document.format(0, 5, NotusAttribute.italic);
+///       // Similarly for underline
+///       document.format(0, 5, NotusAttribute.underline)
 ///       // Format first line as a heading (h1)
 ///       // Note that there is no need to specify character range of the whole
 ///       // line. Simply set index position to anywhere within the line and
 ///       // length to 0.
 ///       document.format(0, 0, NotusAttribute.h1);
+///       // Note that there is no need to specify character range of the whole
+///       // line. Simply set index position to anywhere within the line and
+///       // length to 0.
+///       document.format(0, 0, NotusAttribute.left);
 ///     }
 ///
 /// List of supported attributes:
 ///
 ///   * [NotusAttribute.bold]
 ///   * [NotusAttribute.italic]
+///   * [NotusAttribute.underline]
 ///   * [NotusAttribute.link]
 ///   * [NotusAttribute.heading]
 ///   * [NotusAttribute.block]
@@ -74,6 +81,7 @@ class NotusAttribute<T> implements NotusAttributeBuilder<T> {
   static final Map<String, NotusAttributeBuilder> _registry = {
     NotusAttribute.bold.key: NotusAttribute.bold,
     NotusAttribute.italic.key: NotusAttribute.italic,
+    NotusAttribute.underline.key: NotusAttribute.underline,
     NotusAttribute.link.key: NotusAttribute.link,
     NotusAttribute.heading.key: NotusAttribute.heading,
     NotusAttribute.block.key: NotusAttribute.block,
@@ -88,6 +96,9 @@ class NotusAttribute<T> implements NotusAttributeBuilder<T> {
   /// Italic style attribute.
   static const italic = _ItalicAttribute();
 
+  /// Underline style attribure.
+  static const underline = _UnderlineAttribute();
+
   /// Link style attribute.
   // ignore: const_eval_throws_exception
   static const link = LinkAttributeBuilder._();
@@ -120,6 +131,18 @@ class NotusAttribute<T> implements NotusAttributeBuilder<T> {
   /// Alias for [NotusAttribute.block.quote].
   static NotusAttribute<String> get bq => block.quote;
 
+  /// Alias for [NotusAttribute.block.alignLeft].
+  static NotusAttribute<String> get alignLeft => block.alignLeft;
+
+  /// Alias for [NotusAttribute.block.alignRight].
+  static NotusAttribute<String> get alignRight => block.alignRight;
+
+  /// Alias for [NotusAttribute.block.alignCenter].
+  static NotusAttribute<String> get alignCenter => block.alignCenter;
+
+  /// Alias for [NotusAttribute.block.alignJustify].
+  static NotusAttribute<String> get alignJustify => block.alignJustify;
+
   /// Alias for [NotusAttribute.block.code].
   static NotusAttribute<String> get code => block.code;
 
@@ -332,6 +355,11 @@ class _ItalicAttribute extends NotusAttribute<bool> {
   const _ItalicAttribute() : super._('i', NotusAttributeScope.inline, true);
 }
 
+/// Applies underline style to a text segment.
+class _UnderlineAttribute extends NotusAttribute<bool> {
+  const _UnderlineAttribute() : super._('u', NotusAttributeScope.inline, true);
+}
+
 /// Builder for link attribute values.
 ///
 /// There is no need to use this class directly, consider using
@@ -387,6 +415,22 @@ class BlockAttributeBuilder extends NotusAttributeBuilder<String> {
   /// Formats a block of lines as a quote.
   NotusAttribute<String> get quote =>
       NotusAttribute<String>._(key, scope, 'quote');
+
+  /// Formats a block of lines into align left.
+  NotusAttribute<String> get alignLeft =>
+      NotusAttribute<String>._(key, scope, 'alignLeft');
+
+  /// Formats a block of lines into align right.
+  NotusAttribute<String> get alignRight =>
+      NotusAttribute<String>._(key, scope, 'alignRight');
+
+  /// Formats a block of lines into align center.
+  NotusAttribute<String> get alignCenter =>
+      NotusAttribute<String>._(key, scope, 'alignCenter');
+
+  /// Formats a block of lines into align justify.
+  NotusAttribute<String> get alignJustify =>
+      NotusAttribute<String>._(key, scope, 'alignJustify');
 }
 
 class EmbedAttributeBuilder
@@ -399,6 +443,9 @@ class EmbedAttributeBuilder
 
   NotusAttribute<Map<String, dynamic>> image(String source) =>
       EmbedAttribute.image(source);
+  
+  NotusAttribute<Map<String, dynamic>> video(String source) =>
+      EmbedAttribute.video(source);
 
   @override
   NotusAttribute<Map<String, dynamic>> get unset => EmbedAttribute._(null);
@@ -409,13 +456,14 @@ class EmbedAttributeBuilder
 }
 
 /// Type of embedded content.
-enum EmbedType { horizontalRule, image }
+enum EmbedType { horizontalRule, image, video }
 
 class EmbedAttribute extends NotusAttribute<Map<String, dynamic>> {
   static const _kValueEquality = MapEquality<String, dynamic>();
   static const _kEmbed = 'embed';
   static const _kHorizontalRuleEmbed = 'hr';
   static const _kImageEmbed = 'image';
+  static const _KVideoEmbed = 'video';
 
   EmbedAttribute._(Map<String, dynamic> value)
       : super._(_kEmbed, NotusAttributeScope.inline, value);
@@ -426,10 +474,14 @@ class EmbedAttribute extends NotusAttribute<Map<String, dynamic>> {
   EmbedAttribute.image(String source)
       : this._(<String, dynamic>{'type': _kImageEmbed, 'source': source});
 
+  EmbedAttribute.video(String source)
+      : this._(<String, dynamic>{'type': _KVideoEmbed, 'source': source});
+
   /// Type of this embed.
   EmbedType get type {
     if (value['type'] == _kHorizontalRuleEmbed) return EmbedType.horizontalRule;
     if (value['type'] == _kImageEmbed) return EmbedType.image;
+    if (value['type'] == _KVideoEmbed) return EmbedType.video;
     assert(false, 'Unknown embed attribute value $value.');
     return null;
   }
diff --git a/packages/notus/lib/src/document/block.dart b/packages/notus/lib/src/document/block.dart
index 3dc561456..a2729482a 100644
--- a/packages/notus/lib/src/document/block.dart
+++ b/packages/notus/lib/src/document/block.dart
@@ -10,7 +10,7 @@ import 'node.dart';
 /// A block represents a group of adjacent [LineNode]s with the same block
 /// style.
 ///
-/// Block examples: lists, quotes, code snippets.
+/// Block examples: lists, quotes, code snippets, alignment.
 class BlockNode extends ContainerNode<LineNode>
     with StyledNodeMixin
     implements StyledNode {
diff --git a/packages/notus/lib/src/history.dart b/packages/notus/lib/src/history.dart
new file mode 100644
index 000000000..ef6abb12c
--- /dev/null
+++ b/packages/notus/lib/src/history.dart
@@ -0,0 +1,119 @@
+import 'package:notus/notus.dart';
+import 'package:notus/src/document.dart';
+import 'package:quill_delta/quill_delta.dart';
+
+///
+/// record users operation or api change(Collaborative editing)
+/// used for redo or undo function
+///
+class NotusHistory {
+  final NotusHistoryStack stack = NotusHistoryStack.empty();
+
+  /// used for disable redo or undo function
+  bool ignoreChange;
+
+  int lastRecorded;
+
+  ///Collaborative editing's conditions should be true
+  final bool userOnly;
+
+  ///max operation count for undo
+  final int maxStack;
+
+  ///record delay
+  final int interval;
+
+  NotusHistory(
+      {this.ignoreChange = false,
+      this.interval = 400,
+      this.maxStack = 100,
+      this.userOnly = false,
+      this.lastRecorded = 0});
+
+  void handleDocChange(NotusChange event) {
+    if (ignoreChange) return;
+    if (!userOnly || event.source == ChangeSource.local) {
+      record(event.change, event.before);
+    } else {
+      transform(event.change);
+    }
+  }
+
+  void clear() {
+    stack.clear();
+  }
+
+  void record(Delta change, Delta before) {
+    if (change.isEmpty) return;
+    stack.redo.clear();
+    Delta undoDelta = change.invert(before);
+    final timeStamp = DateTime.now().millisecondsSinceEpoch;
+
+    if (lastRecorded + interval > timeStamp && stack.undo.isNotEmpty) {
+      final lastDelta = stack.undo.removeLast();
+      undoDelta = undoDelta.compose(lastDelta);
+    } else {
+      lastRecorded = timeStamp;
+    }
+
+    if (undoDelta.isEmpty) return;
+    stack.undo.add(undoDelta);
+
+    if (stack.undo.length > maxStack) {
+      stack.undo.removeAt(0);
+    }
+  }
+
+  ///
+  ///It will override pre local undo delta,replaced by remote change
+  ///
+  void transform(Delta delta) {
+    transformStack(this.stack.undo, delta);
+    transformStack(this.stack.redo, delta);
+  }
+
+  void transformStack(List<Delta> stack, Delta delta) {
+    for (int i = stack.length - 1; i >= 0; i -= 1) {
+      final oldDelta = stack[i];
+      stack[i] = delta.transform(oldDelta, true);
+      delta = oldDelta.transform(delta, false);
+      if (stack[i].length == 0) {
+        stack.removeAt(i);
+      }
+    }
+  }
+
+  void _change(NotusDocument doc, List<Delta> source, List<Delta> dest) {
+    if (source.length == 0) return;
+    Delta delta = source.removeLast();
+    Delta base = doc.toDelta();
+    Delta inverseDelta = delta.invert(base);
+    dest.add(inverseDelta);
+    this.lastRecorded = 0;
+    this.ignoreChange = true;
+    doc.compose(delta, ChangeSource.local, history: true);
+    this.ignoreChange = false;
+  }
+
+  void undo(NotusDocument doc) {
+    _change(doc, stack.undo, stack.redo);
+  }
+
+  void redo(NotusDocument doc) {
+    _change(doc, stack.redo, stack.undo);
+  }
+}
+
+class NotusHistoryStack {
+  final List<Delta> undo;
+  final List<Delta> redo;
+
+  NotusHistoryStack.empty()
+      : undo = [],
+        redo = [];
+
+  void clear() {
+    undo.clear();
+    redo.clear();
+  }
+}
diff --git a/packages/notus/pubspec.yaml b/packages/notus/pubspec.yaml
index 98777765d..91b6747a0 100644
--- a/packages/notus/pubspec.yaml
+++ b/packages/notus/pubspec.yaml
@@ -5,7 +5,7 @@ author: Anatoly Pulyaevskiy <anatoly.pulyaevskiy@gmail.com>
 homepage: https://github.com/memspace/zefyr
 
 environment:
-  sdk: '>=2.2.0 <3.0.0'
+  sdk: ">=2.2.0 <3.0.0"
 
 dependencies:
   collection: ^1.14.6
diff --git a/packages/zefyr/example/android/gradle.properties b/packages/zefyr/example/android/gradle.properties
index 8bd86f680..7be3d8b46 100644
--- a/packages/zefyr/example/android/gradle.properties
+++ b/packages/zefyr/example/android/gradle.properties
@@ -1 +1,2 @@
 org.gradle.jvmargs=-Xmx1536M
+android.enableR8=true
diff --git a/packages/zefyr/example/lib/generated_plugin_registrant.dart b/packages/zefyr/example/lib/generated_plugin_registrant.dart
new file mode 100644
index 000000000..26bf2561c
--- /dev/null
+++ b/packages/zefyr/example/lib/generated_plugin_registrant.dart
@@ -0,0 +1,14 @@
+//
+// Generated file. Do not edit.
+//
+
+import 'package:flutter_web_plugins/flutter_web_plugins.dart';
+// ignore_for_file: lines_longer_than_80_chars
+
+import 'package:url_launcher_web/url_launcher_web.dart';
+
+// ignore: public_member_api_docs
+void registerPlugins(Registrar registrar) {
+  UrlLauncherPlugin.registerWith(registrar);
+  registrar.messenger; //registerMessageHandler();
+}
diff --git a/packages/zefyr/example/lib/src/form.dart b/packages/zefyr/example/lib/src/form.dart
index 1b7024773..39fa95333 100644
--- a/packages/zefyr/example/lib/src/form.dart
+++ b/packages/zefyr/example/lib/src/form.dart
@@ -32,7 +32,7 @@ class _FormEmbeddedScreenState extends State<FormEmbeddedScreen> {
     );
 
