Add showing tunit boundaries

assets/css/article.css

@@ -6,11 +6,32 @@
   @apply hover:bg-gray-300;
 }
 
+.article a.hide-link {
+  display: none;
+}
+
+.article.show-boundary a.hide-link {
+  display: inline;
+}
+
+.article.show-boundary a.show-link {
+  display: none;
+}
+
+.article.show-boundary span + span.tunit::before {
+  content: "🭱";
+  color: brown;
+  font-weight: bold;
+  font-size: 130%;
+  vertical-align: -2px;
+}
+
+
 .article h4 {
   @apply font-semibold text-lg leading-8 text-zinc-800;
 }
 
-.article p {
+.article p, .article div {
   @apply text-justify;
 }