diff --git a/example/lib/main.dart b/example/lib/main.dart
index 357033e..1622b49 100644
--- a/example/lib/main.dart
+++ b/example/lib/main.dart
@@ -2,7 +2,6 @@ import 'package:example/screen/cms_comments_demo.dart';
 import 'package:example/screen/github_activity_demo.dart';
 import 'package:example/screen/plain_timeline_demo.dart';
 import 'package:flutter/material.dart';
-import 'package:flutter_timeline/flutter_timeline.dart';
 
 void main() {
   runApp(TimelineDemoApp());
diff --git a/example/pubspec.lock b/example/pubspec.lock
index d6f4406..7b5468c 100644
--- a/example/pubspec.lock
+++ b/example/pubspec.lock
@@ -5,58 +5,58 @@ packages:
     dependency: transitive
     description:
       name: async
-      url: "https://pub.dartlang.org"
+      sha256: "947bfcf187f74dbc5e146c9eb9c0f10c9f8b30743e341481c1e2ed3ecc18c20c"
+      url: "https://pub.dev"
     source: hosted
-    version: "2.8.1"
+    version: "2.11.0"
   boolean_selector:
     dependency: transitive
     description:
       name: boolean_selector
-      url: "https://pub.dartlang.org"
+      sha256: "6cfb5af12253eaf2b368f07bacc5a80d1301a071c73360d746b7f2e32d762c66"
+      url: "https://pub.dev"
     source: hosted
-    version: "2.1.0"
+    version: "2.1.1"
   characters:
     dependency: transitive
     description:
       name: characters
-      url: "https://pub.dartlang.org"
+      sha256: "04a925763edad70e8443c99234dc3328f442e811f1d8fd1a72f1c8ad0f69a605"
+      url: "https://pub.dev"
     source: hosted
-    version: "1.1.0"
-  charcode:
-    dependency: transitive
-    description:
-      name: charcode
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.3.1"
+    version: "1.3.0"
   clock:
     dependency: transitive
     description:
       name: clock
-      url: "https://pub.dartlang.org"
+      sha256: cb6d7f03e1de671e34607e909a7213e31d7752be4fb66a86d29fe1eb14bfb5cf
+      url: "https://pub.dev"
     source: hosted
-    version: "1.1.0"
+    version: "1.1.1"
   collection:
     dependency: transitive
     description:
       name: collection
-      url: "https://pub.dartlang.org"
+      sha256: "4a07be6cb69c84d677a6c3096fcf960cc3285a8330b4603e0d463d15d9bd934c"
+      url: "https://pub.dev"
     source: hosted
-    version: "1.15.0"
+    version: "1.17.1"
   expandable:
     dependency: "direct main"
     description:
       name: expandable
-      url: "https://pub.dartlang.org"
+      sha256: "9604d612d4d1146dafa96c6d8eec9c2ff0994658d6d09fed720ab788c7f5afc2"
+      url: "https://pub.dev"
     source: hosted
-    version: "4.1.4"
+    version: "5.0.1"
   fake_async:
     dependency: transitive
     description:
       name: fake_async
-      url: "https://pub.dartlang.org"
+      sha256: "511392330127add0b769b75a987850d136345d9227c6b94c96a04cf4a391bf78"
+      url: "https://pub.dev"
     source: hosted
-    version: "1.2.0"
+    version: "1.3.1"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -74,27 +74,46 @@ packages:
       relative: true
     source: path
     version: "0.3.0"
+  js:
+    dependency: transitive
+    description:
+      name: js
+      sha256: f2c445dce49627136094980615a031419f7f3eb393237e4ecd97ac15dea343f3
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.6.7"
   matcher:
     dependency: transitive
     description:
       name: matcher
-      url: "https://pub.dartlang.org"
+      sha256: "6501fbd55da300384b768785b83e5ce66991266cec21af89ab9ae7f5ce1c4cbb"
+      url: "https://pub.dev"
     source: hosted
-    version: "0.12.10"
+    version: "0.12.15"
+  material_color_utilities:
+    dependency: transitive