     final result = Scaffold(
-      resizeToAvoidBottomPadding: true,
+      resizeToAvoidBottomInset: true,
       appBar: AppBar(
         title: ZefyrLogo(),
         actions: [
diff --git a/packages/zefyr/example/lib/src/full_page.dart b/packages/zefyr/example/lib/src/full_page.dart
index 599f50f7e..948c310ed 100644
--- a/packages/zefyr/example/lib/src/full_page.dart
+++ b/packages/zefyr/example/lib/src/full_page.dart
@@ -10,6 +10,7 @@ import 'package:quill_delta/quill_delta.dart';
 import 'package:zefyr/zefyr.dart';
 
 import 'images.dart';
+import 'videos.dart';
 
 class ZefyrLogo extends StatelessWidget {
   @override
@@ -31,7 +32,7 @@ class FullPageEditorScreen extends StatefulWidget {
 }
 
 final doc =
-    r'[{"insert":"Zefyr"},{"insert":"\n","attributes":{"heading":1}},{"insert":"Soft and gentle rich text editing for Flutter applications.","attributes":{"i":true}},{"insert":"\n"},{"insert":"​","attributes":{"embed":{"type":"image","source":"asset://images/breeze.jpg"}}},{"insert":"\n"},{"insert":"Photo by Hiroyuki Takeda.","attributes":{"i":true}},{"insert":"\nZefyr is currently in "},{"insert":"early preview","attributes":{"b":true}},{"insert":". If you have a feature request or found a bug, please file it at the "},{"insert":"issue tracker","attributes":{"a":"https://github.com/memspace/zefyr/issues"}},{"insert":'
+    r'[{"insert":"Zefyr"},{"insert":"\n","attributes":{"heading":1}},{"insert":"Soft and gentle rich text editing for Flutter applications.","attributes":{"i":true}},{"insert":"\n"},{"insert":"​","attributes":{"embed":{"type":"image","source":"asset://images/breeze.jpg"}}},{"insert":"\n"},{"insert":"Photo by Hiroyuki Takeda.","attributes":{"i":true}},{"insert":"\n"},{"insert":"​","attributes":{"embed":{"type":"video","source":"asset://video/nature_videos_UCDQ_Stczw0.mp4"}}},{"insert":"\n"},{"insert":"\nZefyr is currently in "},{"insert":"early preview","attributes":{"b":true}},{"insert":". If you have a feature request or found a bug, please file it at the "},{"insert":"issue tracker","attributes":{"a":"https://github.com/memspace/zefyr/issues"}},{"insert":'
     r'".\nDocumentation"},{"insert":"\n","attributes":{"heading":3}},{"insert":"Quick Start","attributes":{"a":"https://github.com/memspace/zefyr/blob/master/doc/quick_start.md"}},{"insert":"\n","attributes":{"block":"ul"}},{"insert":"Data Format and Document Model","attributes":{"a":"https://github.com/memspace/zefyr/blob/master/doc/data_and_document.md"}},{"insert":"\n","attributes":{"block":"ul"}},{"insert":"Style Attributes","attributes":{"a":"https://github.com/memspace/zefyr/blob/master/doc/attr'
     r'ibutes.md"}},{"insert":"\n","attributes":{"block":"ul"}},{"insert":"Heuristic Rules","attributes":{"a":"https://github.com/memspace/zefyr/blob/master/doc/heuristics.md"}},{"insert":"\n","attributes":{"block":"ul"}},{"insert":"FAQ","attributes":{"a":"https://github.com/memspace/zefyr/blob/master/doc/faq.md"}},{"insert":"\n","attributes":{"block":"ul"}},{"insert":"Clean and modern look"},{"insert":"\n","attributes":{"heading":2}},{"insert":"Zefyr’s rich text editor is built with simplicity and fle'
     r'xibility in mind. It provides clean interface for distraction-free editing. Think Medium.com-like experience.\nMarkdown inspired semantics"},{"insert":"\n","attributes":{"heading":2}},{"insert":"Ever needed to have a heading line inside of a quote block, like this:\nI’m a Markdown heading"},{"insert":"\n","attributes":{"block":"quote","heading":3}},{"insert":"And I’m a regular paragraph"},{"insert":"\n","attributes":{"block":"quote"}},{"insert":"Code blocks"},{"insert":"\n","attributes":{"headin'
@@ -71,7 +72,7 @@ class _FullPageEditorScreenState extends State<FullPageEditorScreen> {
         ? IconButton(onPressed: _stopEditing, icon: Icon(Icons.save))
         : IconButton(onPressed: _startEditing, icon: Icon(Icons.edit));
     final result = Scaffold(
-      resizeToAvoidBottomPadding: true,
+      resizeToAvoidBottomInset: true,
       appBar: AppBar(
         title: ZefyrLogo(),
         actions: [
@@ -88,6 +89,7 @@ class _FullPageEditorScreenState extends State<FullPageEditorScreen> {
           focusNode: _focusNode,
           mode: _editing ? ZefyrMode.edit : ZefyrMode.select,
           imageDelegate: CustomImageDelegate(),
+          videoDelegate: CustomVideoDelegate(),
           keyboardAppearance: _darkTheme ? Brightness.dark : Brightness.light,
         ),
       ),
diff --git a/packages/zefyr/example/lib/src/videoPlayer.dart b/packages/zefyr/example/lib/src/videoPlayer.dart
new file mode 100644
index 000000000..103113734
--- /dev/null
+++ b/packages/zefyr/example/lib/src/videoPlayer.dart
@@ -0,0 +1,65 @@
+import 'package:flutter/material.dart';
+import 'package:video_player/video_player.dart';
+
+class VideoApp extends StatefulWidget {
+  final String video;
+  VideoApp({this.video});
+  @override
+  _VideoAppState createState() => _VideoAppState();
+}
+
+class _VideoAppState extends State<VideoApp> {
+  VideoPlayerController _controller;
+
+  @override
+  void initState() {
+    super.initState();
+
+    _controller = widget.video == null
+        ? VideoPlayerController.network(
+            'https://flutter.github.io/assets-for-api-docs/assets/videos/bee.mp4')
+        : VideoPlayerController.asset(widget.video)
+      ..initialize().then((_) {
+        // Ensure the first frame is shown after the video is initialized, even before the play button has been pressed.
+        setState(() {});
+      });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      height: 300,
+      child: InkWell(
+        onTap: () {
+          setState(() {
+            _controller.value.isPlaying
+                ? _controller.pause()
+                : _controller.play();
+          });
+        },
+        child: Stack(alignment: Alignment.center, children: [
+          Center(
+              child: _controller.value.initialized
+                  ? AspectRatio(
+                      aspectRatio: _controller.value.aspectRatio,
+                      child: VideoPlayer(_controller),
+                    )
+                  : CircularProgressIndicator()),
+          _controller.value.isPlaying || !_controller.value.initialized
+              ? SizedBox.shrink()
+              : Icon(
+                  Icons.play_arrow,
+                  size: 60,
+                  color: Colors.white,
+                )
+        ]),
+      ),
+    );
+  }
+
+  @override
+  void dispose() {
+    super.dispose();
+    _controller.dispose();
+  }
+}
diff --git a/packages/zefyr/example/lib/src/videos.dart b/packages/zefyr/example/lib/src/videos.dart
new file mode 100644
index 000000000..a15559fc8
--- /dev/null
+++ b/packages/zefyr/example/lib/src/videos.dart
@@ -0,0 +1,48 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:flutter/material.dart';
+import 'package:flutter/widgets.dart';
+import 'package:image_picker/image_picker.dart';
+import 'package:zefyr/zefyr.dart';
+
+import 'videoPlayer.dart';
+
+/// Custom image delegate used by this example to load image from application
+/// assets.
+class CustomVideoDelegate implements ZefyrVideoDelegate<ImageSource> {
+  @override
+  ImageSource get cameraSource => ImageSource.camera;
+
+  @override
+  ImageSource get gallerySource => ImageSource.gallery;
+
+  /*@override
+  DataSourceType get asset => DataSourceType.asset;
+
+  @override
+  DataSourceType get network => DataSourceType.network;
+
+  @override
+  DataSourceType get file => DataSourceType.file;*/
+
+  @override
+  Future<String> pickVideo(ImageSource source) async {
+    final picker = ImagePicker();
+    final file = await picker.getVideo(source: ImageSource.gallery);
+    if (file == null) return null;
+    return file.path.toString();
+  }
+
+  @override
+  Widget buildVideo(BuildContext context, String key) {
+    // We use custom "asset" scheme to distinguish asset images from other files.
+    if (key.startsWith('asset://')) {
+      final asset = key.replaceFirst('asset://', '');
+      return VideoApp(video: asset);
+    } else {
+      return VideoApp();
+    }
+  }
+}
diff --git a/packages/zefyr/example/lib/src/view.dart b/packages/zefyr/example/lib/src/view.dart
index 9a0bfcacc..56c9f8a76 100644
--- a/packages/zefyr/example/lib/src/view.dart
+++ b/packages/zefyr/example/lib/src/view.dart
@@ -4,6 +4,7 @@
 
 import 'dart:convert';
 
+import 'package:example/src/videos.dart';
 import 'package:flutter/material.dart';
 import 'package:quill_delta/quill_delta.dart';
 import 'package:zefyr/zefyr.dart';
@@ -17,7 +18,7 @@ class ViewScreen extends StatefulWidget {
 }
 
