Add stylesheet to template

Change-Id: I351f3efd44af5503f1766de9129a2a5d0bb933ac
diff --git a/templates/main.html b/templates/main.html
index 7c707c9..cdde2fa 100644
--- a/templates/main.html
+++ b/templates/main.html
@@ -2,6 +2,7 @@
 <html>
   <head>
     <title>External Provider</title>
+    <link href="https://korap.ids-mannheim.de/instance/test/css/kalamar-plugin-latest.css" type="text/css" rel="stylesheet" />
     <script data-server="{{ .korapServer }}" src="https://korap.ids-mannheim.de/instance/test/js/korap-plugin-latest.js"></script>
   </head>
   <body>