Update cover.css

Moved the inset box-shadow to .site-wrapper in order to keep the shadow at the edges even if content exceeds viewport and needs scrolling.

docs/examples/cover/cover.css

@@ -33,8 +33,6 @@ body {
   color: #fff;
   text-align: center;
   text-shadow: 0 1px 3px rgba(0,0,0,.5);
-  -webkit-box-shadow: inset 0 0 100px rgba(0,0,0,.5);
-          box-shadow: inset 0 0 100px rgba(0,0,0,.5);
 }
 
 /* Extra markup and styles for table-esque vertical and horizontal centering */
@@ -43,6 +41,8 @@ body {
   width: 100%;
   height: 100%; /* For at least Firefox */
   min-height: 100%;
+  -webkit-box-shadow: inset 0 0 100px rgba(0,0,0,.5);
+          box-shadow: inset 0 0 100px rgba(0,0,0,.5);
 }
 .site-wrapper-inner {
   display: table-cell;