Replace outdated colors with WikimediaUI palette ones

Replacing all colors with current WikimediaUI palette ones.
Also:
- changing two files over to LESS in order to
 - make use of central gradient mixin instead of one with
   unnecessary vendor extensions and
 - concatenating selectors in one occurrence.

Bug: T174237
Change-Id: I5d302f29b079f6abdba5abf3b58d6ba254e1a4ac

resources/css/ext.uls.interface.less

@@ -0,0 +1,22 @@
+/* stylelint-disable selector-no-id */
+@import 'mediawiki.mixins';
+
+#uls-settings-block {
+	border-top: 1px solid #c8ccd1;
+	.vertical-gradient( #fbfbfb, #f0f0f0 );
+	padding-left: 10px;
+	line-height: 1.2em;
+	border-radius: 0 0 5px 5px;
+}
+
+#uls-settings-block div.display-settings-block,
+#uls-settings-block div.input-settings-block {
+	display: inline-block;
+	margin: 8px 15px;
+	color: #54595d;
+}
+
+#uls-settings-block div.display-settings-block:hover,
+#uls-settings-block div.input-settings-block:hover {
+	color: #222;
+}