Move inline CSS to stylesheet

Author: stomar

_includes/unmaintained.html

@@ -1,10 +1,10 @@
-<p style="color: #c61a1a; font-size: 125%">
+<p class="warning">
 This translation of www.ruby-lang.org is unmaintained
 and might contain obsolete information or even errors.
 Please refer to the <a href="/en/">original English site</a>
 for the most up-to-date content.
 </p>
-<p style="color: #c61a1a; font-size: 125%">
+<p class="warning">
 If you want to contribute and help improve this site,
 please visit the <a href="https://github.com/ruby/www.ruby-lang.org/">project's page on GitHub</a>.
 </p>

stylesheets/shared.css

@@ -64,6 +64,10 @@ body {
 #footer {
   clear: both;
 }
+.warning {
+  color: #c61a1a;
+  font-size: 125%;
+}
 
 
 /* layouts */