To Do in Web Browser - Themes

I just switched from Wunderlist.  Why can't I change my theme in to do? to an actual background like in wunderlist.com.    I only use the web browser and I don't want to download the to do app.  It seems like to do web browser is an after thought with the visual appearances compared to the to do app.  Wunderlist web browser was so visually appealing.  Will this change?