{
  "version": "color-validation-v1",
  "updated": "2026-09-14",
  "page": "https://color-match.io/validation",
  "description": "28 independently calculated WCAG references, 6 attributed CIEDE2000 references, and 6 explicitly labelled correction invariants. These are implementation checks, not site accessibility certification.",
  "referenceCalculation": "Python Decimal at 50-digit precision; scripts/reference/contrast-reference.py; stored expected values are not regenerated by the build.",
  "differenceMethod": {
    "version": "ciede2000-srgb-d50-v1",
    "name": "CIEDE2000 (ΔE00)",
    "colorSpace": "Opaque 8-bit sRGB → CIE XYZ → CIE Lab",
    "whitePoint": "D50",
    "observer": "CIE 1931 2°",
    "adaptation": "Bradford D65 → D50",
    "parameters": {
      "kL": 1,
      "kC": 1,
      "kH": 1
    },
    "sources": [
      "https://www.w3.org/TR/css-color-4/#color-conversion-code",
      "https://hajim.rochester.edu/ece/sites/gsharma/ciede2000/"
    ]
  },
  "attribution": "Color Match-authored notes and contrast inputs: CC BY 4.0. CIEDE2000 reference values: Sharma, Wu & Dalal (2005), Table 1; original implementation code is not included.",
  "sources": {
    "contrast": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
    "difference": "https://hajim.rochester.edu/ece/sites/gsharma/ciede2000/",
    "conversion": "https://www.w3.org/TR/css-color-4/#color-conversion-code"
  },
  "cases": [
    {
      "id": "contrast-01",
      "kind": "contrast-reference",
      "label": "Black on white maximum",
      "inputs": "#000000 on #FFFFFF",
      "expected": "21",
      "expectedValue": 21,
      "expectedPass": true,
      "actual": 21,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=000000&bg=FFFFFF&target=4.5",
      "foreground": "#000000",
      "background": "#FFFFFF",
      "target": 4.5
    },
    {
      "id": "contrast-02",
      "kind": "contrast-reference",
      "label": "Reversed maximum",
      "inputs": "#FFFFFF on #000000",
      "expected": "21",
      "expectedValue": 21,
      "expectedPass": true,
      "actual": 21,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=FFFFFF&bg=000000&target=4.5",
      "foreground": "#FFFFFF",
      "background": "#000000",
      "target": 4.5
    },
    {
      "id": "contrast-03",
      "kind": "contrast-reference",
      "label": "Identical black",
      "inputs": "#000000 on #000000",
      "expected": "1",
      "expectedValue": 1,
      "expectedPass": false,
      "actual": 1,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=000000&bg=000000&target=4.5",
      "foreground": "#000000",
      "background": "#000000",
      "target": 4.5
    },
    {
      "id": "contrast-04",
      "kind": "contrast-reference",
      "label": "Identical gray",
      "inputs": "#808080 on #808080",
      "expected": "1",
      "expectedValue": 1,
      "expectedPass": false,
      "actual": 1,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=808080&bg=808080&target=4.5",
      "foreground": "#808080",
      "background": "#808080",
      "target": 4.5
    },
    {
      "id": "contrast-05",
      "kind": "contrast-reference",
      "label": "Identical white",
      "inputs": "#FFFFFF on #FFFFFF",
      "expected": "1",
      "expectedValue": 1,
      "expectedPass": false,
      "actual": 1,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=FFFFFF&bg=FFFFFF&target=4.5",
      "foreground": "#FFFFFF",
      "background": "#FFFFFF",
      "target": 4.5
    },
    {
      "id": "contrast-06",
      "kind": "contrast-reference",
      "label": "Just below normal-text AA",
      "inputs": "#777777 on #FFFFFF",
      "expected": "4.4780894535772156",
      "expectedValue": 4.4780894535772156,
      "expectedPass": false,
      "actual": 4.478089453577214,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=777777&bg=FFFFFF&target=4.5",
      "foreground": "#777777",
      "background": "#FFFFFF",
      "target": 4.5
    },
