--levels=levels code Change the way that the levels on the map correspond to the zoom levels in the device. See customisation help. The default is: "0:24, 1:22, 2:20, 3:18, 4:16", although each style can have its own default. Up to 8 levels may be specified.
highway=unclassified [0x06 road_class=0 road_speed=3 resolution 21]
https://drive.google.com/drive/folders/1Cre9Q5T9Ubwl11eANFqPJF3qkPR2aiva