Revert vertical gradient spec to 'to bottom' as 'top' doesn't work in IE10

less/mixins.less

@@ -425,7 +425,7 @@
     background-image: -webkit-gradient(linear, 0 0, 0 100%, from(@startColor), to(@endColor)); // Safari 4+, Chrome 2+
     background-image: -webkit-linear-gradient(top, @startColor, @endColor); // Safari 5.1+, Chrome 10+
     background-image: -o-linear-gradient(top, @startColor, @endColor); // Opera 11.10
-    background-image: linear-gradient(top, @startColor, @endColor); // Standard, IE10
+    background-image: linear-gradient(to bottom, @startColor, @endColor); // Standard, IE10
     background-repeat: repeat-x;
     filter: e(%("progid:DXImageTransform.Microsoft.gradient(startColorstr='%d', endColorstr='%d', GradientType=0)",argb(@startColor),argb(@endColor))); // IE9 and down
   }