    {
      "id": "contrast-07",
      "kind": "contrast-reference",
      "label": "Just above normal-text AA",
      "inputs": "#767676 on #FFFFFF",
      "expected": "4.542224959605254",
      "expectedValue": 4.542224959605254,
      "expectedPass": true,
      "actual": 4.542224959605253,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=767676&bg=FFFFFF&target=4.5",
      "foreground": "#767676",
      "background": "#FFFFFF",
      "target": 4.5
    },
    {
      "id": "contrast-08",
      "kind": "contrast-reference",
      "label": "Above normal-text AAA",
      "inputs": "#595959 on #FFFFFF",
      "expected": "7.004729208035935",
      "expectedValue": 7.004729208035935,
      "expectedPass": true,
      "actual": 7.004729208035935,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=595959&bg=FFFFFF&target=7",
      "foreground": "#595959",
      "background": "#FFFFFF",
      "target": 7
    },
    {
      "id": "contrast-09",
      "kind": "contrast-reference",
      "label": "Below normal-text AAA",
      "inputs": "#5A5A5A on #FFFFFF",
      "expected": "6.8969262153129325",
      "expectedValue": 6.8969262153129325,
      "expectedPass": false,
      "actual": 6.896926215312931,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=5A5A5A&bg=FFFFFF&target=7",
      "foreground": "#5A5A5A",
      "background": "#FFFFFF",
      "target": 7
    },
    {
      "id": "contrast-10",
      "kind": "contrast-reference",
      "label": "Above the 3:1 boundary",
      "inputs": "#949494 on #FFFFFF",
      "expected": "3.033469825738476",
      "expectedValue": 3.033469825738476,
      "expectedPass": true,
      "actual": 3.0334698257384747,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=949494&bg=FFFFFF&target=3",
      "foreground": "#949494",
      "background": "#FFFFFF",
      "target": 3
    },
    {
      "id": "contrast-11",
      "kind": "contrast-reference",
      "label": "Below the 3:1 boundary",
      "inputs": "#959595 on #FFFFFF",
      "expected": "2.995346135708812",
      "expectedValue": 2.995346135708812,
      "expectedPass": false,
      "actual": 2.9953461357088114,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=959595&bg=FFFFFF&target=3",
      "foreground": "#959595",
      "background": "#FFFFFF",
      "target": 3
    },
    {
      "id": "contrast-12",
      "kind": "contrast-reference",
      "label": "CSS teal and white",
      "inputs": "#008080 on #FFFFFF",
      "expected": "4.77340948429513",
      "expectedValue": 4.77340948429513,
      "expectedPass": true,
      "actual": 4.7734094842951285,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=008080&bg=FFFFFF&target=4.5",
      "foreground": "#008080",
      "background": "#FFFFFF",
      "target": 4.5
    },
    {
      "id": "contrast-13",
      "kind": "contrast-reference",
      "label": "CSS turquoise and white",
      "inputs": "#40E0D0 on #FFFFFF",
      "expected": "1.6417700249072609",
      "expectedValue": 1.6417700249072609,
      "expectedPass": false,
      "actual": 1.6417700249072606,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=40E0D0&bg=FFFFFF&target=4.5",
      "foreground": "#40E0D0",
      "background": "#FFFFFF",
      "target": 4.5
    },
    {
      "id": "contrast-14",
      "kind": "contrast-reference",
      "label": "Black label on turquoise",
      "inputs": "#000000 on #40E0D0",
      "expected": "12.791072855155965",
      "expectedValue": 12.791072855155965,
      "expectedPass": true,
      "actual": 12.791072855155969,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=000000&bg=40E0D0&target=4.5",
      "foreground": "#000000",
      "background": "#40E0D0",
      "target": 4.5
    },
    {
      "id": "contrast-15",
      "kind": "contrast-reference",
      "label": "White label on yellow fails",
      "inputs": "#FFFF00 on #FFFFFF",
      "expected": "1.0738392309265699",
      "expectedValue": 1.0738392309265699,
