diff --git a/lib/detector/detector.dart b/lib/detector/detector.dart
index ffd3602..851491f 100644
--- a/lib/detector/detector.dart
+++ b/lib/detector/detector.dart
@@ -3,7 +3,7 @@ import 'package:flutter/cupertino.dart';
 import 'hashtag_regular_expression.dart';
 
 /// DataModel to explain the unit of word in detection system
-class Detection extends Comparable<Detection> {
+class Detection implements Comparable<Detection> {
   Detection({required this.range, this.style, this.emojiStartPoint});
 
   final TextRange range;
diff --git a/lib/widgets/hashtag_text_field.dart b/lib/widgets/hashtag_text_field.dart
index ab6c47f..39b2bd8 100644
--- a/lib/widgets/hashtag_text_field.dart
+++ b/lib/widgets/hashtag_text_field.dart
@@ -1024,7 +1024,7 @@ class _HashTagTextFieldState extends State<HashTagTextField>
       return effectiveDecoration.copyWith(
         errorText: effectiveDecoration.errorText ?? '',
         counterStyle: effectiveDecoration.errorStyle ??
-            themeData.textTheme.caption!.copyWith(color: themeData.errorColor),
+            themeData.textTheme.bodySmall!.copyWith(color: themeData.colorScheme.error),
         counterText: counterText,
         semanticCounterText: semanticCounterText,
       );
@@ -1197,9 +1197,9 @@ class _HashTagTextFieldState extends State<HashTagTextField>
     final ThemeData theme = Theme.of(context);
     final TextSelectionThemeData selectionTheme =
         TextSelectionTheme.of(context);
-    final TextStyle style = theme.textTheme.subtitle1!.merge(widget.basicStyle);
+    final TextStyle style = theme.textTheme.titleMedium!.merge(widget.basicStyle);
     final Brightness keyboardAppearance =
-        widget.keyboardAppearance ?? theme.primaryColorBrightness;
+        widget.keyboardAppearance ?? theme.brightness;
     final TextEditingController controller = _effectiveController;
     final FocusNode focusNode = _effectiveFocusNode;
     final List<TextInputFormatter> formatters = <TextInputFormatter>[
diff --git a/pubspec.yaml b/pubspec.yaml
index 6647c1e..91d7681 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,12 +1,11 @@
 name: hashtagable
 description: Widgets and functions to implement hashtag decorated text. Decorates the words which start with `#` like a Twitter.
-version: 2.3.0+1
+version: 2.3.1+1
 homepage: https://github.com/santa112358/hashtagable
 repository: https://github.com/santa112358/hashtagable
 
 environment:
-  sdk: ">=2.16.1 <3.0.0"
-  flutter: "2.10.3"
+  sdk: ">=3.0.0 <4.0.0"
 
 dependencies:
   flutter: