feat: update embed block style

Author: realth000

lib/src/embed_piece_container.dart

@@ -35,7 +35,7 @@ class EmbedPieceContainer extends StatelessWidget {
       constraints: const BoxConstraints(minHeight: 40),
       child: Card(
         margin: EdgeInsets.zero,
-        // color: Colors.transparent,
+        color: Theme.of(context).colorScheme.surfaceContainerHigh,
         shape: ContinuousRectangleBorder(
           borderRadius:
               pieceType == EmbedPieceType.header

lib/src/tags/free/free_builder.dart

@@ -12,7 +12,7 @@ final class BBCodeFreeHeaderEmbedBuilder extends EmbedBuilder {
   }
 
   @override
-  bool get expanded => false;
+  bool get expanded => true;
 
   @override
   String get key => BBCodeFreeKeys.headerType;
@@ -51,7 +51,7 @@ final class BBCodeFreeTailEmbedBuilder extends EmbedBuilder {
   }
 
   @override
-  bool get expanded => false;
+  bool get expanded => true;
 
   @override
   String get key => BBCodeFreeKeys.tailType;

lib/src/tags/hide_v2/hide_v2_builder.dart

@@ -13,7 +13,7 @@ final class BBCodeHideV2HeaderEmbedBuilder extends EmbedBuilder {
   }
 
   @override
-  bool get expanded => false;
+  bool get expanded => true;
 
   @override
   String get key => BBCodeHideV2Keys.headerType;
@@ -33,7 +33,7 @@ final class BBCodeHideV2TailEmbedBuilder extends EmbedBuilder {
   }
 
   @override
-  bool get expanded => false;
+  bool get expanded => true;
 
   @override
   String get key => BBCodeHideV2Keys.tailType;

lib/src/tags/spoiler_v2/spoiler_v2_builder.dart

@@ -27,7 +27,7 @@ final class BBCodeSpoilerV2HeaderEmbedBuilder extends EmbedBuilder {
   }
 
   @override
-  bool get expanded => false;
+  bool get expanded => true;
 
   @override
   String get key => BBCodeSpoilerV2Keys.headerType;
@@ -47,7 +47,7 @@ final class BBCodeSpoilerV2TailEmbedBuilder extends EmbedBuilder {
   }
 
   @override
-  bool get expanded => false;
+  bool get expanded => true;
 
   @override
   String get key => BBCodeSpoilerV2Keys.tailType;