gistfile1.txt

#world[zoom >= 14] {
  a/line-width: 5;
  a/line-color: blue;
  [highway = 'primary'] {
    a/line-color: red;
  }
  b/line-width: 15;
  b/line-dasharray: 5,15;
  [zoom >= 15] {
    a/line-width: 8;
    b/line-width: 16;
  }
}