Rename {common => base}.css.

Change-Id: I5099a8d8c955ae2d8f200b22678283b1985ddd7e
diff --git a/src/main/resources/templates/base.html b/src/main/resources/templates/base.html
index 408424d..598c6c8 100644
--- a/src/main/resources/templates/base.html
+++ b/src/main/resources/templates/base.html
@@ -5,7 +5,7 @@
 
   <title>{#insert title}{/}</title>
 
-  <link rel="stylesheet" type="text/css" href="/common.css" />
+  <link rel="stylesheet" type="text/css" href="/base.css" />
   <script type="module" src="/components.js"></script>
 
   {#insert head}{/}