Color contrast: have skip links use a black color rather than navy (#10583)

* have skip links use a black color rather than navy

* keep the text color of the skip links constant

Author: srietkerk

docfiles/style.css

@@ -185,7 +185,7 @@ svg {
     line-height: 4em;
     font-size: 1em;
     text-align: center;
-    color: #387894;
+    color: black;
     background: hsla(0,0%,100%,.9)!important;
 }
 

theme/accessibility.less

@@ -11,7 +11,7 @@
 *******************************/
 
 @accessibleMenuBackground: rgba(255,255,255,.9);
-@accessibleMenuColor: #387894;
+@accessibleMenuColor: black;
 
 /* Main menu focus */
 #mainmenu .ui.item:focus {