restyle new user invite email

src/metabase/email/new_user_invite.mustache

 {{> metabase/email/_header }}
-  <div style="padding: 2em 4em; border: 1px solid #dddddd; border-radius: 2px; background-color: white; box-shadow: 0 1px 2px rgba(0, 0, 0, .08); text-align: center;">
+  <div style="text-align: center;">
     <div style="padding-bottom: 1em;">
-      <h2 style="font-weight: normal; color: #4C545B;line-height: 1.65rem;">{{invitedName}}, you're invited to {{company}}'s&nbsp;Metabase</h2>
-      <h4 style="font-weight: normal;"><a style="color: #4A90E2; text-decoration: none;" href="mailto:{{invitorEmail}}">{{invitorName}} ({{invitorEmail}})</a> invited you to join them.</h4>
+      <h2 style="font-weight: normal; color: #4C545B;line-height: 1.65rem;">{{invitorName}} wants you to join them on {{company}}'s&nbsp;Metabase</h2>
+
+      <!--h4 style="font-weight: normal;"><a style="color: #4A90E2; text-decoration: none;" href="mailto:{{invitorEmail}}">{{invitorName}} ({{invitorEmail}})</a> invited you to join them.</h4-->
+
     </div>
     <div style="border-top: 1px solid #ededed; border-bottom: 1px solid #ededed; padding: 3em 0em 2em 0em; text-align: center; margin-left: auto; margin-right: auto; max-width: 400px; position: relative;">
       <table width="296" height="141" cellpadding="0" cellspacing="0" style="display:block;margin:0 auto;">
@@ -13,10 +15,10 @@
           <td height="15" width="168"><img src="http://static.metabase.com/email_graph_right.png" width="168" height="15" style="display:block" /></td></tr>
         <tr><td colspan="3" height="46"><img src="http://static.metabase.com/email_graph_bottom.png" width="296" height="56" style="display:block" /></td></tr>
       </table>
-      <p style="line-height: 1.3rem;">{{invitedName}}'s Happiness and Productivity Over&nbsp;Time</p>
+      <p style="line-height: 1.3rem; font-size: small">{{invitedName}}'s Happiness and Productivity Over&nbsp;Time</p>
     </div>
-    <div style="max-width: 400px; margin-left: auto; margin-right: auto; padding-top: 1em; line-height: 1.2rem;">
-      <p>Metabase is a simple and powerful analytics tool which lets <span style="color: #595959;">anyone</span> learn and <span style="color: #595959;">make decisions</span> from their company's data.</p>
+    <div style="text-align: left; max-width: 400px; margin-left: auto; margin-right: auto; padding-top: 1em; line-height: 1.2rem;">
+      <p>Metabase is a simple and powerful analytics tool which lets <b>anyone</b> learn and <b>make decisions</b> from their company's data.</p>
       <p>No technical knowledge required!</p>
     </div>
     <div style="padding: 1em;">