{
  "version": 1,
  "group": "contrast",
  "description": "Known WCAG 2.x relative-luminance contrast vectors. Threshold decisions use rawRatio; displayRatio is presentation-only rounding.",
  "thresholds": {
    "normalAA": 4.5,
    "normalAAA": 7,
    "largeAA": 3,
    "largeAAA": 4.5,
    "uiAA": 3
  },
  "cases": [
    {
      "id": "black-on-white",
      "foreground": "#000000",
      "background": "#FFFFFF",
      "expected": { "rawRatio": 21, "displayRatio": 21, "normalAA": true, "normalAAA": true, "largeAA": true, "largeAAA": true, "uiAA": true },
      "symmetric": true
    },
    {
      "id": "white-on-black",
      "foreground": "#FFFFFF",
      "background": "#000000",
      "expected": { "rawRatio": 21, "displayRatio": 21, "normalAA": true, "normalAAA": true, "largeAA": true, "largeAAA": true, "uiAA": true },
      "symmetric": true
    },
    {
      "id": "same-color",
      "foreground": "#336699",
      "background": "#336699",
      "expected": { "rawRatio": 1, "displayRatio": 1, "normalAA": false, "normalAAA": false, "largeAA": false, "largeAAA": false, "uiAA": false },
      "symmetric": true
    },
    {
      "id": "777-on-white-just-fails-aa-normal",
      "foreground": "#777777",
      "background": "#FFFFFF",
      "expected": { "rawRatio": 4.478089453577214, "displayRatio": 4.48, "normalAA": false, "normalAAA": false, "largeAA": true, "largeAAA": false, "uiAA": true },
      "symmetric": true
    },
    {
      "id": "767676-on-white-passes-aa-normal",
      "foreground": "#767676",
      "background": "#FFFFFF",
      "expected": { "rawRatio": 4.542224959605253, "displayRatio": 4.54, "normalAA": true, "normalAAA": false, "largeAA": true, "largeAAA": true, "uiAA": true },
      "symmetric": true
    },
    {
      "id": "595959-on-white-passes-aaa-normal",
      "foreground": "#595959",
      "background": "#FFFFFF",
      "expected": { "rawRatio": 7.004729208035935, "displayRatio": 7, "normalAA": true, "normalAAA": true, "largeAA": true, "largeAAA": true, "uiAA": true },
      "symmetric": true
    },
    {
      "id": "5a5a5a-on-white-fails-aaa-normal",
      "foreground": "#5A5A5A",
      "background": "#FFFFFF",
      "expected": { "rawRatio": 6.896926215312931, "displayRatio": 6.9, "normalAA": true, "normalAAA": false, "largeAA": true, "largeAAA": true, "uiAA": true },
      "symmetric": true
    },
    {
      "id": "rounded-display-must-not-pass-aa",
      "foreground": "#070707",
      "background": "#777777",
      "expected": { "rawRatio": 4.4983480864214345, "displayRatio": 4.5, "normalAA": false, "normalAAA": false, "largeAA": true, "largeAAA": false, "uiAA": true },
      "symmetric": true,
      "regression": "A displayed 4.50 must not pass when the unrounded internal ratio is below 4.5."
    }
  ]
}