How can we remove the rainbow effect on the slider images?

.overlay.color {
opacity: 0.5;
/* background: #00f6ff
; */
background: url(data:image/svg+xml;
base64, PD94bWwgdmVyc2lvbj0iMS4wIiA/Pgo8c3ZnIHhtbG…EiIGhlaWdodD0iMSIgZmlsbD0idXJsKCNncmFkLXVjZ2ctZ2VuZXJhdGVkKSIgLz4KPC9zdmc+);
background: -moz-linear-gradient(left, #00f6ff
0%, #007eff
25%, #7814ff
50%, #86297a
75%, #ff6600
100%);
/* background: -webkit-gradient(linear, left top, right top, color-stop(0%, #00f6ff
), color-stop(25%, #007eff
), color-stop(50%, #7814ff
), color-stop(75%, #86297a
), color-stop(100%, #ff6600
)); */
/* background: -webkit-linear-gradient(left, #00f6ff
0%, #007eff
25%, #7814ff
50%, #86297a
75%, #ff6600
100%); */
background: -o-linear-gradient(left, #00f6ff
0%, #007eff
25%, #7814ff
50%, #86297a
75%, #ff6600
100%);
background: -ms-linear-gradient(left, #00f6ff
0%, #007eff
25%, #7814ff
50%, #86297a
75%, #ff6600
100%);
/* background: linear-gradient(to right, #00f6ff
0%, #007eff
25%, #7814ff
50%, #86297a
75%, #ff6600
100%); */
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#00f6ff
', endColorstr='#ff6600
', GradientType=1);
}
​

.overlay.color {
background-color: rgba(0,0,0,0.6);
}