Dark Roadmap style.

gistfile1.js

var darkRoadmapStyle = [{
   featureType:"landscape.natural",
   stylers:[
      {
         gamma:0.01
      },
      {
         weight:0.1
      }
   ]
},
{
   stylers:[
      {
         saturation:-100
      },
      {
         invert_lightness:true
      },
      {
         gamma:4.17
      },
      {
         lightness:-87
      }
   ]
},
{
   elementType:"labels",
   stylers:[
      {
         visibility:"on"
      },
      {
         lightness:3
      },
      {
         gamma:1.85
      }
   ]
},
{
   stylers:[
      {
         weight:1.2
      }
   ]
},
{
   featureType:"road.highway",
   stylers:[
      {
         visibility:"simplified"
      },
      {
         weight:0.3
      }
   ]
},
{
   elementType:"labels.icon",
   stylers:[
      {
         visibility:"off"
      }
   ]
},
{
   featureType:"road.arterial",
   stylers:[
      {
         weight:0.3
      }
   ]
},
{
   featureType:"administrative.neighborhood",
   stylers:[
      {
         visibility:"off"
      }
   ]
},
{
   featureType:"administrative.locality",
   stylers:[
      {
         visibility:"off"
      }
   ]
},
{
   featureType:"poi",
   elementType:"labels",
   stylers:[
      {
         visibility:"off"
      }
   ]
},
{
   featureType:"poi",
   stylers:[
      {
         lightness:4
      }
   ]
},
{
   featureType:"administrative",
   stylers:[
      {
         lightness:14
      },
      {
         weight:0.8
      }
   ]
},
{
   featureType:"landscape.man_made",
   stylers:[
      {
         lightness:13
      }
   ]
},
{
   featureType:"road.local",
   stylers:[
      {
         weight:0.2
      }
   ]
},
{
   featureType:"road.highway",
   stylers:[
      {
         weight:0.3
      }
   ]
}]