Allow disabling styling of fake nanoui windows

code/datums/browser.dm

@@ -28,6 +28,9 @@
 		height = nheight
 	if (nref)
 		ref = nref
+	// If a client exists, but they have disabled fancy windowing, disable it!
+	if(user && user.client && !user.client.is_preference_enabled(/datum/client_preference/browser_style))
+		return
 	add_stylesheet("common", 'html/browser/common.css') // this CSS sheet is common to all UIs
 
 /datum/browser/proc/set_title(ntitle)
@@ -178,4 +181,4 @@
 	if(src && src.mob)
 		//world << "[src] was [src.mob.machine], setting to null"
 		src.mob.unset_machine()
-	return
+	return