Index: src/wp-admin/credits.php
===================================================================
--- src/wp-admin/credits.php	(revision 35556)
+++ src/wp-admin/credits.php	(working copy)
@@ -25,13 +25,9 @@
 <div class="wp-badge"><?php printf( __( 'Version %s' ), $display_version ); ?></div>
 
 <h2 class="nav-tab-wrapper">
-	<a href="about.php" class="nav-tab">
-		<?php _e( 'What&#8217;s New' ); ?>
-	</a><a href="credits.php" class="nav-tab nav-tab-active">
-		<?php _e( 'Credits' ); ?>
-	</a><a href="freedoms.php" class="nav-tab">
-		<?php _e( 'Freedoms' ); ?>
-	</a>
+	<a href="about.php" class="nav-tab"><?php _e( 'What&#8217;s New' ); ?></a>
+	<a href="credits.php" class="nav-tab nav-tab-active"><?php _e( 'Credits' ); ?></a>
+	<a href="freedoms.php" class="nav-tab"><?php _e( 'Freedoms' ); ?></a>
 </h2>
 
 <?php
Index: src/wp-admin/css/about.css
===================================================================
--- src/wp-admin/css/about.css	(revision 35556)
+++ src/wp-admin/css/about.css	(working copy)
@@ -79,17 +79,8 @@
 
 /* Tabs */
 
-.about-wrap h2.nav-tab-wrapper {
-	padding-left: 6px;
-}
-
 .about-wrap h2 .nav-tab {
-	padding: 4px 15px 6px;
-	margin: 0 3px -1px 0;
 	font-size: 18px;
-	vertical-align: top;
-	border-width: 1px;
-	white-space: nowrap;
 }
 
 /* 1.1 - Typography */
@@ -429,17 +420,6 @@
 		width: 100%;
 	}
 
-	.about-wrap h2.nav-tab-wrapper {
-		padding-left: 0;
-		border-bottom: 0;
-	}
-
-	.about-wrap h2 .nav-tab {
-		margin-top: 10px;
-		margin-right: 10px;
-		border-bottom: 1px solid #ccc;
-	}
-
 	.about-wrap .feature-section .svg-container {
 		padding-top: 20px;
 		padding-bottom: 20px;
Index: src/wp-admin/css/common.css
===================================================================
--- src/wp-admin/css/common.css	(revision 35556)
+++ src/wp-admin/css/common.css	(working copy)
@@ -1997,20 +1997,25 @@
 ------------------------------------------------------------------------------*/
 
 .nav-tab {
+	display: inline-block;
 	border: 1px solid #ccc;
 	border-bottom: none;
+	margin: 0 5px 0 0;
+	padding: 6px 10px;
+	font-size: 15px;
+	line-height: 24px;
+	font-weight: 600;
 	background: #e4e4e4;
 	color: #555;
+	text-decoration: none;
+	white-space: nowrap;
 }
 
-.nav-tab,
+h3 .nav-tab, /* Back-compat for pre-4.4 */
 .nav-tab-small .nav-tab {
-	display: inline-block;
-	margin: -4px 4px -1px 0;
 	padding: 5px 14px;
 	font-size: 12px;
 	line-height: 16px;
-	text-decoration: none;
 }
 
 .nav-tab:hover,
@@ -2019,38 +2024,38 @@
 	color: #464646;
 }
 
+.nav-tab-active,
+.nav-tab:focus:active {
+	-webkit-box-shadow: none;
+	box-shadow: none;
+}
+
 .nav-tab-active {
+	margin-bottom: -1px;
 	color: #464646;
 }
 
 .nav-tab-active,
 .nav-tab-active:hover,
-.nav-tab-active:focus {
+.nav-tab-active:focus,
+.nav-tab-active:focus:active {
 	border-bottom: 1px solid #f1f1f1;
 	background: #f1f1f1;
 	color: #000;
 }
 
+/* @todo: consider to use flexbox to reset white space between inline-block elements. */
 h1.nav-tab-wrapper, /* Back-compat for pre-4.4 */
 .wrap h2.nav-tab-wrapper, /* higher specificity to override .wrap > h2:first-child */
 h3.nav-tab-wrapper {
 	border-bottom: 1px solid #ccc;
 	margin: 0;
-	padding: 9px 15px 0 10px;
-	font-size: 23px;
-	font-weight: 400;
-	line-height: 29px;
+	padding: 9px 15px 0 6px;
+	font-size: 1px; /* normalize white space between inline-block elements */
+	line-height: inherit;
 }
 
-h1 .nav-tab, /* Back-compat for pre-4.4 */
-h2 .nav-tab {
-	padding: 6px 10px;
-	font-weight: 600;
-	font-size: 15px;
-	line-height: 24px;
-}
 
-
 /*------------------------------------------------------------------------------
   26.0 - Misc
 ------------------------------------------------------------------------------*/
@@ -3597,6 +3602,21 @@
 	div#post-body.metabox-holder.columns-1 {
 		overflow-x: hidden;
 	}
+
+	h1.nav-tab-wrapper,
+	.wrap h2.nav-tab-wrapper,
+	h3.nav-tab-wrapper {
+		padding-left: 0;
+		border-bottom: 0;
+	}
+
+	h1 .nav-tab,
+	h2 .nav-tab,
+	h3 .nav-tab {
+		margin-top: 10px;
+		margin-right: 10px;
+		border-bottom: 1px solid #ccc;
+	}
 }
 
 @media screen and (max-width: 320px) {
Index: src/wp-admin/freedoms.php
===================================================================
--- src/wp-admin/freedoms.php	(revision 35556)
+++ src/wp-admin/freedoms.php	(working copy)
@@ -24,13 +24,9 @@
 <div class="wp-badge"><?php printf( __( 'Version %s' ), $display_version ); ?></div>
 
 <h2 class="nav-tab-wrapper">
-	<a href="about.php" class="nav-tab">
-		<?php _e( 'What&#8217;s New' ); ?>
-	</a><a href="credits.php" class="nav-tab">
-		<?php _e( 'Credits' ); ?>
-	</a><a href="freedoms.php" class="nav-tab nav-tab-active">
-		<?php _e( 'Freedoms' ); ?>
-	</a>
+	<a href="about.php" class="nav-tab"><?php _e( 'What&#8217;s New' ); ?></a>
+	<a href="credits.php" class="nav-tab"><?php _e( 'Credits' ); ?></a>
+	<a href="freedoms.php" class="nav-tab nav-tab-active"><?php _e( 'Freedoms' ); ?></a>
 </h2>
 
 <p class="about-description"><?php printf( __( 'WordPress is Free and open source software, built by a distributed community of mostly volunteer developers from around the world. WordPress comes with some awesome, worldview-changing rights courtesy of its <a href="%s">license</a>, the GPL.' ), 'https://wordpress.org/about/license/' ); ?></p>