improve(ux): WIP support place fold arrow on the right of block container

src/main/frontend/components/block.css

@@ -1,4 +1,6 @@
 .block-content-wrapper {
+  @apply border border-red-400;
+
   /* 38px is the width of block-control */
   width: calc(100% - 22px);
 
@@ -9,6 +11,8 @@
 }
 
 .block-content {
+  @apply border border-blue-400;
+
   min-height: 24px;
   max-width: 100%;
   overflow: initial;
@@ -323,6 +327,8 @@
 }
 
 .ls-block {
+  @apply border border-dashed border-green-600;
+  
   position: relative;
   min-height: 24px;
   padding: 2px 0;
@@ -648,4 +654,4 @@ html.is-mac {
       cursor: pointer;
     }
   }
-}
+}