      "expectedPass": false,
      "actual": 1.0738392309265699,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=FFFF00&bg=FFFFFF&target=4.5",
      "foreground": "#FFFF00",
      "background": "#FFFFFF",
      "target": 4.5
    },
    {
      "id": "contrast-16",
      "kind": "contrast-reference",
      "label": "Near-white framework foreground fails",
      "inputs": "#FAFAFA on #FFFF00",
      "expected": "1.0288130018912722",
      "expectedValue": 1.0288130018912722,
      "expectedPass": false,
      "actual": 1.0288130018912724,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=FAFAFA&bg=FFFF00&target=4.5",
      "foreground": "#FAFAFA",
      "background": "#FFFF00",
      "target": 4.5
    },
    {
      "id": "contrast-17",
      "kind": "contrast-reference",
      "label": "Black label on yellow",
      "inputs": "#000000 on #FFFF00",
      "expected": "19.556",
      "expectedValue": 19.556,
      "expectedPass": true,
      "actual": 19.555999999999997,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=000000&bg=FFFF00&target=4.5",
      "foreground": "#000000",
      "background": "#FFFF00",
      "target": 4.5
    },
    {
      "id": "contrast-18",
      "kind": "contrast-reference",
      "label": "Pure red and white",
      "inputs": "#FF0000 on #FFFFFF",
      "expected": "3.9984767707539985",
      "expectedValue": 3.9984767707539985,
      "expectedPass": false,
      "actual": 3.9984767707539985,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=FF0000&bg=FFFFFF&target=4.5",
      "foreground": "#FF0000",
      "background": "#FFFFFF",
      "target": 4.5
    },
    {
      "id": "contrast-19",
      "kind": "contrast-reference",
      "label": "Pure blue and white",
      "inputs": "#0000FF on #FFFFFF",
      "expected": "8.592471358428805",
      "expectedValue": 8.592471358428805,
      "expectedPass": true,
      "actual": 8.592471358428805,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=0000FF&bg=FFFFFF&target=7",
      "foreground": "#0000FF",
      "background": "#FFFFFF",
      "target": 7
    },
    {
      "id": "contrast-20",
      "kind": "contrast-reference",
      "label": "Pure green and black",
      "inputs": "#00FF00 on #000000",
      "expected": "15.304",
      "expectedValue": 15.304,
      "expectedPass": true,
      "actual": 15.303999999999998,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=00FF00&bg=000000&target=4.5",
      "foreground": "#00FF00",
      "background": "#000000",
      "target": 4.5
    },
    {
      "id": "contrast-21",
      "kind": "contrast-reference",
      "label": "G183 example link versus body",
      "inputs": "#3366CC on #000000",
      "expected": "3.913236616272322",
      "expectedValue": 3.913236616272322,
      "expectedPass": true,
      "actual": 3.913236616272323,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=3366CC&bg=000000&target=3",
      "foreground": "#3366CC",
      "background": "#000000",
      "target": 3
    },
    {
      "id": "contrast-22",
      "kind": "contrast-reference",
      "label": "G183 example link versus background",
      "inputs": "#3366CC on #FFFFFF",
      "expected": "5.3664017945340134",
      "expectedValue": 5.3664017945340134,
      "expectedPass": true,
      "actual": 5.366401794534013,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=3366CC&bg=FFFFFF&target=4.5",
      "foreground": "#3366CC",
      "background": "#FFFFFF",
      "target": 4.5
    },
    {
      "id": "contrast-23",
      "kind": "contrast-reference",
      "label": "Dark-mode link and background",
      "inputs": "#93C5FD on #111827",
      "expected": "9.837500536060759",
      "expectedValue": 9.837500536060759,
      "expectedPass": true,
      "actual": 9.83750053606076,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=93C5FD&bg=111827&target=4.5",
      "foreground": "#93C5FD",
      "background": "#111827",
      "target": 4.5
    },
    {
      "id": "contrast-24",
