add notice class to call to action

Author: StevenClontz

index.html

@@ -60,11 +60,11 @@
 sociotechnical infrastructure: software, databases, communities, and more.
       </p>
 
-      <p>
-<strong>Get involved!</strong> The best way to connect with our
+      <p class="notice">
+<strong>Get involved!</strong> The best way to engage with our
 community is to join our
 <a href="https://code4math.zulipchat.com">Zulip chat</a>.
-We look forward to hearing from you!
+We look forward to connecting with you!
       </p>
 
 <h2 id="principles">Our principles</h2>