Update css.php for Operator Panel (#5382)

Add new CSS class for non-registered extensions. Button will appear disabled on the operator panel.

themes/default/css.php

@@ -1950,6 +1950,40 @@ header('Expires: '.gmdate('D, d M Y H:i:s',time()+3600).' GMT');
 		cursor: default;
 		}
 
+	div.off_ext {
+		position: relative;
+		float: left;
+		width: 235px;
+		margin: 0px 8px 8px 0px;
+		padding: 0px;
+		border-style: solid;
+		-moz-border-radius: 5px;
+		-webkit-border-radius: 5px;
+		border-radius: 5px;
+		-webkit-box-shadow: 0 0 3px #e5e9f0;
+		-moz-box-shadow: 0 0 3px #e5e9f0;
+		box-shadow: 0 0 3px #e5e9f0;
+		border-width: 1px 3px;
+		border-color: #b9c5d8 #c5d1e5;
+		background-color: #e5eaf5;
+		cursor: not-allowed;
+		}
+		
+		div.off_ext:after {
+			position: absolute;
+			content: "";
+			z-index: 10;
+			-moz-border-radius: 5px;
+			-webkit-border-radius: 5px;
+			border-radius: 5px;
+			display: block;
+			height: 100%;
+			top: 0;
+			left: 0;
+			right: 0;
+			background: rgba(255, 255, 255, 0.5);
+		}
+
 	div.op_state_active {
 		background-color: #baf4bb;
 		border-width: 1px 3px;
@@ -1962,7 +1996,7 @@ header('Expires: '.gmdate('D, d M Y H:i:s',time()+3600).' GMT');
 		border-color: #41b9eb;
 		}
 
-	table.op_ext {
+	table.op_ext, table.off_ext {
 		width: 100%;
 		height: 70px;
 		-moz-border-radius: 5px;