AAA compliant scrollbars hc-dark

src/vs/base/browser/ui/scrollbar/media/scrollbars.css

@@ -90,13 +90,13 @@
 .hc-black .monaco-scrollable-element > .scrollbar > .slider {
 	background: none;
 	border: 20px solid #6FC3DF;
-	opacity: .3;
+	opacity: .4;
 }
 
 .hc-black .monaco-scrollable-element > .scrollbar > .slider:hover {
-	opacity: .35;
+	opacity: .85;
 }
 
 .hc-black .monaco-scrollable-element > .scrollbar > .slider.active {
-	opacity: .4;
+	opacity: .9;
 }
\ No newline at end of file

src/vs/editor/css/hc-black-theme.css

@@ -141,7 +141,7 @@
 .monaco-editor.hc-black .snippet-placeholder		{ background-color: rgba(124, 124, 124, 0.1); }
 .monaco-editor.hc-black .finish-snippet-placeholder	{ outline: #525252 solid 1px; }
 
-/* Scrollbar */
+/* Scrollbar */    /* TODO: many of these are not doing anything, not specific enough.  Clean up */
 .hc-black.monaco-scrollable-element .slider {
 	background: none;
 	border: 20px solid #6FC3DF;