 final doc =
-    r'[{"insert":"Zefyr"},{"insert":"\n","attributes":{"heading":1}},{"insert":"Soft and gentle rich text editing for Flutter applications.","attributes":{"i":true}},{"insert":"\n"},{"insert":"​","attributes":{"embed":{"type":"image","source":"asset://images/breeze.jpg"}}},{"insert":"\n"},{"insert":"Photo by Hiroyuki Takeda.","attributes":{"i":true}},{"insert":"\nZefyr is currently in "},{"insert":"early preview","attributes":{"b":true}},{"insert":". If you have a feature request or found a bug, please file it at the "},{"insert":"issue tracker","attributes":{"a":"https://github.com/memspace/zefyr/issues"}},{"insert":'
+    r'[{"insert":"Zefyr"},{"insert":"\n","attributes":{"heading":1}},{"insert":"Soft and gentle rich text editing for Flutter applications.","attributes":{"i":true}},{"insert":"\n"},{"insert":"​","attributes":{"embed":{"type":"image","source":"asset://images/breeze.jpg"}}},{"insert":"\n"},{"insert":"Photo by Hiroyuki Takeda.","attributes":{"i":true}},{"insert":"\n"},{"insert":"​","attributes":{"embed":{"type":"video","source":"asset://video/nature_videos_UCDQ_Stczw0.mp4"}}},{"insert":"\n"},{"insert":"\nZefyr is currently in "},{"insert":"early preview","attributes":{"b":true}},{"insert":". If you have a feature request or found a bug, please file it at the "},{"insert":"issue tracker","attributes":{"a":"https://github.com/memspace/zefyr/issues"}},{"insert":'
     r'".\nDocumentation"},{"insert":"\n","attributes":{"heading":3}},{"insert":"Quick Start","attributes":{"a":"https://github.com/memspace/zefyr/blob/master/doc/quick_start.md"}},{"insert":"\n","attributes":{"block":"ul"}},{"insert":"Data Format and Document Model","attributes":{"a":"https://github.com/memspace/zefyr/blob/master/doc/data_and_document.md"}},{"insert":"\n","attributes":{"block":"ul"}},{"insert":"Style Attributes","attributes":{"a":"https://github.com/memspace/zefyr/blob/master/doc/attr'
     r'ibutes.md"}},{"insert":"\n","attributes":{"block":"ul"}},{"insert":"Heuristic Rules","attributes":{"a":"https://github.com/memspace/zefyr/blob/master/doc/heuristics.md"}},{"insert":"\n","attributes":{"block":"ul"}},{"insert":"FAQ","attributes":{"a":"https://github.com/memspace/zefyr/blob/master/doc/faq.md"}},{"insert":"\n","attributes":{"block":"ul"}},{"insert":"Clean and modern look"},{"insert":"\n","attributes":{"heading":2}},{"insert":"Zefyr’s rich text editor is built with simplicity and fle'
     r'xibility in mind. It provides clean interface for distraction-free editing. Think Medium.com-like experience.\nMarkdown inspired semantics"},{"insert":"\n","attributes":{"heading":2}},{"insert":"Ever needed to have a heading line inside of a quote block, like this:\nI’m a Markdown heading"},{"insert":"\n","attributes":{"block":"quote","heading":3}},{"insert":"And I’m a regular paragraph"},{"insert":"\n","attributes":{"block":"quote"}},{"insert":"Code blocks"},{"insert":"\n","attributes":{"headin'
@@ -33,7 +34,7 @@ class _ViewScreen extends State<ViewScreen> {
   @override
   Widget build(BuildContext context) {
     return Scaffold(
-      resizeToAvoidBottomPadding: true,
+      resizeToAvoidBottomInset: true,
       appBar: AppBar(title: ZefyrLogo()),
       body: ListView(
         children: <Widget>[
@@ -50,8 +51,9 @@ class _ViewScreen extends State<ViewScreen> {
             child: ZefyrView(
               document: doc,
               imageDelegate: CustomImageDelegate(),
+              videoDelegate: CustomVideoDelegate(),
             ),
-          )
+          ),
         ],
       ),
     );
diff --git a/packages/zefyr/example/pubspec.yaml b/packages/zefyr/example/pubspec.yaml
index e914eaea8..01ad113e4 100644
--- a/packages/zefyr/example/pubspec.yaml
+++ b/packages/zefyr/example/pubspec.yaml
@@ -9,6 +9,9 @@ description: A new Flutter project.
 # Read more about versioning at semver.org.
 version: 1.0.0+1
 
+environment:
+  sdk: ">=2.2.0 <3.0.0"
+
 dependencies:
   flutter:
     sdk: flutter
@@ -19,6 +22,7 @@ dependencies:
   image_picker: ^0.6.1
   zefyr:
     path: ../
+  video_player: ^1.0.1
 
 dependency_overrides:
   notus:
@@ -43,6 +47,7 @@ flutter:
   # To add assets to your application, add an assets section, like this:
   assets:
     - images/breeze.jpg
+    - video/nature_videos_UCDQ_Stczw0.mp4
 
   # An image asset can refer to one or more resolution-specific "variants", see
   # https://flutter.io/assets-and-images/#resolution-aware.
diff --git a/packages/zefyr/example/video/nature_videos_UCDQ_Stczw0.mp4 b/packages/zefyr/example/video/nature_videos_UCDQ_Stczw0.mp4
new file mode 100644
index 000000000..695cf5142
Binary files /dev/null and b/packages/zefyr/example/video/nature_videos_UCDQ_Stczw0.mp4 differ
diff --git a/packages/zefyr/lib/src/widgets/__theme.dart b/packages/zefyr/lib/src/widgets/__theme.dart
index 15c806bfb..02405292f 100644
--- a/packages/zefyr/lib/src/widgets/__theme.dart
+++ b/packages/zefyr/lib/src/widgets/__theme.dart
@@ -55,6 +55,7 @@ class ZefyrTheme extends InheritedWidget {
 class ZefyrThemeData {
   final TextStyle boldStyle;
   final TextStyle italicStyle;
+  final TextStyle underlineStyle;
   final TextStyle linkStyle;
   final StyleTheme paragraphTheme;
   final HeadingTheme headingTheme;
@@ -76,12 +77,14 @@ class ZefyrThemeData {
     const padding = EdgeInsets.symmetric(vertical: 8.0);
     final boldStyle = TextStyle(fontWeight: FontWeight.bold);
     final italicStyle = TextStyle(fontStyle: FontStyle.italic);
+    final underlineStyle = TextStyle(decoration: TextDecoration.underline);
     final linkStyle = TextStyle(
         color: themeData.accentColor, decoration: TextDecoration.underline);
 
     return ZefyrThemeData(
       boldStyle: boldStyle,
       italicStyle: italicStyle,
+      underlineStyle: underlineStyle,
       linkStyle: linkStyle,
       paragraphTheme: StyleTheme(textStyle: paragraphStyle, padding: padding),
       headingTheme: HeadingTheme.fallback(context),
@@ -96,6 +99,7 @@ class ZefyrThemeData {
   const ZefyrThemeData({
     this.boldStyle,
     this.italicStyle,
+    this.underlineStyle,
     this.linkStyle,
     this.paragraphTheme,
     this.headingTheme,
@@ -110,6 +114,7 @@ class ZefyrThemeData {
     TextStyle textStyle,
     TextStyle boldStyle,
     TextStyle italicStyle,
+    TextStyle underlineStyle,
     TextStyle linkStyle,
     StyleTheme paragraphTheme,
     HeadingTheme headingTheme,
@@ -122,6 +127,7 @@ class ZefyrThemeData {
     return ZefyrThemeData(
       boldStyle: boldStyle ?? this.boldStyle,
       italicStyle: italicStyle ?? this.italicStyle,
+      underlineStyle: underlineStyle ?? this.underlineStyle,
       linkStyle: linkStyle ?? this.linkStyle,
       paragraphTheme: paragraphTheme ?? this.paragraphTheme,
       headingTheme: headingTheme ?? this.headingTheme,
@@ -137,6 +143,7 @@ class ZefyrThemeData {
     return copyWith(
       boldStyle: other.boldStyle,
       italicStyle: other.italicStyle,
+      underlineStyle: other.underlineStyle,
       linkStyle: other.linkStyle,
       paragraphTheme: other.paragraphTheme,
       headingTheme: other.headingTheme,
@@ -215,11 +222,27 @@ class BlockTheme {
   /// Style theme for quotes.
   final StyleTheme quote;
 
+  /// Style theme for align left
+  final StyleTheme alignLeft;
+
+  /// Style theme for align right
+  final StyleTheme alignRight;
+
+  /// Style theme for align center
+  final StyleTheme alignCenter;
+
+  /// Style theme for align justify
+  final StyleTheme alignJustify;
+
   BlockTheme({
     @required this.bulletList,
     @required this.numberList,
     @required this.quote,
     @required this.code,
+    @required this.alignLeft,
+    @required this.alignRight,
+    @required this.alignCenter,
+    @required this.alignJustify,
   });
 
   /// Creates fallback theme for blocks.
@@ -244,6 +267,10 @@ class BlockTheme {
     return BlockTheme(
       bulletList: StyleTheme(padding: padding),
       numberList: StyleTheme(padding: padding),
+      alignLeft: StyleTheme(padding: padding),
+      alignRight: StyleTheme(padding: padding),
+      alignJustify: StyleTheme(padding: padding),
+      alignCenter: StyleTheme(padding: padding),
       quote: StyleTheme(
         textStyle: TextStyle(
           color: defaultTextStyle.style.color.withOpacity(0.6),
@@ -265,7 +292,7 @@ class BlockTheme {
 
 /// Theme for a specific attribute style.
 ///
-/// Used in [HeadingTheme] and [BlockTheme], as well as in
+/// Used in [HeadingTheme], [AlignTheme] and [BlockTheme], as well as in
 /// [ZefyrThemeData.paragraphTheme].
 class StyleTheme {
   /// Text style of this theme.
diff --git a/packages/zefyr/lib/src/widgets/align.dart b/packages/zefyr/lib/src/widgets/align.dart
new file mode 100644
index 000000000..3c917ac76
--- /dev/null
+++ b/packages/zefyr/lib/src/widgets/align.dart
@@ -0,0 +1,76 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'package:flutter/material.dart';
+import 'package:notus/notus.dart';
+
+import 'paragraph.dart';
+import 'theme.dart';
+
+/// Represents number lists and bullet lists in a Zefyr editor.
+class ZefyrAlign extends StatelessWidget {
+  const ZefyrAlign({Key key, @required this.node}) : super(key: key);
+
+  final BlockNode node;
+
+  TextAlign _getTextAlign() {
+    final blockStyle = node.style.get(NotusAttribute.block);
+    if (blockStyle == NotusAttribute.block.alignLeft) {
+      return TextAlign.left;
+    } else if (blockStyle == NotusAttribute.block.alignRight) {
+      return TextAlign.right;
+    } else if (blockStyle == NotusAttribute.block.alignCenter) {
+      return TextAlign.center;
+    } else if (blockStyle == NotusAttribute.block.alignJustify) {
+      return TextAlign.justify;
+    }
+    return TextAlign.start;
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = ZefyrTheme.of(context);
+    List<Widget> items = [];
+    for (var line in node.children) {
+      items.add(_buildLine(
+        line,
+        null,
+        theme.indentWidth,
+      ));
+    }
+
+    return Column(children: items);
+  }
+
+  Widget _buildLine(Node node, TextStyle blockStyle, double indentSize) {
+    LineNode line = node;
+    final textAlign = _getTextAlign();
+    Widget content;
+
+    if (line.style.contains(NotusAttribute.heading)) {
+      content = ZefyrHeading(
+        node: line,
+        blockStyle: blockStyle,
+        textAlign: textAlign,
+      );
+    } else {
+      content = ZefyrParagraph(
+        node: line,
+        blockStyle: blockStyle,
+        textAlign: textAlign,
+      );
+    }
+
+    /// Uniquekey is needed because if the user switches from one alignment to another
+    /// it won't change immediately, since the change in alignment is change in style
+    /// flutter won't reflect it automatically, so generate a unique key each time.
+    return Row(
+      key: ValueKey(textAlign),
+      children: <Widget>[
+        Expanded(
+          child: content,
+        ),
+      ],
+    );
+  }
+}
diff --git a/packages/zefyr/lib/src/widgets/buttons.dart b/packages/zefyr/lib/src/widgets/buttons.dart
index 6f7ab2c7f..2a74bc052 100644
--- a/packages/zefyr/lib/src/widgets/buttons.dart
+++ b/packages/zefyr/lib/src/widgets/buttons.dart
@@ -110,11 +110,16 @@ class ZefyrButton extends StatelessWidget {
       return onPressed;
     } else if (isAttributeAction) {
       final attribute = kZefyrToolbarAttributeActions[action];
+
       if (attribute is NotusAttribute) {
         return () => _toggleAttribute(attribute, editor);
       }
     } else if (action == ZefyrToolbarAction.close) {
       return () => toolbar.closeOverlay();
+    } else if (action == ZefyrToolbarAction.undo) {
+      return () => editor.undo();
+    } else if (action == ZefyrToolbarAction.redo) {
+      return () => editor.redo();
     } else if (action == ZefyrToolbarAction.hideKeyboard) {
       return () => editor.hideKeyboard();
     }
@@ -124,6 +129,7 @@ class ZefyrButton extends StatelessWidget {
 
   void _toggleAttribute(NotusAttribute attribute, ZefyrScope editor) {
     final isToggled = editor.selectionStyle.containsSame(attribute);
+
     if (isToggled) {
       editor.formatSelection(attribute.unset);
     } else {
@@ -235,10 +241,208 @@ class _HeadingButtonState extends State<HeadingButton> {
   }
 }
 
