To get rid of "Mixed content" warnings I'm trying to access stamen map tiles via https. For http the used url is:
http://{s}.sm.mapstack.stamen.com/(toner-lite,$fff[difference],$fff[@23],$fff[hsl-saturation@20])/{z}/{x}/{y}.png
It's working fine with leaflet. After reading the notes on maps.stamen.com the protcol independet endpoint is http(s)://stamen-tiles-{s}.a.ssl.fastly.net/
I replaced the url by https://stamen-tiles-{s}.a.ssl.fastly.net/(toner-lite,$fff[difference],$fff[@23],$fff[hsl-saturation@20])/{z}/{x}/{y}.png
But this solution won't work. I got only file not found errors
After poking around https://stamen-tiles-{s}.a.ssl.fastly.net/toner-lite/{z}/{x}/{y}.png
succeded but isn't the wanted sytle.
Any ideas how to solve this problem?