Add customization options for padding in chat area (#628)

Co-authored-by: Georgiy Voloshin <[email protected]>

lib/src/chat_theme.dart

@@ -61,6 +61,7 @@ abstract class ChatTheme {
     required this.backgroundColor,
     this.bubbleMargin,
     required this.dateDividerMargin,
+    required this.chatContentMargin,
     required this.dateDividerTextStyle,
     required this.deliveredIcon,
     required this.documentIcon,
@@ -132,6 +133,9 @@ abstract class ChatTheme {
   /// Margin around date dividers.
   final EdgeInsets dateDividerMargin;
 
+  /// Margin inside chat area.
+  final EdgeInsets chatContentMargin;
+
   /// Text style of the date dividers.
   final TextStyle dateDividerTextStyle;
 
@@ -325,6 +329,9 @@ class DefaultChatTheme extends ChatTheme {
       bottom: 32,
       top: 16,
     ),
+    super.chatContentMargin = const EdgeInsets.only(
+      bottom: 4,
+    ),
     super.dateDividerTextStyle = const TextStyle(
       color: neutral2,
       fontSize: 12,
@@ -499,6 +506,9 @@ class DarkChatTheme extends ChatTheme {
       bottom: 32,
       top: 16,
     ),
+    super.chatContentMargin = const EdgeInsets.only(
+      bottom: 4,
+    ),
     super.dateDividerTextStyle = const TextStyle(
       color: neutral7,
       fontSize: 12,

lib/src/widgets/chat_list.dart

@@ -296,7 +296,7 @@ class _ChatListState extends State<ChatList>
               ),
             ),
             SliverPadding(
-              padding: const EdgeInsets.only(bottom: 4),
+              padding: InheritedChatTheme.of(context).theme.chatContentMargin,
               sliver: SliverAnimatedList(
                 findChildIndexCallback: (Key key) {
                   if (key is ValueKey<Object>) {