+    description:
+      name: material_color_utilities
+      sha256: d92141dc6fe1dad30722f9aa826c7fbc896d021d792f80678280601aff8cf724
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.2.0"
   meta:
     dependency: transitive
     description:
       name: meta
-      url: "https://pub.dartlang.org"
+      sha256: "3c74dbf8763d36539f114c799d8a2d87343b5067e9d796ca22b5eb8437090ee3"
+      url: "https://pub.dev"
     source: hosted
-    version: "1.7.0"
+    version: "1.9.1"
   path:
     dependency: transitive
     description:
       name: path
-      url: "https://pub.dartlang.org"
+      sha256: "8829d8a55c13fc0e37127c29fedf290c102f4e40ae94ada574091fe0ff96c917"
+      url: "https://pub.dev"
     source: hosted
-    version: "1.8.0"
+    version: "1.8.3"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -104,58 +123,58 @@ packages:
     dependency: transitive
     description:
       name: source_span
-      url: "https://pub.dartlang.org"
+      sha256: dd904f795d4b4f3b870833847c461801f6750a9fa8e61ea5ac53f9422b31f250
+      url: "https://pub.dev"
     source: hosted
-    version: "1.8.1"
+    version: "1.9.1"
   stack_trace:
     dependency: transitive
     description:
       name: stack_trace
-      url: "https://pub.dartlang.org"
+      sha256: c3c7d8edb15bee7f0f74debd4b9c5f3c2ea86766fe4178eb2a18eb30a0bdaed5
+      url: "https://pub.dev"
     source: hosted
-    version: "1.10.0"
+    version: "1.11.0"
   stream_channel:
     dependency: transitive
     description:
       name: stream_channel
-      url: "https://pub.dartlang.org"
+      sha256: "83615bee9045c1d322bbbd1ba209b7a749c2cbcdcb3fdd1df8eb488b3279c1c8"
+      url: "https://pub.dev"
     source: hosted
-    version: "2.1.0"
+    version: "2.1.1"
   string_scanner:
     dependency: transitive
     description:
       name: string_scanner
-      url: "https://pub.dartlang.org"
+      sha256: "556692adab6cfa87322a115640c11f13cb77b3f076ddcc5d6ae3c20242bedcde"
+      url: "https://pub.dev"
     source: hosted
-    version: "1.1.0"
+    version: "1.2.0"
   term_glyph:
     dependency: transitive
     description:
       name: term_glyph
-      url: "https://pub.dartlang.org"
+      sha256: a29248a84fbb7c79282b40b8c72a1209db169a2e0542bce341da992fe1bc7e84
+      url: "https://pub.dev"
     source: hosted
-    version: "1.2.0"
+    version: "1.2.1"
   test_api:
     dependency: transitive
     description:
       name: test_api
-      url: "https://pub.dartlang.org"
+      sha256: eb6ac1540b26de412b3403a163d919ba86f6a973fe6cc50ae3541b80092fdcfb
+      url: "https://pub.dev"
     source: hosted
-    version: "0.4.2"
-  typed_data:
-    dependency: transitive
-    description:
-      name: typed_data
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.3.0"
+    version: "0.5.1"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
-      url: "https://pub.dartlang.org"
+      sha256: "80b3257d1492ce4d091729e3a67a60407d227c27241d6927be0130c98e741803"
+      url: "https://pub.dev"
     source: hosted
-    version: "2.1.0"
+    version: "2.1.4"
 sdks:
-  dart: ">=2.12.0 <3.0.0"
-  flutter: ">=1.12.0"
+  dart: ">=3.0.0-0 <=3.0.0"
+  flutter: ">=2.0.0"
diff --git a/example/pubspec.yaml b/example/pubspec.yaml
index db80333..de921b5 100644
--- a/example/pubspec.yaml
+++ b/example/pubspec.yaml
@@ -18,7 +18,7 @@ publish_to: 'none' # Remove this line if you wish to publish to pub.dev
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.12.0 <3.0.0"
+  sdk: ">=2.12.0 <=3.0.0"
 
 dependencies:
   flutter:
@@ -27,7 +27,7 @@ dependencies:
   flutter_timeline:
     path: "../"
 
