<h1>Charles Hayter's Colour Diagrams</h1>
<div class="example-wrapper">
  <div class="grid1">
    <div class="grid__item yel1">
      <p>yellow</p>
    </div>
    <div class="grid__item yel2">
      <p>yellow</p>
    </div>
    <div class="grid__item red1">
      <p>red</p>
    </div>
    <div class="grid__item org1">
      <p>orange</p>
    </div>
    <div class="grid__item org2">
      <p>orange</p>
    </div>
    <div class="grid__item grn1">
      <p>green</p>
    </div>
    <div class="grid__item olv1">
      <p>olive</p>
    </div>

    <div class="grid__item red2">
      <p>red</p>
    </div>
    <div class="grid__item yel3">
      <p>yellow</p>
    </div>
    <div class="grid__item blu1">
      <p>blue</p>
    </div>
    <div class="grid__item grn2">
      <p>green</p>
    </div>
    <div class="grid__item org3">
      <p>orange</p>
    </div>
    <div class="grid__item prp1">
      <p>purple</p>
    </div>
    <div class="grid__item brn1">
      <p>brown</p>
    </div>

    <div class="grid__item blu2">
      <p>blue</p>
    </div>
    <div class="grid__item red3">
      <p>red</p>
    </div>
    <div class="grid__item blu3">
      <p>blue</p>
    </div>
    <div class="grid__item prp2">
      <p>purple</p>
    </div>
    <div class="grid__item grn3">
      <p>green</p>
    </div>
    <div class="grid__item prp3">
      <p>purple</p>
    </div>
    <div class="grid__item slt1">
      <p>slate</p>
    </div>
  </div>
  
  <div class="grid2">
    <div class="grid__item yel4">
      <p>yellow</p>
    </div>
    <div class="grid__item red4">
      <p>red</p>
    </div>
    <div class="grid__item blu4">
      <p>blue</p>
    </div>
    
    <div class="grid__item org4">
      <p>orange</p>
    </div>
    <div class="grid__item grn4">
      <p>green</p>
    </div>
    <div class="grid__item prp4">
      <p>purple</p>
    </div>
    
    <div class="grid__item olv2">
      <p>olive</p>
    </div>
    <div class="grid__item brn2">
      <p>brown</p>
    </div>
    <div class="grid__item slt2">
      <p>slate</p>
    </div>
  </div>
</div>

<div class="axioms">
  <h2>AXIOMS.</h2>
  <p><em>First</em>—That Yellow, Red, and Blue, are entire colours of themselves, and cannot be produced by the mixture of any other colours.–<em>See Plate I</em>.</p>
  <p><em>Secondly</em>—Yellow, Red, and Blue, contain the sole properties of producing all other colours whatsoever, as to colour, by mixtures arising entirely among themselves, without the aid of a fourth;–</p>
  <p><em>Thirdly</em>—Because, by mixing proper portions of the Three Primitives together, Black is obtained, providing for every possible degree of shadow.</p>
  <p><em>Fourthly</em>—And every practical degree of <em>light</em> is obtained by diluting any of the colours, as above producible ; or in oil-painting, by the mixture of white paint.</p>
  <p><em>Fifthly</em>—All transient or prismatic effects can be imitated with the Three Primitive Colours, as permanently considered, but only in the same degree of comparison as white bears to light.</p>
  <p><em>Sixthly</em>—There are no other materials, in which colour is found, that are possessed of any of the foregoing perfections.</p>
</div>

@import url('https://fonts.googleapis.com/css?family=Old+Standard+TT:400,400i');

$red: #c10909;
$orange: #e13e00;
$yellow: #e3ac00;
$green: #5e9077;
$olive: #83652d;
$blue: #3889b7;
$purple: #4f437d;
$brown: #752435;
$slate: #38416f;

html {
  box-sizing: border-box;
}

*,
*::before,
*::after {
  box-sizing: inherit;
}

body {
  background-image: radial-gradient(#e2d0b3, #e6ccaa);
  font-family: 'Old Standard TT', serif;
  padding: 0.5em;
}

// Responsive typography
$min-width: 320;
$max-width: 960;
$min-font: 18;
$max-font: 22;

:root {
  font-size: #{$min-font}px;
}

@media (min-width: #{$min-width}px) and (max-width: #{$max-width}px) {
  :root {
    font-size: calc( #{$min-font}px + (#{$max-font} - #{$min-font}) * ( (100vw - #{$min-width}px) / ( #{$max-width} - #{$min-width})));
  }
}

@media (min-width: #{$max-width}px) {
  :root {
    font-size: #{$max-font}px;
  }
}

h1 {
  text-align: center;
  font-size: 5vw;
  margin-bottom: 0.5em;
}

h2 {
  text-align: center;
  font-size: 3vw;
  margin-bottom: 0.5em;
}

p {
  line-height: 1.2;
  margin-bottom: 1em;
}

em {
  font-style: italic;
}

.example-wrapper::before {
  content: 'This example requires a browser that supports CSS Grid, like Firefox Nightly. If your browser did support CSS Grid, you would have seen something that resembled the image below, except recreated in HTML and CSS instead.';
  display: inline-block;
  margin-bottom: 1em;
  line-height: 1.2;
}

.example-wrapper::after {
  content: url('https://upload.wikimedia.org/wikipedia/commons/1/15/Color_diagram_Charles_Hayter.jpg');
  display: block;
  text-align: center;
}

