style(editor): customize scrollbar appearance and improve badge layout styles

templates/index.html

@@ -30,7 +30,7 @@
           <span class="devcm-ascii-badge__grid"></span>
           <div class="devcm-ascii-badge__inner">
             <span class="devcm-ascii-badge__label">DEV.CM</span>
-            <pre>
+            <pre th:utext="'DEV&#10;CM'">
 DEV
 CM</pre
             >