Index: wp-admin/css/wp-admin.dev.css
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- wp-admin/css/wp-admin.dev.css	(revision 21437)
+++ wp-admin/css/wp-admin.dev.css	(revision )
@@ -1041,10 +1041,9 @@
 	padding-left: 5px;
 }
 
-
-/*------------------------------------------------------------------------------
-  4.0 - Notifications
-------------------------------------------------------------------------------*/
+	/*------------------------------------------------------------------------------
+	 4.0 - Notifications
+ ------------------------------------------------------------------------------*/
 
 #update-nag,
 .update-nag {
@@ -2343,6 +2342,20 @@
 }
 
 
+/**
+ * HiDPI graphics
+ */
+@media
+only screen and (-webkit-min-device-pixel-ratio: 1.5),
+only screen and (min-resolution: 150dpi) {
+
+	.welcome-panel .welcome-panel-close:before {
+		background-image: url("../images/xit-2x.gif");
+		background-size: 20px auto;
+	}
+
+}
+
 /*------------------------------------------------------------------------------
   10.0 - List Posts (/Pages/etc)
 ------------------------------------------------------------------------------*/
@@ -4192,7 +4205,10 @@
 	padding: 2px 10px;
 }
 
-@media only screen and (-webkit-min-device-pixel-ratio: 1.5) {
+@media
+only screen and (-webkit-min-device-pixel-ratio: 1.5),
+only screen and (min-resolution: 150dpi) {
+
 	.imgedit-crop,
 	.imgedit-rleft,
 	.imgedit-rright,
@@ -4200,11 +4216,17 @@
 	.imgedit-fliph,
 	.imgedit-undo,
 	.imgedit-redo {
-		background-image: url('../images/imgedit-icons-2x.png');
+		background-image: url("../images/imgedit-icons-2x.png");
 		background-size: 260px 64px;
 	}
+
+	.imgedit-wait {
+		background-image: url("../images/wpspin_light-2x.gif");
+		background-size: 16px 16px;
-}
+	}
 
+}
+
 /*------------------------------------------------------------------------------
   15.0 - Comments Screen
 ------------------------------------------------------------------------------*/
@@ -5450,6 +5472,17 @@
 	transition-duration:         0.2s;
 }
 
+@media
+only screen and (-webkit-min-device-pixel-ratio: 1.5),
+only screen and (min-resolution: 150dpi) {
+
+	.wp-full-overlay .collapse-sidebar-arrow {
+		background-image: url("../images/arrows-2x.png");
+		background-size: 15px 123px;
+	}
+
+}
+
 /*------------------------------------------------------------------------------
   24.0 - Customize Loader
 ------------------------------------------------------------------------------*/
@@ -5559,6 +5592,17 @@
 	line-height: 20px;
 }
 
+@media
+only screen and (-webkit-min-device-pixel-ratio: 1.5),
+only screen and (min-resolution: 150dpi) {
+
+	.customize-loading #customize-container {
+		background-image: url("../images/wpspin_light.gif");
+		background-size: 16px 16px;
+	}
+
+}
+
 /*------------------------------------------------------------------------------
   25.0 - Misc
 ------------------------------------------------------------------------------*/
@@ -8160,6 +8204,29 @@
 		max-width: 400px;
 		width: auto;
 	}
+}
+
+@media
+only screen and (-webkit-min-device-pixel-ratio: 1.5),
+only screen and (min-resolution: 150dpi) {
+
+	.press-this .tagchecklist span a {
+		background-image: url("../images/xit-2x.gif");
+		background-size: 20px auto;
+	}
+
+	.postbox:hover .handlediv,
+	.stuffbox:hover .handlediv,
+	.widget-top a.widget-action {
+		background-image: url("../images/arrows-2x.png");
+		background-size: 15px 123px;
+	}
+
+	.widget-top a.widget-action:hover {
+		background-image: url("../images/arrows-dark-2x.png");
+		background-size: 15px 123px;
+	}
+
 }
 
 /* =Localized CSS