.example-wrapper > * {
  display: none;
}

.example-wrapper {
  background: $red;
  padding: 5vmin;
  margin-bottom: 1em;
}

.axioms {
  max-width: 40em;
  margin: 0 auto;
}

@supports (display: grid) {
  .example-wrapper::before,
  .example-wrapper::after {
    content: none;
  }

  .example-wrapper {
    display: block;
    background-color: inherit;
    border: 0.2vw solid;
    
    p {
      font-style: italic;
      font-size: 1.5vw;
      margin: 0;
    }
  }
  
  .grid1 {
    display: grid;
    grid-template-columns: repeat(3, 2vw 5vw 5vw 5vw 5vw 5vw 2vw);
    grid-auto-rows: 15vw;
    grid-gap: 0.1vw;
    justify-content: center;

    margin-bottom: 1em;
  }

  .grid__item {
    border-radius: 50%;
    border: 0.1vw solid;
    box-shadow: 0px 0px 0px 0.4vw white, 0px 0px 0px 0.5vw black;

    display: flex;
    align-items: center;
    justify-content: center;
  }

  .yel1 {
    grid-row: 1;
    grid-column: 3 / span 3;
    background-color: $yellow;
  }

  .yel2 {
    grid-row: 2;
    grid-column: 2 / span 3;
    background-color: $yellow;
    mix-blend-mode: soft-light;
  }

  .red1 {
    grid-row: 2;
    grid-column: 4 / span 3;
    background-color: $red;
  }

  .org1 {
    grid-row: 3;
    grid-column: 3 / span 3;
    background-color: $orange;
  }

  .org2 {
    grid-row: 4;
    grid-column: 2 / span 3;
    background-color: $orange;
    mix-blend-mode: soft-light;
  }

  .grn1 {
    grid-row: 4;
    grid-column: 4 / span 3;
    background-color: $green;
  }

  .olv1 {
    grid-row: 5;
    grid-column: 3 / span 3;
    background-color: $olive;
  }

  .red2 {
    grid-row: 1;
    grid-column: 10 / span 3;
    background-color: $red;
  }

  .yel3 {
    grid-row: 2;
    grid-column: 9 / span 3;
    background-color: $yellow;
    mix-blend-mode: soft-light;
  }

  .blu1 {
    grid-row: 2;
    grid-column: 11 / span 3;
    background-color: $blue;
  }

  .grn2 {
    grid-row: 3;
    grid-column: 10 / span 3;
    background-color: $green;
  }

  .org3 {
    grid-row: 4;
    grid-column: 9 / span 3;
    background-color: $orange;
    mix-blend-mode: soft-light;
  }

  .prp1 {
    grid-row: 4;
    grid-column: 11 / span 3;
    background-color: $purple;
  }

  .brn1 {
    grid-row: 5;
    grid-column: 10 / span 3;
    background-color: $brown;
  }

  .blu2 {
    grid-row: 1;
    grid-column: 17 / span 3;
    background-color: $blue;
  }

  .red3 {
    grid-row: 2;
    grid-column: 16 / span 3;
    background-color: $red;
    mix-blend-mode: soft-light;
  }

  .blu3 {
    grid-row: 2;
    grid-column: 18 / span 3;
    background-color: $blue;
  }

  .prp2 {
    grid-row: 3;
    grid-column: 17 / span 3;
    background-color: $purple;
  }

  .grn3 {
    grid-row: 4;
    grid-column: 16 / span 3;
    background-color: $green;
    mix-blend-mode: soft-light;
  }

  .prp3 {
    grid-row: 4;
    grid-column: 18 / span 3;
    background-color: $purple;
  }

  .slt1 {
    grid-row: 5;
    grid-column: 17 / span 3;
    background-color: $slate;
  }
  
  .grid2 {
    display: grid;
    grid-template-columns: repeat(3, 0.5vw 6vw 6vw 6vw 6vw 6vw 0.5vw);
    grid-auto-rows: 9vw;
    grid-gap: 0.1vw;
    justify-content: center;
  }

  .yel4 {
    grid-row: 1 / span 2;
    grid-column: 2 / span 3;
    background-color: $yellow;
    mix-blend-mode: soft-light;
  }

  .red4 {
    grid-row: 1 / span 2;
    grid-column: 4 / span 3;
    background-color: $red;
    mix-blend-mode: soft-light;
  }

  .blu4 {
    grid-row: 2 / span 2;
    grid-column: 3 / span 3;
    background-color: $blue;
  }

  .org4 {
    grid-row: 1 / span 2;
    grid-column: 10 / span 3;
    background-color: $orange;
    mix-blend-mode: soft-light;
  }

  .grn4 {
    grid-row: 2 / span 2;
    grid-column: 9 / span 3;
    background-color: $green;
  }

  .prp4 {
    grid-row: 2 / span 2;
    grid-column: 11 / span 3;
    background-color: $purple;
    mix-blend-mode: soft-light;
  }

  .olv2 {
    grid-row: 1 / span 2;
    grid-column: 16 / span 3;
    background-color: $olive;
    mix-blend-mode: soft-light;
  }

  .brn2 {
    grid-row: 1 / span 2;
    grid-column: 18 / span 3;
    background-color: $brown;
    mix-blend-mode: soft-light;
  }

  .slt2 {
    grid-row: 2 / span 2;
    grid-column: 17 / span 3;
    background-color: $slate;
  }
}

/*
An attempt to recreate the colour diagrams in Charles Hayter's “A New Practical Treatise on the Three Primitive Colours Assumed as a Perfect System of Rudimentary Information”. Original text available at https://archive.org/details/newpracticaltrea00hayt.
*/