-  expandable: ^4.1.4
+  expandable: ^5.0.1
 
 dev_dependencies:
   flutter_test:
diff --git a/lib/defaults.dart b/lib/defaults.dart
index be826c4..bb15530 100644
--- a/lib/defaults.dart
+++ b/lib/defaults.dart
@@ -12,7 +12,7 @@ class TimelineDots {
   Widget get simple {
     return Container(
       decoration: BoxDecoration(
-        color: Theme.of(context).accentColor,
+        color: Theme.of(context).colorScheme.secondary,
         image: null,
         shape: BoxShape.circle,
       ),
@@ -22,7 +22,7 @@ class TimelineDots {
   Widget get borderDot {
     return Container(
       decoration: BoxDecoration(
-          color: Theme.of(context).accentColor,
+          color: Theme.of(context).colorScheme.secondary,
           image: null,
           borderRadius: BorderRadius.all(Radius.circular(16)),
           border: Border.all()),
@@ -72,7 +72,7 @@ class TimelineDots {
       height: 12,
       width: 12,
       decoration: BoxDecoration(
-        color: Theme.of(context).accentColor,
+        color: Theme.of(context).colorScheme.secondary,
         image: null,
         shape: BoxShape.circle,
       ),
diff --git a/pubspec.lock b/pubspec.lock
index 8077d23..9cdb37b 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -5,51 +5,50 @@ packages:
     dependency: transitive
     description:
       name: async
-      url: "https://pub.dartlang.org"
+      sha256: "947bfcf187f74dbc5e146c9eb9c0f10c9f8b30743e341481c1e2ed3ecc18c20c"
+      url: "https://pub.dev"
     source: hosted
-    version: "2.8.1"
+    version: "2.11.0"
   boolean_selector:
     dependency: transitive
     description:
       name: boolean_selector
-      url: "https://pub.dartlang.org"
+      sha256: "6cfb5af12253eaf2b368f07bacc5a80d1301a071c73360d746b7f2e32d762c66"
+      url: "https://pub.dev"
     source: hosted
-    version: "2.1.0"
+    version: "2.1.1"
   characters:
     dependency: transitive
     description:
       name: characters
-      url: "https://pub.dartlang.org"
+      sha256: "04a925763edad70e8443c99234dc3328f442e811f1d8fd1a72f1c8ad0f69a605"
+      url: "https://pub.dev"
     source: hosted
-    version: "1.1.0"
-  charcode:
-    dependency: transitive
-    description:
-      name: charcode
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.3.1"
+    version: "1.3.0"
   clock:
     dependency: transitive
     description:
       name: clock
-      url: "https://pub.dartlang.org"
+      sha256: cb6d7f03e1de671e34607e909a7213e31d7752be4fb66a86d29fe1eb14bfb5cf
+      url: "https://pub.dev"
     source: hosted
-    version: "1.1.0"
+    version: "1.1.1"
   collection:
     dependency: transitive
     description:
       name: collection
-      url: "https://pub.dartlang.org"
+      sha256: "4a07be6cb69c84d677a6c3096fcf960cc3285a8330b4603e0d463d15d9bd934c"
+      url: "https://pub.dev"
     source: hosted
-    version: "1.15.0"
+    version: "1.17.1"
   fake_async:
     dependency: transitive
     description:
       name: fake_async
-      url: "https://pub.dartlang.org"
+      sha256: "511392330127add0b769b75a987850d136345d9227c6b94c96a04cf4a391bf78"
+      url: "https://pub.dev"
     source: hosted
-    version: "1.2.0"
+    version: "1.3.1"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -60,27 +59,46 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  js:
+    dependency: transitive
+    description:
+      name: js
+      sha256: f2c445dce49627136094980615a031419f7f3eb393237e4ecd97ac15dea343f3
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.6.7"
   matcher:
     dependency: transitive
     description:
       name: matcher
-      url: "https://pub.dartlang.org"
+      sha256: "6501fbd55da300384b768785b83e5ce66991266cec21af89ab9ae7f5ce1c4cbb"
+      url: "https://pub.dev"
     source: hosted
-    version: "0.12.10"
+    version: "0.12.15"
+  material_color_utilities:
+    dependency: transitive
+    description:
+      name: material_color_utilities
