#road_label[reflen>=1][reflen<=6]::shield {
  // Motorways with a 'ref' tag that is 1-6 characters long have a
  // [ref] value for shield-style labels.
  // Custom shield png files can be created using make_shields.sh
  // in _src folder
  shield-name: [ref];
  shield-face-name: @sans;
  shield-fill: #765;
  shield-min-distance: 60;
  shield-min-padding: 8;  // prevents clipped shields at tile edges
  shield-size: 9;
  shield-file: url('shield/motorway_sm_[reflen].png');
  [zoom>=15] {
    shield-size: 11;
    shield-file: url('shield/motorway_lg_[reflen].png');
  }
}

#road_label {
  text-name: @name;
  text-placement: line;  // text follows line path
  text-face-name: @sans;
  text-fill: #765;
  text-halo-fill: fadeout(#fff, 70%);
  text-halo-radius: 1;
  text-halo-rasterizer: fast;
  text-size: 12;
  text-avoid-edges: true;  // prevents clipped labels at tile edges
  [zoom>=15] { text-size: 13; }
}