Minor presentation tweaks on /fx and /mobile/features

Fixed gap under tablet image on /fx
Removed left border on first sub-item
Some spacing adjustments on mobile features

media/css/firefox/fx.less

@@ -166,6 +166,11 @@
         vertical-align: top;
         background: url(/media/img/firefox/fx/android-four-stars.png) center top no-repeat;
     }
+    .sub-features {
+        margin-top: -50px;
+        background-color: #fafafa;
+        position: relative;
+    }
 }
 
 .sub-features {
@@ -216,6 +221,7 @@
         }
     }
     li:first-child a.link,
+    li:first-child a.mobile-link,
     li:first-child span.link,
     li:first-child .wrap {
         border-left: 0;
@@ -334,6 +340,7 @@
     .sub-features,
     .mobile-content .sub-features {
         width: auto;
+        margin-top: 0;
         li {
             
             float: none;

media/css/firefox/mobile-features.less

@@ -82,10 +82,10 @@
 
 #get {
     display: block;
-    padding: 10px 0 0 @gridColumnWidth;
+    padding: 25px 0 0 @gridColumnWidth;
     float: left;
     border-top: 1px dotted @borderColor;
-    background: 7px 10px url(/media/img/firefox/mobile/android.png) no-repeat;
+    background: 7px 20px url(/media/img/firefox/mobile/android.png) no-repeat;
 }
 
 a.more:after,