-/// Controls image attribute.
+/// Controls align styles.
 ///
-/// When pressed, this button displays overlay toolbar with three
-/// buttons for each heading level.
+/// When pressed, this button displays overlay toolbar with four
+/// buttons for each align style.
+class AlignButton extends StatefulWidget {
+  const AlignButton({Key key}) : super(key: key);
+
+  @override
+  _AlignButtonState createState() => _AlignButtonState();
+}
+
+class _AlignButtonState extends State<AlignButton> {
+  @override
+  Widget build(BuildContext context) {
+    final toolbar = ZefyrToolbar.of(context);
+    return toolbar.buildButton(
+      context,
+      ZefyrToolbarAction.align,
+      onPressed: showOverlay,
+    );
+  }
+
+  void showOverlay() {
+    final toolbar = ZefyrToolbar.of(context);
+    toolbar.showOverlay(buildOverlay);
+  }
+
+  Widget buildOverlay(BuildContext context) {
+    final toolbar = ZefyrToolbar.of(context);
+    final buttons = Row(
+      children: <Widget>[
+        SizedBox(width: 8.0),
+        toolbar.buildButton(context, ZefyrToolbarAction.alignLeft),
+        toolbar.buildButton(context, ZefyrToolbarAction.alignRight),
+        toolbar.buildButton(context, ZefyrToolbarAction.alignCenter),
+        toolbar.buildButton(context, ZefyrToolbarAction.alignJustify),
+      ],
+    );
+    return ZefyrToolbarScaffold(body: buttons);
+  }
+}
+
+/// Controls video attribute.
+class VideoButton extends StatefulWidget {
+  const VideoButton({Key key}) : super(key: key);
+
+  @override
+  _VideoButtonState createState() => _VideoButtonState();
+}
+
+class _VideoButtonState extends State<VideoButton> {
+  String youtubeVideo;
+  ValueNotifier<bool> isPaste = ValueNotifier(true);
+  TextEditingController textEditingController = TextEditingController();
+
+  void _pickFromCamera() async {
+    final editor = ZefyrToolbar.of(context).editor;
+    final video =
+        await editor.videoDelegate.pickVideo(editor.videoDelegate.cameraSource);
+    if (video != null) {
+      editor.formatSelection(NotusAttribute.embed.video(video));
+    }
+  }
+
+  void _pickFromGallery() async {
+    final editor = ZefyrToolbar.of(context).editor;
+    final video = await editor.videoDelegate
+        .pickVideo(editor.videoDelegate.gallerySource);
+    if (video != null) {
+      editor.formatSelection(NotusAttribute.embed.video(video));
+    }
+  }
+
+  //TODO alternate possible for translation use Icons.done & Icons.close for OK & Cancel
+  void _youtubeLink() async {
+    final editor = ZefyrToolbar.of(context).editor;
+    await showDialog(
+        context: context,
+        builder: (context) {
+          return Center(
+            child: Container(
+              height: 200, //MediaQuery.of(context).size.height * .2,
+              width: MediaQuery.of(context).size.width * 0.95,
+              //padding: EdgeInsets.all(20),
+              margin: MediaQuery.of(context).viewInsets,
+              child: Material(
+                child: Container(
+                  padding: EdgeInsets.all(20),
+                  child: ValueListenableBuilder<bool>(
+                      valueListenable: isPaste,
+                      builder: (context, currentState, child) {
+                        return Column(
+                          mainAxisAlignment: MainAxisAlignment.center,
+                          crossAxisAlignment: CrossAxisAlignment.center,
+                          children: [
+                            TextField(
+                              autofocus: true,
+                              controller: textEditingController,
+                              decoration: InputDecoration(
+                                  suffixIcon: isPaste.value
+                                      ? IconButton(
+                                          icon: Icon(
+                                            Icons.paste,
+                                            color:
+                                                Theme.of(context).primaryColor,
+                                          ),
+                                          onPressed: () async {
+                                            final data =
+                                                await Clipboard.getData(
+                                                    Clipboard.kTextPlain);
+                                            if (data.text.isNotEmpty) {
+                                              isPaste.value = !isPaste.value;
+                                              textEditingController.text =
+                                                  data.text;
+                                            }
+                                          },
+                                        )
+                                      : IconButton(
+                                          icon: Icon(
+                                            Icons.clear,
+                                            color: Colors.red,
+                                          ),
+                                          onPressed: () async {
+                                            isPaste.value = !isPaste.value;
+                                            textEditingController.text = '';
+                                          },
+                                        ),
+                                  hintText: 'Add a Youtube Link here'),
+                            ),
+                            SizedBox(height: 20),
+                            Row(
+                              mainAxisAlignment: MainAxisAlignment.spaceAround,
+                              children: [
+                                FlatButton(
+                                  color: Theme.of(context).primaryColor,
+                                  onPressed: () {
+                                    youtubeVideo = null;
+                                    Navigator.pop(context);
+                                  },
+                                  child: Text('Cancel',
+                                      style: TextStyle(color: Colors.white)),
+                                ),
+                                FlatButton(
+                                  color: Theme.of(context).primaryColor,
+                                  onPressed: () {
+                                    youtubeVideo = textEditingController.text;
+                                    Navigator.pop(context);
+                                  },
+                                  child: Text(
+                                    'OK',
+                                    style: TextStyle(color: Colors.white),
+                                  ),
+                                ),
+                              ],
+                            ),
+                          ],
+                        );
+                      }),
+                ),
+              ),
+            ),
+          );
+        });
+    final video = youtubeVideo;
+    if (video != null) {
+      editor.formatSelection(NotusAttribute.embed.video(video));
+    }
+  }
+
+  Widget buildOverlay(BuildContext context) {
+    final toolbar = ZefyrToolbar.of(context);
+    final buttons = Row(
+      children: <Widget>[
+        SizedBox(width: 8.0),
+        toolbar.buildButton(context, ZefyrToolbarAction.cameraImage,
+            onPressed: _pickFromCamera),
+        toolbar.buildButton(context, ZefyrToolbarAction.galleryImage,
+            onPressed: _pickFromGallery),
+        toolbar.buildButton(context, ZefyrToolbarAction.link,
+            onPressed: _youtubeLink)
+      ],
+    );
+    return ZefyrToolbarScaffold(body: buttons);
+  }
+
+  void showOverlay() {
+    final toolbar = ZefyrToolbar.of(context);
+    toolbar.showOverlay(buildOverlay);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final toolbar = ZefyrToolbar.of(context);
+    return toolbar.buildButton(
+      context,
+      ZefyrToolbarAction.video,
+      onPressed: showOverlay,
+    );
+  }
+}
+
+/// Controls image attribute.
 class ImageButton extends StatefulWidget {
   const ImageButton({Key key}) : super(key: key);
 
@@ -348,7 +552,7 @@ class _LinkButtonState extends State<LinkButton> {
     final toolbar = ZefyrToolbar.of(context);
     setState(() {
       _inputKey = UniqueKey();
-      _inputController.text = getLink('https://');
+      _inputController.text = getLink("");
       _inputController.addListener(_handleInputChange);
       toolbar.markNeedsRebuild();
     });
@@ -359,18 +563,10 @@ class _LinkButtonState extends State<LinkButton> {
     setState(() {
       var error = false;
       if (_inputController.text.isNotEmpty) {
-        try {
-          var uri = Uri.parse(_inputController.text);
-          if ((uri.isScheme('https') || uri.isScheme('http')) &&
-              uri.host.isNotEmpty) {
-            toolbar.editor.formatSelection(
-                NotusAttribute.link.fromString(_inputController.text));
-          } else {
-            error = true;
-          }
-        } on FormatException {
-          error = true;
-        }
+        toolbar.editor.formatSelection(
+            NotusAttribute.link.fromString(_inputController.text));
+      } else {
+        error = true;
       }
       if (error) {
         _formatError = error;
@@ -567,8 +763,7 @@ class _LinkView extends StatelessWidget {
               value,
               maxLines: 1,
               overflow: TextOverflow.ellipsis,
-              style: theme.textTheme.subtitle1
-                  .copyWith(color: toolbarTheme.disabledIconColor),
+              style: theme.textTheme.subtitle1.copyWith(color: Colors.white),
             ),
           )
         ],
diff --git a/packages/zefyr/lib/src/widgets/common.dart b/packages/zefyr/lib/src/widgets/common.dart
index 633f296e8..6b97e3715 100644
--- a/packages/zefyr/lib/src/widgets/common.dart
+++ b/packages/zefyr/lib/src/widgets/common.dart
@@ -6,6 +6,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';
 import 'package:notus/notus.dart';
+import 'package:zefyr/src/widgets/video.dart';
 
 import 'editable_box.dart';
 import 'horizontal_rule.dart';
@@ -16,8 +17,13 @@ import 'theme.dart';
 
 /// Represents single line of rich text document in Zefyr editor.
 class ZefyrLine extends StatefulWidget {
-  const ZefyrLine({Key key, @required this.node, this.style, this.padding})
-      : assert(node != null),
+  const ZefyrLine({
+    Key key,
+    @required this.node,
+    this.style,
+    this.padding,
+    this.textAlign,
+  })  : assert(node != null),
         super(key: key);
 
   /// Line in the document represented by this widget.
@@ -30,6 +36,9 @@ class ZefyrLine extends StatefulWidget {
   /// Padding to add around this paragraph.
   final EdgeInsets padding;
 
+  /// TextAlign to add around the block of lines
+  final TextAlign textAlign;
+
   @override
   _ZefyrLineState createState() => _ZefyrLineState();
 }
@@ -40,6 +49,7 @@ class _ZefyrLineState extends State<ZefyrLine> {
   @override
   Widget build(BuildContext context) {
     final scope = ZefyrScope.of(context);
+
     if (scope.isEditable) {
       ensureVisible(context, scope);
     }
@@ -53,6 +63,7 @@ class _ZefyrLineState extends State<ZefyrLine> {
       content = ZefyrRichText(
         node: widget.node,
         text: buildText(context),
+        textAlign: widget.textAlign ?? TextAlign.start,
       );
     }
 
@@ -101,14 +112,14 @@ class _ZefyrLineState extends State<ZefyrLine> {
   }
 
   void bringIntoView(BuildContext context) {
-    ScrollableState scrollable = Scrollable.of(context);
+    final scrollable = Scrollable.of(context);
     final object = context.findRenderObject();
     assert(object.attached);
-    final RenderAbstractViewport viewport = RenderAbstractViewport.of(object);
+    final viewport = RenderAbstractViewport.of(object);
     assert(viewport != null);
 
-    final double offset = scrollable.position.pixels;
-    double target = viewport.getOffsetToReveal(object, 0.0).offset;
+    final offset = scrollable.position.pixels;
+    var target = viewport.getOffsetToReveal(object, 0.0).offset;
     if (target - offset < 0.0) {
       scrollable.position.jumpTo(target);
       return;
@@ -121,7 +132,7 @@ class _ZefyrLineState extends State<ZefyrLine> {
 
   TextSpan buildText(BuildContext context) {
     final theme = ZefyrTheme.of(context);
-    final List<TextSpan> children = widget.node.children
+    final children = widget.node.children
         .map((node) => _segmentToTextSpan(node, theme))
         .toList(growable: false);
     return TextSpan(style: widget.style, children: children);
@@ -138,7 +149,7 @@ class _ZefyrLineState extends State<ZefyrLine> {
   }
 
