diff --git a/index.html b/index.html
index 7e55625..11f8ee1 100644
--- a/index.html
+++ b/index.html
@@ -12,6 +12,12 @@
   <!-- Theme used for syntax highlighting of code -->
   <link rel="stylesheet" href="lib/css/zenburn.css">
   
+  <!-- User style -->
+  <style>
+    .red { color: #ff2c2d; }
+    .green { color: #17ff2e; }
+    .blue { color: #1b91ff; }
+  </style>
   <!-- Printing and PDF exports -->
   <script>
     var link = document.createElement( 'link' );