feat(markdown): add styling for heading tag

Author: dewita

assets/css/_markdown-style.scss

@@ -11,6 +11,20 @@
     font-size: 1.3em;
   }
 
+  h2 {
+    margin-bottom: 10px;
+    margin-top: 30px;
+
+    ~ h3 {
+      margin-top: 20px;
+    }
+  }
+
+
+  h3 {
+    font-size: .975em;
+  }
+
   img {
     margin-top: 20px;
     margin-bottom: 20px;