   TextStyle _getTextStyle(NotusStyle style, ZefyrThemeData theme) {
-    TextStyle result = TextStyle();
+    var result = TextStyle();
     if (style.containsSame(NotusAttribute.bold)) {
       result = result.merge(theme.attributeTheme.bold);
     }
@@ -148,6 +159,9 @@ class _ZefyrLineState extends State<ZefyrLine> {
     if (style.contains(NotusAttribute.link)) {
       result = result.merge(theme.attributeTheme.link);
     }
+    if (style.contains(NotusAttribute.underline)) {
+      result = result.merge(theme.attributeTheme.underline);
+    }
     return result;
   }
 
@@ -159,6 +173,8 @@ class _ZefyrLineState extends State<ZefyrLine> {
       return ZefyrHorizontalRule(node: node);
     } else if (embed.type == EmbedType.image) {
       return ZefyrImage(node: node, delegate: scope.imageDelegate);
+    } else if (embed.type == EmbedType.video) {
+      return ZefyrVideo(node: node, delegate: scope.videoDelegate);
     } else {
       throw UnimplementedError('Unimplemented embed type ${embed.type}');
     }
diff --git a/packages/zefyr/lib/src/widgets/controller.dart b/packages/zefyr/lib/src/widgets/controller.dart
index e3152defd..8107bd515 100644
--- a/packages/zefyr/lib/src/widgets/controller.dart
+++ b/packages/zefyr/lib/src/widgets/controller.dart
@@ -168,7 +168,8 @@ class ZefyrController extends ChangeNotifier {
 
     if (length == 0 &&
         (attribute.key == NotusAttribute.bold.key ||
-            attribute.key == NotusAttribute.italic.key)) {
+            attribute.key == NotusAttribute.italic.key ||
+            attribute.key == NotusAttribute.underline.key)) {
       // Add the attribute to our toggledStyle. It will be used later upon insertion.
       _toggledStyles = toggledStyles.put(attribute);
     }
@@ -193,6 +194,16 @@ class ZefyrController extends ChangeNotifier {
     formatText(index, length, attribute);
   }
 
+  void undo() {
+    document.undo();
+    updateSelection(TextSelection.collapsed(offset: document.length));
+  }
+
+  void redo() {
+    document.redo();
+    updateSelection(TextSelection.collapsed(offset: document.length));
+  }
+
   /// Returns style of specified text range.
   ///
   /// If nothing is selected but we've toggled an attribute,
diff --git a/packages/zefyr/lib/src/widgets/editable_text.dart b/packages/zefyr/lib/src/widgets/editable_text.dart
index ff44cfcc6..9ee5d64b0 100644
--- a/packages/zefyr/lib/src/widgets/editable_text.dart
+++ b/packages/zefyr/lib/src/widgets/editable_text.dart
@@ -5,6 +5,7 @@ import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/widgets.dart';
 import 'package:notus/notus.dart';
+import 'package:zefyr/src/widgets/video.dart';
 
 import 'code.dart';
 import 'common.dart';
@@ -21,6 +22,7 @@ import 'render_context.dart';
 import 'scope.dart';
 import 'selection.dart';
 import 'theme.dart';
+import 'align.dart';
 
 /// Core widget responsible for editing Zefyr documents.
 ///
@@ -35,6 +37,7 @@ class ZefyrEditableText extends StatefulWidget {
     @required this.controller,
     @required this.focusNode,
     @required this.imageDelegate,
+    @required this.videoDelegate,
     this.selectionControls,
     this.autofocus = true,
     this.mode = ZefyrMode.edit,
@@ -53,6 +56,7 @@ class ZefyrEditableText extends StatefulWidget {
   /// Controls whether this editor has keyboard focus.
   final FocusNode focusNode;
   final ZefyrImageDelegate imageDelegate;
+  final ZefyrVideoDelegate videoDelegate;
 
   /// Whether this text field should focus itself if nothing else is already
   /// focused.
@@ -239,7 +243,9 @@ class _ZefyrEditableTextState extends State<ZefyrEditableText>
   Widget _defaultChildBuilder(BuildContext context, Node node) {
     if (node is LineNode) {
       if (node.hasEmbed) {
-        return ZefyrLine(node: node);
+        return ZefyrLine(
+          node: node,
+        );
       } else if (node.style.contains(NotusAttribute.heading)) {
         return ZefyrHeading(node: node);
       }
@@ -248,6 +254,7 @@ class _ZefyrEditableTextState extends State<ZefyrEditableText>
 
     final BlockNode block = node;
     final blockStyle = block.style.get(NotusAttribute.block);
+
     if (blockStyle == NotusAttribute.block.code) {
       return ZefyrCode(node: block);
     } else if (blockStyle == NotusAttribute.block.bulletList) {
@@ -256,8 +263,15 @@ class _ZefyrEditableTextState extends State<ZefyrEditableText>
       return ZefyrList(node: block);
     } else if (blockStyle == NotusAttribute.block.quote) {
       return ZefyrQuote(node: block);
+    } else if (blockStyle == NotusAttribute.block.alignLeft) {
+      return ZefyrAlign(node: block);
+    } else if (blockStyle == NotusAttribute.block.alignRight) {
+      return ZefyrAlign(node: block);
+    } else if (blockStyle == NotusAttribute.block.alignCenter) {
+      return ZefyrAlign(node: block);
+    } else if (blockStyle == NotusAttribute.block.alignJustify) {
+      return ZefyrAlign(node: block);
     }
-
     throw UnimplementedError('Block format $blockStyle.');
   }
 
diff --git a/packages/zefyr/lib/src/widgets/editor.dart b/packages/zefyr/lib/src/widgets/editor.dart
index a9b873e69..ceedaeafa 100644
--- a/packages/zefyr/lib/src/widgets/editor.dart
+++ b/packages/zefyr/lib/src/widgets/editor.dart
@@ -4,6 +4,7 @@
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/widgets.dart';
+import 'package:zefyr/src/widgets/video.dart';
 
 import 'controller.dart';
 import 'editable_text.dart';
@@ -25,6 +26,7 @@ class ZefyrEditor extends StatefulWidget {
     this.padding = const EdgeInsets.symmetric(horizontal: 16.0),
     this.toolbarDelegate,
     this.imageDelegate,
+    this.videoDelegate,
     this.selectionControls,
     this.physics,
     this.keyboardAppearance,
@@ -59,6 +61,8 @@ class ZefyrEditor extends StatefulWidget {
   /// This delegate is required if embedding images is allowed.
   final ZefyrImageDelegate imageDelegate;
 
+  final ZefyrVideoDelegate videoDelegate;
+
   /// Optional delegate for building the text selection handles and toolbar.
   ///
   /// If not provided then platform-specific implementation is used by default.
@@ -83,6 +87,7 @@ class ZefyrEditor extends StatefulWidget {
 
 class _ZefyrEditorState extends State<ZefyrEditor> {
   ZefyrImageDelegate _imageDelegate;
+  ZefyrVideoDelegate _videoDelegate;
   ZefyrScope _scope;
   ZefyrThemeData _themeData;
   GlobalKey<ZefyrToolbarState> _toolbarKey;
@@ -130,6 +135,7 @@ class _ZefyrEditorState extends State<ZefyrEditor> {
   void initState() {
     super.initState();
     _imageDelegate = widget.imageDelegate;
+    _videoDelegate = widget.videoDelegate;
   }
 
   @override
@@ -142,6 +148,11 @@ class _ZefyrEditorState extends State<ZefyrEditor> {
       _imageDelegate = widget.imageDelegate;
       _scope.imageDelegate = _imageDelegate;
     }
+
+    if (widget.videoDelegate != oldWidget.videoDelegate) {
+      _videoDelegate = widget.videoDelegate;
+      _scope.videoDelegate = _videoDelegate;
+    }
   }
 
   @override
@@ -157,6 +168,7 @@ class _ZefyrEditorState extends State<ZefyrEditor> {
       _scope = ZefyrScope.editable(
         mode: widget.mode,
         imageDelegate: _imageDelegate,
+        videoDelegate: _videoDelegate,
         controller: widget.controller,
         focusNode: widget.focusNode,
         focusScope: FocusScope.of(context),
@@ -194,6 +206,7 @@ class _ZefyrEditorState extends State<ZefyrEditor> {
       controller: _scope.controller,
       focusNode: _scope.focusNode,
       imageDelegate: _scope.imageDelegate,
+      videoDelegate: _scope.videoDelegate,
       selectionControls: widget.selectionControls,
       autofocus: widget.autofocus,
       mode: widget.mode,
diff --git a/packages/zefyr/lib/src/widgets/field.dart b/packages/zefyr/lib/src/widgets/field.dart
index cf05b6a09..69842c309 100644
--- a/packages/zefyr/lib/src/widgets/field.dart
+++ b/packages/zefyr/lib/src/widgets/field.dart
@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart';
+import 'package:zefyr/src/widgets/video.dart';
 
 import 'controller.dart';
 import 'editor.dart';
@@ -19,6 +20,7 @@ class ZefyrField extends StatefulWidget {
   final ZefyrMode mode;
   final ZefyrToolbarDelegate toolbarDelegate;
   final ZefyrImageDelegate imageDelegate;
+  final ZefyrVideoDelegate videoDelegate;
   final ScrollPhysics physics;
 
   /// The appearance of the keyboard.
@@ -38,6 +40,7 @@ class ZefyrField extends StatefulWidget {
     this.mode,
     this.toolbarDelegate,
     this.imageDelegate,
+    this.videoDelegate,
     this.physics,
     this.keyboardAppearance,
   }) : super(key: key);
@@ -58,6 +61,7 @@ class _ZefyrFieldState extends State<ZefyrField> {
       mode: _effectiveMode,
       toolbarDelegate: widget.toolbarDelegate,
       imageDelegate: widget.imageDelegate,
+      videoDelegate: widget.videoDelegate,
       physics: widget.physics,
       keyboardAppearance: widget.keyboardAppearance,
     );
diff --git a/packages/zefyr/lib/src/widgets/image.dart b/packages/zefyr/lib/src/widgets/image.dart
index 49477869d..99c9cfc28 100644
--- a/packages/zefyr/lib/src/widgets/image.dart
+++ b/packages/zefyr/lib/src/widgets/image.dart
@@ -220,7 +220,7 @@ class RenderEditableImage extends RenderBox
         minWidth: 0.0,
         maxWidth: width,
         minHeight: 0.0,
-        maxHeight: (width * 9 / 16).floorToDouble(),
+        maxHeight: double.infinity,
       );
       child.layout(childConstraints, parentUsesSize: true);
       _lastChildSize = child.size;
diff --git a/packages/zefyr/lib/src/widgets/input.dart b/packages/zefyr/lib/src/widgets/input.dart
index e40647b89..b0a310962 100644
--- a/packages/zefyr/lib/src/widgets/input.dart
+++ b/packages/zefyr/lib/src/widgets/input.dart
@@ -15,6 +15,19 @@ class InputConnectionController implements TextInputClient {
   //
   // public members
   //
+  //todo: fill this
+  @override
+  void showAutocorrectionPromptRect(int start, int end) {
+    throw UnimplementedError();
+  }
+
+  @override
+  dynamic noSuchMethod(Invocation i) => super.noSuchMethod(i);
+
+  @override
+  AutofillScope get currentAutofillScope {
+    throw UnimplementedError();
+  }
 
   final RemoteValueChanged onValueChanged;
 
diff --git a/packages/zefyr/lib/src/widgets/mode.dart b/packages/zefyr/lib/src/widgets/mode.dart
index b658c9f50..a7cb70b55 100644
--- a/packages/zefyr/lib/src/widgets/mode.dart
+++ b/packages/zefyr/lib/src/widgets/mode.dart
@@ -5,7 +5,7 @@ import 'package:quiver_hashcode/hashcode.dart';
 ///
 // TODO: consider extending with following:
 //       - linkTapBehavior: none|launch
-//       - allowedStyles: ['bold', 'italic', 'image', ... ]
+//       - allowedStyles: ['bold', 'italic', 'image', 'underline', ... ]
 class ZefyrMode {
   /// Editing mode provides full access to all editing features: keyboard,
   /// editor toolbar with formatting tools, selection controls and selection
diff --git a/packages/zefyr/lib/src/widgets/paragraph.dart b/packages/zefyr/lib/src/widgets/paragraph.dart
index f6b6c8947..9820f9d5d 100644
--- a/packages/zefyr/lib/src/widgets/paragraph.dart
+++ b/packages/zefyr/lib/src/widgets/paragraph.dart
@@ -9,47 +9,54 @@ import 'theme.dart';
 
