Index: sites/trunk/wordpress.org/public_html/style/blog-wp4.css
===================================================================
--- sites/trunk/wordpress.org/public_html/style/blog-wp4.css	(revision 5554)
+++ sites/trunk/wordpress.org/public_html/style/blog-wp4.css	(working copy)
@@ -147,6 +147,7 @@
 .storycontent video {
 	max-width: 100%;
 	vertical-align: middle;
+	width: 100%;
 }
 
 /**
Index: sites/trunk/wordpress.org/public_html/style/wp4.css
===================================================================
--- sites/trunk/wordpress.org/public_html/style/wp4.css	(revision 5554)
+++ sites/trunk/wordpress.org/public_html/style/wp4.css	(working copy)
@@ -10,6 +10,14 @@
 a { text-decoration: none; }
 
 html {
+  box-sizing: border-box;
+}
+
+*, *:before, *:after {
+  box-sizing: inherit;
+}
+
+html {
 	overflow-y: scroll;
 }
 
@@ -2103,8 +2111,8 @@
 	body.wporg-responsive .col-8,
 	body.wporg-responsive .col-9,
 	body.wporg-responsive .col-10 {
-		margin-left: 14px;
-		margin-right: 14px;
+		margin: 0;
+		padding: 0 14px;
 	}
 
 	.wporg-responsive.wporg-page-parent-about .col-7,
@@ -2220,7 +2228,7 @@
 }
 
 
-/* 
+/*
  *  Notifications
  */