add name change warning and tweak some styles to fit

src/index.njk

@@ -3,6 +3,8 @@ title: Fediverse Skillshare Classifieds
 ---
 {% css %}{% include "css/listings.css" %}{% endcss %}
 
+<h2>Soon to become FediLearns!</h2>
+
 <div id="jump-links">
   <h2>jump to...</h2>
   <ul>