 /// Represents regular paragraph line in a Zefyr editor.
 class ZefyrParagraph extends StatelessWidget {
-  ZefyrParagraph({Key key, @required this.node, this.blockStyle})
+  ZefyrParagraph(
+      {Key key, @required this.node, this.blockStyle, this.textAlign})
       : super(key: key);
 
   final LineNode node;
   final TextStyle blockStyle;
+  final TextAlign textAlign;
 
   @override
   Widget build(BuildContext context) {
     final theme = ZefyrTheme.of(context);
-    TextStyle style = theme.defaultLineTheme.textStyle;
+    var style = theme.defaultLineTheme.textStyle;
     if (blockStyle != null) {
       style = style.merge(blockStyle);
     }
+
     return ZefyrLine(
       node: node,
       style: style,
       padding: theme.defaultLineTheme.padding,
+      textAlign: textAlign,
     );
   }
 }
 
 /// Represents heading-styled line in [ZefyrEditor].
 class ZefyrHeading extends StatelessWidget {
-  ZefyrHeading({Key key, @required this.node, this.blockStyle})
+  ZefyrHeading({Key key, @required this.node, this.blockStyle, this.textAlign})
       : assert(node.style.contains(NotusAttribute.heading)),
         super(key: key);
 
   final LineNode node;
   final TextStyle blockStyle;
+  final TextAlign textAlign;
 
   @override
   Widget build(BuildContext context) {
     final theme = themeOf(node, context);
-    TextStyle style = theme.textStyle;
+    var style = theme.textStyle;
     if (blockStyle != null) {
       style = style.merge(blockStyle);
     }
+
     return ZefyrLine(
       node: node,
       style: style,
       padding: theme.padding,
+      textAlign: textAlign,
     );
   }
 
diff --git a/packages/zefyr/lib/src/widgets/quote.dart b/packages/zefyr/lib/src/widgets/quote.dart
index f6e3f720b..7f9a66b28 100644
--- a/packages/zefyr/lib/src/widgets/quote.dart
+++ b/packages/zefyr/lib/src/widgets/quote.dart
@@ -17,7 +17,7 @@ class ZefyrQuote extends StatelessWidget {
   Widget build(BuildContext context) {
     final theme = ZefyrTheme.of(context);
     final style = theme.attributeTheme.quote.textStyle;
-    List<Widget> items = [];
+    final List<Widget> items = [];
     for (var line in node.children) {
       items.add(_buildLine(line, style, theme.indentWidth));
     }
diff --git a/packages/zefyr/lib/src/widgets/rich_text.dart b/packages/zefyr/lib/src/widgets/rich_text.dart
index 6154a2d66..06f9e15e3 100644
--- a/packages/zefyr/lib/src/widgets/rich_text.dart
+++ b/packages/zefyr/lib/src/widgets/rich_text.dart
@@ -16,10 +16,12 @@ class ZefyrRichText extends LeafRenderObjectWidget {
   ZefyrRichText({
     @required this.node,
     @required this.text,
+    @required this.textAlign,
   }) : assert(node != null && text != null);
 
   final LineNode node;
   final TextSpan text;
+  final TextAlign textAlign;
 
   @override
   RenderObject createRenderObject(BuildContext context) {
@@ -27,6 +29,7 @@ class ZefyrRichText extends LeafRenderObjectWidget {
       text,
       node: node,
       textDirection: Directionality.of(context),
+      textAlign: textAlign,
     );
   }
 
@@ -44,7 +47,7 @@ class RenderZefyrParagraph extends RenderParagraph
   RenderZefyrParagraph(
     TextSpan text, {
     @required LineNode node,
-    TextAlign textAlign = TextAlign.start,
+    @required TextAlign textAlign,
     @required TextDirection textDirection,
     bool softWrap = true,
     TextOverflow overflow = TextOverflow.clip,
@@ -67,6 +70,7 @@ class RenderZefyrParagraph extends RenderParagraph
           maxLines: maxLines,
         );
 
+  @override
   LineNode node;
 
   @override
diff --git a/packages/zefyr/lib/src/widgets/scope.dart b/packages/zefyr/lib/src/widgets/scope.dart
index 9acfcc126..3cd9120f0 100644
--- a/packages/zefyr/lib/src/widgets/scope.dart
+++ b/packages/zefyr/lib/src/widgets/scope.dart
@@ -1,6 +1,7 @@
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:notus/notus.dart';
+import 'package:zefyr/src/widgets/video.dart';
 
 import 'controller.dart';
 import 'cursor_timer.dart';
@@ -25,10 +26,12 @@ class ZefyrScope extends ChangeNotifier {
   /// Creates a view-only scope.
   ///
   /// Normally used in [ZefyrView].
-  ZefyrScope.view({ZefyrImageDelegate imageDelegate})
+  ZefyrScope.view(
+      {ZefyrImageDelegate imageDelegate, ZefyrVideoDelegate videoDelegate})
       : isEditable = false,
         _mode = ZefyrMode.view,
-        _imageDelegate = imageDelegate;
+        _imageDelegate = imageDelegate,
+        _videoDelegate = videoDelegate;
 
   /// Creates editable scope.
   ///
@@ -39,6 +42,7 @@ class ZefyrScope extends ChangeNotifier {
     @required FocusNode focusNode,
     @required FocusScopeNode focusScope,
     ZefyrImageDelegate imageDelegate,
+    ZefyrVideoDelegate videoDelegate,
   })  : assert(mode != null),
         assert(controller != null),
         assert(focusNode != null),
@@ -47,6 +51,7 @@ class ZefyrScope extends ChangeNotifier {
         _mode = mode,
         _controller = controller,
         _imageDelegate = imageDelegate,
+        _videoDelegate = videoDelegate,
         _focusNode = focusNode,
         _focusScope = focusScope,
         _cursorTimer = CursorTimer(),
@@ -72,6 +77,15 @@ class ZefyrScope extends ChangeNotifier {
     }
   }
 
+  ZefyrVideoDelegate _videoDelegate;
+  ZefyrVideoDelegate get videoDelegate => _videoDelegate;
+  set videoDelegate(ZefyrVideoDelegate value) {
+    if (_videoDelegate != value) {
+      _videoDelegate = value;
+      notifyListeners();
+    }
+  }
+
   ZefyrMode _mode;
   ZefyrMode get mode => _mode;
   set mode(ZefyrMode value) {
@@ -181,6 +195,18 @@ class ZefyrScope extends ChangeNotifier {
     _controller.formatSelection(value);
   }
 
+  void undo() {
+    assert(isEditable);
+    assert(!_disposed);
+    _controller.undo();
+  }
+
+  void redo() {
+    assert(isEditable);
+    assert(!_disposed);
+    _controller.redo();
+  }
+
   void focus() {
     assert(isEditable);
     assert(!_disposed);
diff --git a/packages/zefyr/lib/src/widgets/selection.dart b/packages/zefyr/lib/src/widgets/selection.dart
index 081a2919f..19bc09cfd 100644
--- a/packages/zefyr/lib/src/widgets/selection.dart
+++ b/packages/zefyr/lib/src/widgets/selection.dart
@@ -102,7 +102,7 @@ class _ZefyrSelectionOverlayState extends State<ZefyrSelectionOverlay>
   }
 
   @override
-  void hideToolbar() {
+  void hideToolbar([bool hideHandles = true]) {
     _didCaretTap = false; // reset double tap.
     _toolbar?.remove();
     _toolbar = null;
@@ -273,8 +273,13 @@ class _ZefyrSelectionOverlayState extends State<ZefyrSelectionOverlay>
     _longPressPosition = null;
     HitTestResult result = HitTestResult();
     WidgetsBinding.instance.hitTest(result, globalPoint);
-    final box = _getEditableBox(result);
+    var box = _getEditableBox(result);
     if (box == null) {
+      if (isToolbarVisible) {
+        hideToolbar();
+      } else {
+        showToolbar();
+      }
       return;
     }
     final localPoint = box.globalToLocal(globalPoint);
@@ -284,6 +289,13 @@ class _ZefyrSelectionOverlayState extends State<ZefyrSelectionOverlay>
       baseOffset: word.start,
       extentOffset: word.end,
     );
+    if (selection.baseOffset == 0 && selection.extentOffset == 0) {
+      if (isToolbarVisible) {
+        hideToolbar();
+      } else {
+        showToolbar();
+      }
+    }
     _scope.controller.updateSelection(selection, source: ChangeSource.local);
   }
 
@@ -298,6 +310,12 @@ class _ZefyrSelectionOverlayState extends State<ZefyrSelectionOverlay>
 
   @override
   bool get selectAllEnabled => _scope.mode.canSelect;
+
+  @override
+  void userUpdateTextEditingValue(
+      TextEditingValue value, SelectionChangedCause cause) {
+    // TODO: implement userUpdateTextEditingValue
+  }
 }
 
 enum _SelectionHandlePosition { base, extent }
@@ -597,7 +615,8 @@ class _SelectionToolbarState extends State<_SelectionToolbar> {
         block.preferredLineHeight,
         midpoint,
         endpoints,
-        widget.selectionOverlay);
+        widget.selectionOverlay,
+        null);
     return CompositedTransformFollower(
       link: block.layerLink,
       showWhenUnlinked: false,
diff --git a/packages/zefyr/lib/src/widgets/theme.dart b/packages/zefyr/lib/src/widgets/theme.dart
index f90496e9e..2e12f1ee2 100644
--- a/packages/zefyr/lib/src/widgets/theme.dart
+++ b/packages/zefyr/lib/src/widgets/theme.dart
@@ -142,7 +142,7 @@ class ZefyrThemeData {
 
 /// Holds typography values for a document line in Zefyr editor.
 ///
-/// Applicable for regular paragraphs, headings and lines within blocks
+/// Applicable for regular paragraphs, headings, align and lines within blocks
 /// (lists, quotes). Blocks may override some of these values using [BlockTheme].
 @immutable
 class LineTheme {
@@ -291,6 +291,9 @@ class AttributeTheme {
   /// Style used to render text containing links.
   final TextStyle link;
 
+  // Style theme used to render underline blocks
+  final TextStyle underline;
+
   /// Style theme used to render largest headings.
   final LineTheme heading1;
 
@@ -309,6 +312,12 @@ class AttributeTheme {
   /// Style theme used to render quote blocks.
   final BlockTheme quote;
 
+  /// Style theme used to render align block.
+  final BlockTheme alignLeft;
+  final BlockTheme alignRight;
+  final BlockTheme alignCenter;
+  final BlockTheme alignJustify;
+
   /// Style theme used to render code blocks.
   final BlockTheme code;
 
@@ -316,6 +325,7 @@ class AttributeTheme {
   AttributeTheme({
     this.bold,
     this.italic,
+    this.underline,
     this.link,
     this.heading1,
     this.heading2,
@@ -324,6 +334,10 @@ class AttributeTheme {
     this.numberList,
     this.quote,
     this.code,
+    this.alignLeft,
+    this.alignCenter,
+    this.alignJustify,
+    this.alignRight,
   });
 
