Fixes issue where input icon might be reversed when font color of parent is reversed

src/elements/input.less

@@ -22,6 +22,8 @@
 .ui.input {
   display: inline-block;
   position: relative;
+
+  color: rgba(0, 0, 0, 0.7);
 }
 .ui.input input {
   width: 100%;