enhance(ui): add hint class for the blank content block

src/main/frontend/components/block.cljs

@@ -2796,7 +2796,8 @@
         :class (str uuid
                     (when pre-block? " pre-block")
                     (when (and card? (not review-cards?)) " shadow-md")
-                    (when selected? " selected noselect"))
+                    (when selected? " selected noselect")
+                    (when (string/blank? content) " is-blank"))
         :blockid (str uuid)
         :haschild (str (boolean has-child?))}
 

src/main/frontend/components/block.css

@@ -345,6 +345,7 @@
 
   &.selected {
     border-bottom-color: var(--ls-primary-background-color);
+    border-radius: 2px;
 
     &:last-child {
       border-bottom-color: transparent;