   /// The default attribute theme.
@@ -347,27 +361,28 @@ class AttributeTheme {
     return AttributeTheme(
       bold: TextStyle(fontWeight: FontWeight.bold),
       italic: TextStyle(fontStyle: FontStyle.italic),
+      underline: TextStyle(decoration: TextDecoration.underline),
       link: TextStyle(
         decoration: TextDecoration.underline,
         color: theme.accentColor,
       ),
       heading1: LineTheme(
         textStyle: defaultLineTheme.textStyle.copyWith(
-          fontSize: 34.0,
-          color: defaultLineTheme.textStyle.color.withOpacity(0.7),
+          fontSize: 24.0,
+          color: Colors.black,
           height: 1.15,
-          fontWeight: FontWeight.w300,
+          fontWeight: FontWeight.bold,
         ),
-        padding: EdgeInsets.only(top: 16.0),
+        padding: EdgeInsets.only(top: 5.0),
       ),
       heading2: LineTheme(
         textStyle: defaultLineTheme.textStyle.copyWith(
-          fontSize: 24.0,
-          color: defaultLineTheme.textStyle.color.withOpacity(0.7),
+          fontSize: 20.0,
+          color: Colors.black,
           height: 1.15,
-          fontWeight: FontWeight.normal,
+          fontWeight: FontWeight.bold,
         ),
-        padding: EdgeInsets.only(top: 8.0),
+        padding: EdgeInsets.only(top: 5.0),
       ),
       heading3: LineTheme(
         textStyle: defaultLineTheme.textStyle.copyWith(
@@ -393,6 +408,10 @@ class AttributeTheme {
         ),
         inheritLineTextStyle: true,
       ),
+      alignLeft: BlockTheme(),
+      alignRight: BlockTheme(),
+      alignCenter: BlockTheme(),
+      alignJustify: BlockTheme(),
       code: BlockTheme(
         padding: EdgeInsets.symmetric(vertical: 8.0),
         textStyle: TextStyle(
@@ -412,6 +431,7 @@ class AttributeTheme {
   AttributeTheme copyWith({
     TextStyle bold,
     TextStyle italic,
+    TextStyle underline,
     TextStyle link,
     LineTheme heading1,
     LineTheme heading2,
@@ -419,11 +439,16 @@ class AttributeTheme {
     BlockTheme bulletList,
     BlockTheme numberList,
     BlockTheme quote,
+    BlockTheme alignLeft,
+    BlockTheme alignRight,
+    BlockTheme alignJustify,
+    BlockTheme alignCenter,
     BlockTheme code,
   }) {
     return AttributeTheme(
       bold: bold ?? this.bold,
       italic: italic ?? this.italic,
+      underline: underline ?? this.underline,
       link: link ?? this.link,
       heading1: heading1 ?? this.heading1,
       heading2: heading2 ?? this.heading2,
@@ -431,6 +456,10 @@ class AttributeTheme {
       bulletList: bulletList ?? this.bulletList,
       numberList: numberList ?? this.numberList,
       quote: quote ?? this.quote,
+      alignLeft: alignLeft ?? this.alignLeft,
+      alignRight: alignRight ?? this.alignRight,
+      alignJustify: alignJustify ?? this.alignJustify,
+      alignCenter: alignCenter ?? this.alignCenter,
       code: code ?? this.code,
     );
   }
@@ -442,6 +471,7 @@ class AttributeTheme {
     return copyWith(
       bold: bold?.merge(other.bold) ?? other.bold,
       italic: italic?.merge(other.italic) ?? other.italic,
+      underline: underline?.merge(other.underline) ?? other.underline,
       link: link?.merge(other.link) ?? other.link,
       heading1: heading1?.merge(other.heading1) ?? other.heading1,
       heading2: heading2?.merge(other.heading2) ?? other.heading2,
@@ -449,6 +479,11 @@ class AttributeTheme {
       bulletList: bulletList?.merge(other.bulletList) ?? other.bulletList,
       numberList: numberList?.merge(other.numberList) ?? other.numberList,
       quote: quote?.merge(other.quote) ?? other.quote,
+      alignCenter: alignCenter?.merge(other.alignCenter) ?? other.alignCenter,
+      alignJustify:
+          alignJustify?.merge(other.alignJustify) ?? other.alignJustify,
+      alignRight: alignRight?.merge(other.alignRight) ?? other.alignRight,
+      alignLeft: alignLeft?.merge(other.alignLeft) ?? other.alignLeft,
       code: code?.merge(other.code) ?? other.code,
     );
   }
@@ -459,6 +494,7 @@ class AttributeTheme {
     final AttributeTheme otherTheme = other;
     return (otherTheme.bold == bold) &&
         (otherTheme.italic == italic) &&
+        (otherTheme.underline == underline) &&
         (otherTheme.link == link) &&
         (otherTheme.heading1 == heading1) &&
         (otherTheme.heading2 == heading2) &&
@@ -466,6 +502,10 @@ class AttributeTheme {
         (otherTheme.bulletList == bulletList) &&
         (otherTheme.numberList == numberList) &&
         (otherTheme.quote == quote) &&
+        (otherTheme.alignLeft == alignLeft) &&
+        (otherTheme.alignRight == alignRight) &&
+        (otherTheme.alignCenter == alignCenter) &&
+        (otherTheme.alignJustify == alignJustify) &&
         (otherTheme.code == code);
   }
 
@@ -474,6 +514,7 @@ class AttributeTheme {
     return hashList([
       bold,
       italic,
+      underline,
       link,
       heading1,
       heading2,
diff --git a/packages/zefyr/lib/src/widgets/toolbar.dart b/packages/zefyr/lib/src/widgets/toolbar.dart
index 72a610327..09cb7d557 100644
--- a/packages/zefyr/lib/src/widgets/toolbar.dart
+++ b/packages/zefyr/lib/src/widgets/toolbar.dart
@@ -15,6 +15,7 @@ import 'theme.dart';
 enum ZefyrToolbarAction {
   bold,
   italic,
+  underline,
   link,
   unlink,
   clipboardCopy,
@@ -23,6 +24,11 @@ enum ZefyrToolbarAction {
   headingLevel1,
   headingLevel2,
   headingLevel3,
+  align,
+  alignLeft,
+  alignRight,
+  alignCenter,
+  alignJustify,
   bulletList,
   numberList,
   code,
@@ -34,16 +40,24 @@ enum ZefyrToolbarAction {
   hideKeyboard,
   close,
   confirm,
+  undo,
+  redo,
+  video
 }
 
 final kZefyrToolbarAttributeActions = <ZefyrToolbarAction, NotusAttributeKey>{
   ZefyrToolbarAction.bold: NotusAttribute.bold,
   ZefyrToolbarAction.italic: NotusAttribute.italic,
+  ZefyrToolbarAction.underline: NotusAttribute.underline,
   ZefyrToolbarAction.link: NotusAttribute.link,
   ZefyrToolbarAction.heading: NotusAttribute.heading,
   ZefyrToolbarAction.headingLevel1: NotusAttribute.heading.level1,
   ZefyrToolbarAction.headingLevel2: NotusAttribute.heading.level2,
   ZefyrToolbarAction.headingLevel3: NotusAttribute.heading.level3,
+  ZefyrToolbarAction.alignLeft: NotusAttribute.block.alignLeft,
+  ZefyrToolbarAction.alignRight: NotusAttribute.block.alignRight,
+  ZefyrToolbarAction.alignCenter: NotusAttribute.block.alignCenter,
+  ZefyrToolbarAction.alignJustify: NotusAttribute.block.alignJustify,
   ZefyrToolbarAction.bulletList: NotusAttribute.block.bulletList,
   ZefyrToolbarAction.numberList: NotusAttribute.block.numberList,
   ZefyrToolbarAction.code: NotusAttribute.block.code,
@@ -252,14 +266,19 @@ class ZefyrToolbarState extends State<ZefyrToolbar>
     final buttons = <Widget>[
       buildButton(context, ZefyrToolbarAction.bold),
       buildButton(context, ZefyrToolbarAction.italic),
+      buildButton(context, ZefyrToolbarAction.underline),
+      if (editor.imageDelegate != null) ImageButton(),
+      if (editor.videoDelegate != null) VideoButton(),
       LinkButton(),
       HeadingButton(),
+      AlignButton(),
       buildButton(context, ZefyrToolbarAction.bulletList),
       buildButton(context, ZefyrToolbarAction.numberList),
       buildButton(context, ZefyrToolbarAction.quote),
       buildButton(context, ZefyrToolbarAction.code),
       buildButton(context, ZefyrToolbarAction.horizontalRule),
-      if (editor.imageDelegate != null) ImageButton(),
+      buildButton(context, ZefyrToolbarAction.undo),
+      buildButton(context, ZefyrToolbarAction.redo),
     ];
     return buttons;
   }
@@ -337,11 +356,17 @@ class _DefaultZefyrToolbarDelegate implements ZefyrToolbarDelegate {
   static const kDefaultButtonIcons = {
     ZefyrToolbarAction.bold: Icons.format_bold,
     ZefyrToolbarAction.italic: Icons.format_italic,
+    ZefyrToolbarAction.underline: Icons.format_underlined,
     ZefyrToolbarAction.link: Icons.link,
     ZefyrToolbarAction.unlink: Icons.link_off,
     ZefyrToolbarAction.clipboardCopy: Icons.content_copy,
     ZefyrToolbarAction.openInBrowser: Icons.open_in_new,
     ZefyrToolbarAction.heading: Icons.format_size,
+    ZefyrToolbarAction.alignLeft: Icons.format_align_left,
+    ZefyrToolbarAction.alignRight: Icons.format_align_right,
+    ZefyrToolbarAction.alignCenter: Icons.format_align_center,
+    ZefyrToolbarAction.alignJustify: Icons.format_align_justify,
+    ZefyrToolbarAction.align: Icons.format_align_center,
     ZefyrToolbarAction.bulletList: Icons.format_list_bulleted,
     ZefyrToolbarAction.numberList: Icons.format_list_numbered,
     ZefyrToolbarAction.code: Icons.code,
@@ -353,6 +378,9 @@ class _DefaultZefyrToolbarDelegate implements ZefyrToolbarDelegate {
     ZefyrToolbarAction.hideKeyboard: Icons.keyboard_hide,
     ZefyrToolbarAction.close: Icons.close,
     ZefyrToolbarAction.confirm: Icons.check,
+    ZefyrToolbarAction.undo: Icons.undo,
+    ZefyrToolbarAction.redo: Icons.redo,
+    ZefyrToolbarAction.video: Icons.movie,
   };
 
   static const kSpecialIconSizes = {
@@ -361,6 +389,8 @@ class _DefaultZefyrToolbarDelegate implements ZefyrToolbarDelegate {
     ZefyrToolbarAction.openInBrowser: 20.0,
     ZefyrToolbarAction.close: 20.0,
     ZefyrToolbarAction.confirm: 20.0,
+    ZefyrToolbarAction.undo: 20.0,
+    ZefyrToolbarAction.redo: 20.0,
   };
 
