As most of these apps doesn't have support for custom CSS you can get around that by using [subfilter](http://nginx.org/en/docs/http/ngx_http_sub_module.html) in Nginx or a browser addon called Stylus.
As most of these apps doesn't have support for custom CSS you can get around that by using [subfilter](http://nginx.org/en/docs/http/ngx_http_sub_module.html) in Nginx or a browser addon called Stylus.