Hi there,
The gradient filter you’re currently applying is only valid for IE6 to IE9, please use linear gradient for IE10 and above.
Eg.
.x-navbar {
background: #999; /* for non-css3 browsers */
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr=’#4878af’, endColorstr=’#0f0f47′); /* for IE */
background: -webkit-gradient(linear, left top, left bottom, from(#4878af), to(#0f0f47)); /* for webkit browsers */
background: -moz-linear-gradient(top, #4878af, #0f0f47); /* for firefox 3.6+ */
background: linear-gradient(to bottom, #4878af 0%,#0f0f47 100%);
}
Cheers!