DevTools: make toolbar button click targets square

Source/devtools/front_end/inspectorStyle.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 140 matching lines @@
     display: none;
     position: absolute;
     left: 0;
     right: 0;
     height: 15px;
     z-index: -1;
 }
 
 .outline-disclosure li.selected .selection {
     display: block;
-    background-color: rgb(212, 212, 212);
+    background-color: #dadada;
 }
 
 .outline-disclosure li.in-clipboard .highlight {
     outline: 1px dotted darkgrey;
 }
 
 .outline-disclosure li.elements-drag-over .selection {
     display: block;
     margin-top: -2px;
     border-top: 2px solid rgb(56, 121, 217);
@@ skipping 104 matching lines @@
 }
 
 .child-editing {
     color: #222 !important;
     text-decoration: none !important;
     overflow: visible !important;
 }
 
 .sidebar {
     overflow-x: hidden;
-    background-color: #eee;
+    background-color: #f3f3f3;
 }
 
 .pane-title-button {
     color: rgb(6, 6, 6);
     background-color: transparent;
     border: 1px solid rgb(165, 165, 165);
     background-color: #eee;
     background-image: linear-gradient(to bottom, rgb(252, 252, 252), rgb(223, 223, 223));
     border-radius: 12px;
     -webkit-appearance: none;
@@ skipping 331 matching lines @@
 }
 
 body.inactive select.chrome-select,
 .chrome-select:disabled {
     background-image: -webkit-image-set(url(Images/chromeDisabledSelect.png) 1x, url(Images/chromeDisabledSelect_2x.png) 2x), linear-gradient(#f1f1f1, #f1f1f1 38%, #e6e6e6);
     border-color: rgba(80, 80, 80, 0.2);
     box-shadow: 0 1px 0 rgba(80, 80, 80, 0.08),
     inset 0 1px 2px rgba(255, 255, 255, 0.75);
     color: #aaa;
 }