DevTools: minor UI / menu tweaks reducing the clutter.

Source/devtools/front_end/elementsPanel.css

 /*
  * Copyright (C) 2006, 2007, 2008 Apple Inc.  All rights reserved.
  * Copyright (C) 2009 Anthony Ricaud <rik@webkit.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 17 matching lines @@
  */
 
 #elements-content {
     flex: 1 1;
     overflow: auto;
     padding-left: 0;
 }
 
 #elements-crumbs {
     flex: 0 0 19px;
-    background-color: rgb(236, 236, 236);
+    background-color: white;
     border-top: 1px solid #ccc;
     overflow: hidden;
 }
 
 #elements-content > ol {
     display: inline-block;
     min-height: 100%;
 }
 
 #elements-content .editing {
@@ skipping 636 matching lines @@
 
 .styles-clipboard-only {
     display: inline-block;
     width: 0;
     opacity: 0;
 }
 
 li.child-editing .styles-clipboard-only {
     display: none;
 }