diff --git a/src/wp-admin/css/common.css b/src/wp-admin/css/common.css
index 5f9022ebf5..21e9d7ed71 100644
--- a/src/wp-admin/css/common.css
+++ b/src/wp-admin/css/common.css
@@ -3026,11 +3026,12 @@ div.action-links {
 	left: auto;
 	right: -30px;
 	color: #f0f0f1;
+	border: 1px solid #fff;
 }
 
 .plugin-details-modal #TB_closeWindowButton:hover,
 .plugin-details-modal #TB_closeWindowButton:focus {
-	color: #135e96;
+	color: #fff;
 	outline: none;
 	box-shadow: none;
 }
@@ -3047,6 +3048,10 @@ div.action-links {
 	-moz-osx-font-smoothing: grayscale;
 }
 
+.plugin-details-modal #TB_closeWindowButton:after{
+	font-size: 26px;
+}
+
 /* move plugin install close icon to top on narrow screens */
 @media screen and (max-width: 830px) {
 	.plugin-details-modal #TB_closeWindowButton {