+      sha256: d92141dc6fe1dad30722f9aa826c7fbc896d021d792f80678280601aff8cf724
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.2.0"
   meta:
     dependency: transitive
     description:
       name: meta
-      url: "https://pub.dartlang.org"
+      sha256: "3c74dbf8763d36539f114c799d8a2d87343b5067e9d796ca22b5eb8437090ee3"
+      url: "https://pub.dev"
     source: hosted
-    version: "1.7.0"
+    version: "1.9.1"
   path:
     dependency: transitive
     description:
       name: path
-      url: "https://pub.dartlang.org"
+      sha256: "8829d8a55c13fc0e37127c29fedf290c102f4e40ae94ada574091fe0ff96c917"
+      url: "https://pub.dev"
     source: hosted
-    version: "1.8.0"
+    version: "1.8.3"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -90,57 +108,57 @@ packages:
     dependency: transitive
     description:
       name: source_span
-      url: "https://pub.dartlang.org"
+      sha256: dd904f795d4b4f3b870833847c461801f6750a9fa8e61ea5ac53f9422b31f250
+      url: "https://pub.dev"
     source: hosted
-    version: "1.8.1"
+    version: "1.9.1"
   stack_trace:
     dependency: transitive
     description:
       name: stack_trace
-      url: "https://pub.dartlang.org"
+      sha256: c3c7d8edb15bee7f0f74debd4b9c5f3c2ea86766fe4178eb2a18eb30a0bdaed5
+      url: "https://pub.dev"
     source: hosted
-    version: "1.10.0"
+    version: "1.11.0"
   stream_channel:
     dependency: transitive
     description:
       name: stream_channel
-      url: "https://pub.dartlang.org"
+      sha256: "83615bee9045c1d322bbbd1ba209b7a749c2cbcdcb3fdd1df8eb488b3279c1c8"
+      url: "https://pub.dev"
     source: hosted
-    version: "2.1.0"
+    version: "2.1.1"
   string_scanner:
     dependency: transitive
     description:
       name: string_scanner
-      url: "https://pub.dartlang.org"
+      sha256: "556692adab6cfa87322a115640c11f13cb77b3f076ddcc5d6ae3c20242bedcde"
+      url: "https://pub.dev"
     source: hosted
-    version: "1.1.0"
+    version: "1.2.0"
   term_glyph:
     dependency: transitive
     description:
       name: term_glyph
-      url: "https://pub.dartlang.org"
+      sha256: a29248a84fbb7c79282b40b8c72a1209db169a2e0542bce341da992fe1bc7e84
+      url: "https://pub.dev"
     source: hosted
-    version: "1.2.0"
+    version: "1.2.1"
   test_api:
     dependency: transitive
     description:
       name: test_api
-      url: "https://pub.dartlang.org"
+      sha256: eb6ac1540b26de412b3403a163d919ba86f6a973fe6cc50ae3541b80092fdcfb
+      url: "https://pub.dev"
     source: hosted
-    version: "0.4.2"
-  typed_data:
-    dependency: transitive
-    description:
-      name: typed_data
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.3.0"
+    version: "0.5.1"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
-      url: "https://pub.dartlang.org"
+      sha256: "80b3257d1492ce4d091729e3a67a60407d227c27241d6927be0130c98e741803"
+      url: "https://pub.dev"
     source: hosted
-    version: "2.1.0"
+    version: "2.1.4"
 sdks:
-  dart: ">=2.12.0 <3.0.0"
+  dart: ">=3.0.0-0 <=3.0.0"
diff --git a/pubspec.yaml b/pubspec.yaml
index 541790b..d4e0902 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,12 +1,12 @@
 name: flutter_timeline
 description: a fully customizable & general timeline widget, based on real-world application references
-version: 0.3.0
+version: 0.3.1
 homepage: https://github.com/softmarshmallow/flutter-timeline
 repository: https://github.com/softmarshmallow/flutter-timeline
 license: MIT
 
 environment:
-  sdk: ">=2.12.0 <3.0.0"
+  sdk: ">=2.12.0 <=4.0.0"
 
 dependencies:
   flutter:
diff --git a/test/flutter_timeline_test.dart b/test/flutter_timeline_test.dart
index 0d5d06f..3fcdc9e 100644
--- a/test/flutter_timeline_test.dart
+++ b/test/flutter_timeline_test.dart
@@ -1,6 +1,5 @@
 import 'package:flutter_test/flutter_test.dart';
 
-import 'package:flutter_timeline/flutter_timeline.dart';
 
 void main() {
   test('empty', () {