chrome/browser/resources/options/subpages_tab_controls.css

/* Copyright (c) 2012 The Chromium Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file. */

.subpages-nav-tabs .tab {
  padding: 4px 8px;
  position: relative;
}

.subpages-nav-tabs .active-tab {
  -webkit-box-shadow: 8px -8px 12px -6px rgb(240, 240, 240);
  background: white;
  border: 1px solid #ddd;
  border-bottom: 2px solid white;
  border-top-left-radius: 3px;
  border-top-right-radius: 3px;
  position: relative;
}

/* To avoid tabs changing size when they are clicked and their labels become
 * bold, we actually put two labels inside each tab: an inactive label and an
 * active label. Only one is visible at a time, but the bold label is used to
 * size the tab even when it's not visible. This keeps the tab size constant.
 */
.subpages-nav-tabs .active-tab-label,
.subpages-nav-tabs .tab-label:hover {
  font-weight: bold;
}

.subpages-nav-tabs .tab-label {
  left: 9px;
  position: absolute;
  top: 5px;
}

html[dir=rtl] .subpages-nav-tabs .tab-label {
  right: 9px;
}

.subpages-nav-tabs .active-tab-label,
.subpages-nav-tabs .active-tab .tab-label {
  visibility: hidden;
}

/* .tab is not removed when .active-tab is added, so we must
 * override the hidden visibility above in the active tab case.
 */
.subpages-nav-tabs .active-tab .active-tab-label {
  visibility: visible;
}

.subpages-nav-tabs {
  background-image: -webkit-gradient(
                        linear,
                        left top,
                        left bottom,
                        color-stop(0, rgb(255,255,255)),
                        color-stop(0.6, rgb(255,255,255)),
                        color-stop(0.8, rgb(250, 250, 250)),
                        color-stop(1.0, rgb(242,242,242))
  );
  border-bottom: 1px solid #ddd;
  padding: 4px 20px;
}

.subpages-tab-contents {
   -webkit-padding-start: 10px;
  display: none;
  padding-top: 15px;
}

.active-tab-contents {
  display: block;
}