ADD: <kbd> tag style.

Author: ivan-nginx

source/css/_common/scaffolding/base.styl

@@ -98,4 +98,13 @@ dd {
   padding: 0;
 }
 
-
+kbd {
+  border: 1px solid $grey-light;
+  border-radius: 0.2em;
+  box-shadow: 0.1em 0.1em 0.2em rgba(0,0,0,0.1);
+  background-color: #f9f9f9;
+  font-family: inherit;
+  background-image: -webkit-linear-gradient(top, #eee, white, #eee);
+  padding: 0.1em 0.3em;
+  white-space: nowrap;
+}