Index: src/wp-admin/css/theme.css
===================================================================
--- src/wp-admin/css/theme.css	(revision 26329)
+++ src/wp-admin/css/theme.css	(working copy)
@@ -529,6 +529,7 @@
 	float: left;
 	margin: 0 30px 0 0;
 	width: 55%;
+	max-width: 900px;
 	text-align: center;
 }
 /* First screenshot, shown big */
@@ -744,7 +745,19 @@
  * Shuffles theme columns around based on screen width
  */
 
-@media ( min-width: 1700px ) {
+@media ( min-width: 2000px ) {
+	.theme-browser .theme {
+		width: 17.6%;
+	}
+	.theme-browser .theme:nth-child(3n),
+	.theme-browser .theme:nth-child(4n) {
+		margin-right: 3%;
+	}
+	.theme-browser .theme:nth-child(5n) {
+		margin-right: 0;
+	}
+}
+@media ( min-width: 1600px ) {
 	.theme {
 		width: 22.7%;
 		margin: 0 3% 3% 0;
@@ -761,7 +774,7 @@
 		left: 22%;
 	}
 }
-@media ( max-width: 1200px ) {
+@media ( max-width: 1150px ) {
 	.theme {
 		width: 47.5%;
 		margin-right: 0;
@@ -812,18 +825,20 @@
 		top: 3px;
 	}
 }
-@media ( max-width: 650px ) {
+@media ( max-width: 480px ) {
 	.theme {
 		width: 100%;
 		margin-right: 0;
 	}
-	.theme:hover .theme-actions {
-		display: none;
-	}
 	.theme:nth-child(2n),
 	.theme:nth-child(3n) {
 		margin-right: 0;
 	}
+}
+@media ( max-width: 650px ) {
+	.theme:hover .theme-actions {
+		display: none;
+	}
 	.theme-overlay .theme-update,
 	.theme-overlay .theme-description {
 		margin-left: 0;