   static const kDefaultButtonTexts = {
diff --git a/packages/zefyr/lib/src/widgets/video.dart b/packages/zefyr/lib/src/widgets/video.dart
new file mode 100644
index 000000000..d47042723
--- /dev/null
+++ b/packages/zefyr/lib/src/widgets/video.dart
@@ -0,0 +1,231 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'dart:async';
+import 'dart:math' as math;
+import 'dart:ui' as ui;
+
+import 'package:flutter/rendering.dart';
+import 'package:flutter/widgets.dart';
+import 'package:meta/meta.dart';
+import 'package:notus/notus.dart';
+import 'package:zefyr/zefyr.dart';
+
+import 'editable_box.dart';
+
+/// Provides interface for embedding video into Zefyr editor.
+@experimental
+abstract class ZefyrVideoDelegate<S> {
+  /// Unique key to identify camera source.
+  S get cameraSource;
+
+  /// Unique key to identify gallery source.
+  S get gallerySource;
+
+  /// Builds video widget for specified video [key].
+  ///
+  /// The [key] argument contains value which was previously returned from
+  /// [pickVideo] method.
+  Widget buildVideo(BuildContext context, String key);
+
+  /// Picks an video from specified [source].
+  ///
+  /// Returns unique string key for the selected video. Returned key is stored
+  /// in the document.
+  ///
+  /// Depending on your application returned key may represent a path to
+  /// an video file on user's device, an HTTP link, or an identifier generated
+  /// by a file hosting service like AWS S3 or Google Drive.
+  Future<String> pickVideo(S source);
+}
+
+class ZefyrVideo extends StatefulWidget {
+  const ZefyrVideo({Key key, @required this.node, @required this.delegate})
+      : super(key: key);
+
+  final EmbedNode node;
+  final ZefyrVideoDelegate delegate;
+
+  @override
+  _ZefyrVideoState createState() => _ZefyrVideoState();
+}
+
+class _ZefyrVideoState extends State<ZefyrVideo> {
+  String get videoSource {
+    EmbedAttribute attribute = widget.node.style.get(NotusAttribute.embed);
+    return attribute.value['source'] as String;
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = ZefyrTheme.of(context);
+    final video = widget.delegate.buildVideo(context, videoSource);
+    return _EditableVideo(
+      child: Padding(
+        padding: theme.defaultLineTheme.padding,
+        child: video,
+      ),
+      node: widget.node,
+    );
+  }
+}
+
+class _EditableVideo extends SingleChildRenderObjectWidget {
+  _EditableVideo({@required Widget child, @required this.node})
+      : assert(node != null),
+        super(child: child);
+
+  final EmbedNode node;
+
+  @override
+  RenderEditableVideo createRenderObject(BuildContext context) {
+    return RenderEditableVideo(node: node);
+  }
+
+  @override
+  void updateRenderObject(
+      BuildContext context, RenderEditableVideo renderObject) {
+    renderObject..node = node;
+  }
+}
+
+class RenderEditableVideo extends RenderBox
+    with RenderObjectWithChildMixin<RenderBox>, RenderProxyBoxMixin<RenderBox>
+    implements RenderEditableBox {
+  RenderEditableVideo({
+    TextureBox child,
+    @required EmbedNode node,
+  }) : node = node {
+    this.child = child;
+  }
+
+  @override
+  EmbedNode node;
+
+  // TODO: Customize caret height offset instead of adjusting here by 2px.
+  @override
+  double get preferredLineHeight => size.height + 2.0;
+
+  @override
+  SelectionOrder get selectionOrder => SelectionOrder.foreground;
+
+  @override
+  TextSelection getLocalSelection(TextSelection documentSelection) {
+    if (!intersectsWithSelection(documentSelection)) return null;
+
+    int nodeBase = node.documentOffset;
+    int nodeExtent = nodeBase + node.length;
+    int base = math.max(0, documentSelection.baseOffset - nodeBase);
+    int extent =
+        math.min(documentSelection.extentOffset, nodeExtent) - nodeBase;
+    return documentSelection.copyWith(baseOffset: base, extentOffset: extent);
+  }
+
+  @override
+  List<ui.TextBox> getEndpointsForSelection(TextSelection selection) {
+    TextSelection local = getLocalSelection(selection);
+    if (local.isCollapsed) {
+      final dx = local.extentOffset == 0 ? _childOffset.dx : size.width;
+      return [
+        ui.TextBox.fromLTRBD(dx, 0.0, dx, size.height, TextDirection.ltr),
+      ];
+    }
+
+    final rect = _childRect;
+    return [
+      ui.TextBox.fromLTRBD(
+          rect.left, rect.top, rect.left, rect.bottom, TextDirection.ltr),
+      ui.TextBox.fromLTRBD(
+          rect.right, rect.top, rect.right, rect.bottom, TextDirection.ltr),
+    ];
+  }
+
+  @override
+  TextPosition getPositionForOffset(Offset offset) {
+    int position = node.documentOffset;
+
+    if (offset.dx > size.width / 2) {
+      position++;
+    }
+    return TextPosition(offset: position);
+  }
+
+  @override
+  TextRange getWordBoundary(TextPosition position) {
+    final start = node.documentOffset;
+    return TextRange(start: start, end: start + 1);
+  }
+
+  @override
+  bool intersectsWithSelection(TextSelection selection) {
+    final int base = node.documentOffset;
+    final int extent = base + node.length;
+    return base <= selection.extentOffset && selection.baseOffset <= extent;
+  }
+
+  @override
+  Offset getOffsetForCaret(TextPosition position, Rect caretPrototype) {
+    final pos = position.offset - node.documentOffset;
+    Offset caretOffset = _childOffset - Offset(kHorizontalPadding, 0.0);
+    if (pos == 1) {
+      caretOffset =
+          caretOffset + Offset(_lastChildSize.width + kHorizontalPadding, 0.0);
+    }
+    return caretOffset;
+  }
+
+  @override
+  void paintSelection(PaintingContext context, Offset offset,
+      TextSelection selection, Color selectionColor) {
+    final localSelection = getLocalSelection(selection);
+    assert(localSelection != null);
+    if (!localSelection.isCollapsed) {
+      final Paint paint = Paint()
+        ..color = selectionColor
+        ..style = PaintingStyle.stroke
+        ..strokeWidth = 3.0;
+      final rect =
+          Rect.fromLTWH(0.0, 0.0, _lastChildSize.width, _lastChildSize.height);
+      context.canvas.drawRect(rect.shift(offset + _childOffset), paint);
+    }
+  }
+
+  void paint(PaintingContext context, Offset offset) {
+    super.paint(context, offset + _childOffset);
+  }
+
+  static const double kHorizontalPadding = 1.0;
+
+  Size _lastChildSize;
+
+  Offset get _childOffset {
+    final dx = (size.width - _lastChildSize.width) / 2 + kHorizontalPadding;
+    final dy = (size.height - _lastChildSize.height) / 2;
+    return Offset(dx, dy);
+  }
+
+  Rect get _childRect {
+    return Rect.fromLTWH(_childOffset.dx, _childOffset.dy, _lastChildSize.width,
+        _lastChildSize.height);
+  }
+
+  @override
+  void performLayout() {
+    assert(constraints.hasBoundedWidth);
+    if (child != null) {
+      // Make constraints use 16:9 aspect ratio.
+      final width = constraints.maxWidth - kHorizontalPadding * 2;
+      final childConstraints = constraints.copyWith(
+        minWidth: 0.0,
+        maxWidth: width,
+        minHeight: 0.0,
+        maxHeight: 500, //double.infinity,
+      );
+      child.layout(childConstraints, parentUsesSize: true);
+      _lastChildSize = child.size;
+      size = Size(constraints.maxWidth, _lastChildSize.height);
+    } else {
+      performResize();
+    }
+  }
+}
diff --git a/packages/zefyr/lib/src/widgets/view.dart b/packages/zefyr/lib/src/widgets/view.dart
index 32abedbb8..9ff8e5cc3 100644
--- a/packages/zefyr/lib/src/widgets/view.dart
+++ b/packages/zefyr/lib/src/widgets/view.dart
@@ -4,7 +4,9 @@
 import 'package:flutter/material.dart';
 import 'package:meta/meta.dart';
 import 'package:notus/notus.dart';
+import 'package:zefyr/src/widgets/video.dart';
 
+import 'align.dart';
 import 'code.dart';
 import 'common.dart';
 import 'image.dart';
@@ -19,8 +21,13 @@ import 'theme.dart';
 class ZefyrView extends StatefulWidget {
   final NotusDocument document;
   final ZefyrImageDelegate imageDelegate;
+  final ZefyrVideoDelegate videoDelegate;
 
-  const ZefyrView({Key key, @required this.document, this.imageDelegate})
+  const ZefyrView(
+      {Key key,
+      @required this.document,
+      this.imageDelegate,
+      this.videoDelegate})
       : super(key: key);
 
   @override
@@ -32,17 +39,21 @@ class ZefyrViewState extends State<ZefyrView> {
   ZefyrThemeData _themeData;
 
   ZefyrImageDelegate get imageDelegate => widget.imageDelegate;
+  ZefyrVideoDelegate get videoDelegate => widget.videoDelegate;
 
   @override
   void initState() {
     super.initState();
-    _scope = ZefyrScope.view(imageDelegate: widget.imageDelegate);
+    _scope = ZefyrScope.view(
+        imageDelegate: widget.imageDelegate,
+        videoDelegate: widget.videoDelegate);
   }
 
   @override
   void didUpdateWidget(ZefyrView oldWidget) {
     super.didUpdateWidget(oldWidget);
     _scope.imageDelegate = widget.imageDelegate;
+    _scope.videoDelegate = widget.videoDelegate;
   }
 
   @override
@@ -103,6 +114,14 @@ class ZefyrViewState extends State<ZefyrView> {
       return ZefyrList(node: block);
     } else if (blockStyle == NotusAttribute.block.quote) {
       return ZefyrQuote(node: block);
+    } else if (blockStyle == NotusAttribute.block.alignLeft) {
+      return ZefyrAlign(node: block);
+    } else if (blockStyle == NotusAttribute.block.alignRight) {
+      return ZefyrAlign(node: block);
+    } else if (blockStyle == NotusAttribute.block.alignCenter) {
+      return ZefyrAlign(node: block);
+    } else if (blockStyle == NotusAttribute.block.alignJustify) {
+      return ZefyrAlign(node: block);
     }
 
     throw UnimplementedError('Block format $blockStyle.');
diff --git a/packages/zefyr/lib/zefyr.dart b/packages/zefyr/lib/zefyr.dart
index e125dc2a5..e3c1b1a83 100644
--- a/packages/zefyr/lib/zefyr.dart
+++ b/packages/zefyr/lib/zefyr.dart
@@ -9,6 +9,7 @@ library zefyr;
 
 export 'package:notus/notus.dart';
 
+export 'src/widgets/align.dart';
 export 'src/widgets/buttons.dart' hide HeadingButton, LinkButton;
 export 'src/widgets/code.dart';
 export 'src/widgets/common.dart';
@@ -27,4 +28,5 @@ export 'src/widgets/scope.dart' hide ZefyrScopeAccess;
 export 'src/widgets/selection.dart' hide SelectionHandleDriver;
 export 'src/widgets/theme.dart';
 export 'src/widgets/toolbar.dart';
+export 'src/widgets/video.dart';
 export 'src/widgets/view.dart';
diff --git a/packages/zefyr/pubspec.yaml b/packages/zefyr/pubspec.yaml
index 635aa4b54..1bf79ab63 100644
--- a/packages/zefyr/pubspec.yaml
+++ b/packages/zefyr/pubspec.yaml
@@ -5,7 +5,7 @@ author: Anatoly Pulyaevskiy <anatoly.pulyaevskiy@gmail.com>
 homepage: https://github.com/memspace/zefyr
 
 environment:
-  sdk: '>=2.2.2 <3.0.0'
+  sdk: ">=2.2.2 <3.0.0"
 
 dependencies:
   flutter:
@@ -13,7 +13,8 @@ dependencies:
   collection: ^1.14.6
   url_launcher: ^5.0.0
   quill_delta: ^1.0.0
-  notus: ^0.1.0
+  notus:
+    path: ../notus
   meta: ^1.1.0
   quiver_hashcode: ^2.0.0