/*
  cpt-city: jmn/jmn-d20 (cpt)

  A colourmap with monotonic luminance for simultaneous colour and
  grey-scale publications.

  J. McNames, "An effective color scale for simultaneous color and
  gray-scale publications," in IEEE Signal Processing Magazine,
  vol. 23, no. 1, pp. 82-96, Jan. 2006,

  author: James McNames
  copyright: Free to use
  year: 2009
  url: https://phillips.shef.ac.uk/pub/cpt-city/jmn
*/
linear-gradient(
  0deg,
  rgb(255, 255, 255)   0.000%,
  rgb(255, 255, 255)   5.000%,
  rgb(244, 228, 251)   5.000%,
  rgb(244, 228, 251)  10.000%,
  rgb(224, 207, 252)  10.000%,
  rgb(224, 207, 252)  15.000%,
  rgb(196, 192, 254)  15.000%,
  rgb(196, 192, 254)  20.000%,
  rgb(162, 188, 252)  20.000%,
  rgb(162, 188, 252)  25.000%,
  rgb(127, 193, 242)  25.000%,
  rgb(127, 193, 242)  30.000%,
  rgb( 94, 206, 221)  30.000%,
  rgb( 94, 206, 221)  35.000%,
  rgb( 69, 224, 188)  35.000%,
  rgb( 69, 224, 188)  40.000%,
  rgb( 56, 241, 144)  40.000%,
  rgb( 56, 241, 144)  45.000%,
  rgb( 59, 250,  92)  45.000%,
  rgb( 59, 250,  92)  50.000%,
  rgb( 79, 237,  45)  50.000%,
  rgb( 79, 237,  45)  55.000%,
  rgb(104, 200,  16)  55.000%,
  rgb(104, 200,  16)  60.000%,
  rgb(121, 157,   2)  60.000%,
  rgb(121, 157,   2)  65.000%,
  rgb(127, 112,   0)  65.000%,
  rgb(127, 112,   0)  70.000%,
  rgb(122,  72,   6)  70.000%,
  rgb(122,  72,   6)  75.000%,
  rgb(105,  40,  15)  75.000%,
  rgb(105,  40,  15)  80.000%,
  rgb( 80,  18,  22)  80.000%,
  rgb( 80,  18,  22)  85.000%,
  rgb( 51,   5,  23)  85.000%,
  rgb( 51,   5,  23)  90.000%,
  rgb( 23,   0,  15)  90.000%,
  rgb( 23,   0,  15)  95.000%,
  rgb(  0,   0,   0)  95.000%,
  rgb(  0,   0,   0) 100.000%
);