refactor(.back): move styles into dedicated file

Author: sarmstead

src/css/app.css

@@ -7,6 +7,7 @@
 @import './components/sponsors.css';
 @import './components/profile-image.css';
 @import './components/static-content.css';
+@import './components/back.css';
 
 /* /1* Layout *1/ */
 @import './layout/navigation.css';

src/css/components/back.css

@@ -0,0 +1,5 @@
+.back {
+    font-size: 16px;
+    display: inline-block;
+    margin: 0 0 20px 0;
+}

src/css/rubycentral.css

@@ -49,12 +49,6 @@ h3 {
   margin: 0 0 5px 0;
 }
 
-.back {
-  font-size: 16px;
-  display: inline-block;
-  margin: 0 0 20px 0;
-}
-
 .arrow {
   display: none;
 }