Add assets for focused dropbox teaser.

services/web/public/stylesheets/app/editor.less

@@ -400,4 +400,14 @@
 			background-color: @gray-lightest;
 		}
 	}
-}
+}
+
+.dropbox-teaser-title {
+	margin-top: 0;
+	text-align: center;
+}
+
+.dropbox-teaser-img {
+	.img-responsive;
+	margin-bottom: 5px;
+}