feat: add dde_button widget.

app/lib/widgets/dde_button.dart

@@ -0,0 +1,54 @@
+import 'package:dde_gesture_manager/constants/constants.dart';
+import 'package:flutter/material.dart';
+import 'package:glass_kit/glass_kit.dart';
+
+class DButton extends StatefulWidget {
+  final double width;
+  final double height;
+  final Widget child;
+  final GestureTapCallback? onTap;
+
+  const DButton({
+    Key? key,
+    required this.width,
+    this.height = defaultButtonHeight,
+    required this.child,
+    this.onTap,
+  }) : super(key: key);
+
+  @override
+  State<DButton> createState() => _DButtonState();
+}
+
+class _DButtonState extends State<DButton> {
+  bool _hovering = false;
+
+  @override
+  Widget build(BuildContext context) {
+    return GestureDetector(
+      onTap: widget.onTap,
+      child: GlassContainer(
+        width: widget.width,
+        height: widget.height,
+        gradient: LinearGradient(
+          colors: [Colors.white.withOpacity(_hovering ? 0.1 : 0.15), Colors.white.withOpacity(0.1)],
+          begin: Alignment.topCenter,
+          end: Alignment.bottomCenter,
+        ),
+        borderColor: Color(0xff565656),
+        borderWidth: 1,
+        borderRadius: BorderRadius.circular(defaultBorderRadius),
+        child: MouseRegion(
+          onEnter: (event) => setState(() {
+            _hovering = true;
+          }),
+          onExit: (event) => setState(() {
+            _hovering = false;
+          }),
+          cursor: SystemMouseCursors.click,
+          child: Center(child: widget.child),
+        ),
+      ),
+    );
+  }
+}

app/lib/widgets/help_button.dart

@@ -0,0 +1,28 @@
+import 'package:dde_gesture_manager/extensions.dart';
+import 'package:flutter/material.dart';
+
+class HelpButton extends StatelessWidget {
+  const HelpButton({Key? key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return GestureDetector(
+      onTap: () {},
+      child: MouseRegion(
+        cursor: SystemMouseCursors.click,
+        child: Tooltip(
+          message: LocaleKeys.help_tip.tr(),
+          child: Row(
+            children: [
+              Icon(Icons.help_outline, size: 20),
+              Padding(
+                padding: const EdgeInsets.symmetric(horizontal: 3),
+                child: Text(LocaleKeys.help_label).tr(),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}

app/lib/widgets/language_switcher.dart

@@ -1,3 +1,4 @@
+import 'package:collection/collection.dart';
 import 'package:dde_gesture_manager/constants/sp_keys.dart';
 import 'package:dde_gesture_manager/constants/supported_locales.dart';
 import 'package:dde_gesture_manager/extensions.dart';
@@ -6,7 +7,6 @@ import 'package:dde_gesture_manager/utils/helper.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
-import 'package:collection/collection.dart';
 import 'package:window_manager/window_manager.dart';
 
 class LanguageSwitcher extends StatelessWidget {
@@ -18,6 +18,7 @@ class LanguageSwitcher extends StatelessWidget {
     var _supportedLocale = supportedLocales.firstWhereOrNull((element) => element == _locale);
 
     return PopupMenuButton<SupportedLocale>(
+    tooltip: LocaleKeys.language_tip.tr(),
       child: Row(
         children: [
           Icon(Icons.language_outlined, size: 20),

app/lib/widgets/theme_switcher.dart

@@ -1,9 +1,9 @@
+import 'package:dde_gesture_manager/extensions.dart';
 import 'package:dde_gesture_manager/generated/locale_keys.g.dart';
 import 'package:dde_gesture_manager/models/configs.dart';
 import 'package:dde_gesture_manager/models/configs.provider.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
-import 'package:dde_gesture_manager/extensions.dart';
 
 class ThemeSwitcher extends StatelessWidget {
   const ThemeSwitcher({Key? key}) : super(key: key);
@@ -23,7 +23,7 @@ class ThemeSwitcher extends StatelessWidget {
         ],
       ),
       padding: EdgeInsets.zero,
-      tooltip: LocaleKeys.theme_label.tr(),
+      tooltip: LocaleKeys.theme_tip.tr(),
       itemBuilder: (BuildContext context) => [
         PopupMenuItem<BrightnessMode>(
           child: ListTile(