diff --git a/wp-includes/js/mediaelement/wp-mediaelement.css b/wp-includes/js/mediaelement/wp-mediaelement.css
index 2160abf93c..18ad94855b 100644
--- a/wp-includes/js/mediaelement/wp-mediaelement.css
+++ b/wp-includes/js/mediaelement/wp-mediaelement.css
@@ -8,4 +8,8 @@
 
 .mejs-controls .mejs-time-rail .mejs-time-current {
 	background: #d54e21;
-}
\ No newline at end of file
+}
+
+.me-cannotplay {
+	width: auto !important;
+}
diff --git a/wp-includes/media.php b/wp-includes/media.php
index d85f10e829..6111f36370 100644
--- a/wp-includes/media.php
+++ b/wp-includes/media.php
@@ -910,6 +910,7 @@ function wp_audio_shortcode( $attr ) {
 		'loop'     => $loop,
 		'autoplay' => $autoplay,
 		'preload'  => $preload,
+		'style'    => 'width: 100%',
 	);
 
 	// These ones should just be omitted altogether if they are blank