I remember earlier Google switched Doubleclick for Publishers to UI made with Dart and material design. It is awful and looks like a product of some low quality

I remember earlier Google switched Doubleclick for Publishers to UI made with Dart and material design. It is awful and looks like a product of some low quality outsourcing company. It is slow to load (needs to load about 10 Mb to start), it works very slowly, all animations are laggy. I checked with Developer Tools, didnt't see anything resembling Dart in Gmail (and it is not as slow as DFP). But there is 2.8 Mb JS file and 1.3 Mb CSS file (loaded 3 times, don't know why). I am not sure if this is really necessary to display a list of 20 newest emails. Also, a hangouts widget loads additional 600 kb of JS and 600 Kb of CSS.