Index: src/wp-includes/css/media-views.css
===================================================================
--- src/wp-includes/css/media-views.css	(revision 40141)
+++ src/wp-includes/css/media-views.css	(working copy)
@@ -183,19 +183,28 @@
 	right: 0;
 	width: 50px;
 	height: 50px;
+	margin: 0;
 	padding: 0;
+	border: 1px solid transparent;
+	background: none;
+	color: #666;
 	z-index: 1000;
+	cursor: pointer;
+	outline: none;
 	-webkit-transition: color .1s ease-in-out, background .1s ease-in-out;
 	transition: color .1s ease-in-out, background .1s ease-in-out;
 }
 
-.media-modal-close.button-link {
-	text-decoration: none;
+.media-modal-close:hover,
+.media-modal-close:active {
+	color: #00a0d2;
 }
 
-.media-modal-close:active {
-	-webkit-box-shadow: none;
-	box-shadow: none;
+.media-modal-close:focus {
+	color: #00a0d2;
+	border-color: #5b9dd9;
+	-webkit-box-shadow: 0 0 3px rgba( 0, 115, 170, .8 );
+	box-shadow: 0 0 3px rgba( 0, 115, 170, .8 );
 }
 
 .media-modal-close span.media-modal-icon {
@@ -209,17 +218,8 @@
 	vertical-align: middle;
 	-webkit-font-smoothing: antialiased;
 	-moz-osx-font-smoothing: grayscale;
-	color: #666;
 }
 
-.media-modal-close:hover .media-modal-icon:before {
-	color: #00a0d2;
-}
-
-.media-modal-close:active {
-	outline: 0;
-}
-
 .media-modal-content {
 	position: absolute;
 	top: 0;
Index: src/wp-includes/media-template.php
===================================================================
--- src/wp-includes/media-template.php	(revision 40141)
+++ src/wp-includes/media-template.php	(working copy)
@@ -163,7 +163,7 @@
 
 	<script type="text/html" id="tmpl-media-modal">
 		<div class="<?php echo $class; ?>">
-			<button type="button" class="button-link media-modal-close"><span class="media-modal-icon"><span class="screen-reader-text"><?php _e( 'Close media panel' ); ?></span></span></button>
+			<button type="button" class="media-modal-close"><span class="media-modal-icon"><span class="screen-reader-text"><?php _e( 'Close media panel' ); ?></span></span></button>
 			<div class="media-modal-content"></div>
 		</div>
 		<div class="media-modal-backdrop"></div>