      "kind": "contrast-reference",
      "label": "Dark-mode body and background",
      "inputs": "#F9FAFB on #111827",
      "expected": "16.97538624440406",
      "expectedValue": 16.97538624440406,
      "expectedPass": true,
      "actual": 16.97538624440406,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=F9FAFB&bg=111827&target=7",
      "foreground": "#F9FAFB",
      "background": "#111827",
      "target": 7
    },
    {
      "id": "contrast-25",
      "kind": "contrast-reference",
      "label": "Below sRGB transfer breakpoint",
      "inputs": "#0A0A0A on #000000",
      "expected": "1.0607053967097675",
      "expectedValue": 1.0607053967097675,
      "expectedPass": false,
      "actual": 1.0607053967097675,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=0A0A0A&bg=000000&target=4.5",
      "foreground": "#0A0A0A",
      "background": "#000000",
      "target": 4.5
    },
    {
      "id": "contrast-26",
      "kind": "contrast-reference",
      "label": "Above sRGB transfer breakpoint",
      "inputs": "#0B0B0B on #000000",
      "expected": "1.0669307152779832",
      "expectedValue": 1.0669307152779832,
      "expectedPass": false,
      "actual": 1.0669307152779832,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=0B0B0B&bg=000000&target=4.5",
      "foreground": "#0B0B0B",
      "background": "#000000",
      "target": 4.5
    },
    {
      "id": "contrast-27",
      "kind": "contrast-reference",
      "label": "Near-black channels",
      "inputs": "#010203 on #040506",
      "expected": "1.018008327050428",
      "expectedValue": 1.018008327050428,
      "expectedPass": false,
      "actual": 1.018008327050428,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=010203&bg=040506&target=4.5",
      "foreground": "#010203",
      "background": "#040506",
      "target": 4.5
    },
    {
      "id": "contrast-28",
      "kind": "contrast-reference",
      "label": "Pastel collection reading pair",
      "inputs": "#FFF7FA on #382B43",
      "expected": "12.501470391481254",
      "expectedValue": 12.501470391481254,
      "expectedPass": true,
      "actual": 12.501470391481256,
      "tolerance": 1e-10,
      "verified": true,
      "source": "https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html",
      "reproducePath": "/contrast-checker?fg=FFF7FA&bg=382B43&target=7",
      "foreground": "#FFF7FA",
      "background": "#382B43",
      "target": 7
    },
    {
      "id": "difference-01",
      "kind": "difference-reference",
      "label": "Sharma reference pair 1",
      "inputs": "Lab (50, 2.6772, -79.7751) / (50, 0, -82.7485)",
      "labFirst": {
        "l": 50,
        "a": 2.6772,
        "b": -79.7751
      },
      "labSecond": {
        "l": 50,
        "a": 0,
        "b": -82.7485
      },
      "expected": "2.0425",
      "expectedValue": 2.0425,
      "actual": 2.042459680156577,
      "tolerance": 0.00005,
      "verified": true,
      "source": "https://hajim.rochester.edu/ece/sites/gsharma/ciede2000/",
      "reproducePath": "/validation#difference-01"
    },
    {
      "id": "difference-02",
      "kind": "difference-reference",
      "label": "Sharma reference pair 2",
      "inputs": "Lab (50, 3.1571, -77.2803) / (50, 0, -82.7485)",
      "labFirst": {
        "l": 50,
        "a": 3.1571,
        "b": -77.2803
      },
      "labSecond": {
        "l": 50,
        "a": 0,
        "b": -82.7485
      },
      "expected": "2.8615",
      "expectedValue": 2.8615,
      "actual": 2.8615101747474916,
      "tolerance": 0.00005,
      "verified": true,
      "source": "https://hajim.rochester.edu/ece/sites/gsharma/ciede2000/",
      "reproducePath": "/validation#difference-02"
    },
    {
      "id": "difference-03",
      "kind": "difference-reference",
      "label": "Sharma reference pair 3",
      "inputs": "Lab (50, 2.8361, -74.02) / (50, 0, -82.7485)",
      "labFirst": {
        "l": 50,
        "a": 2.8361,
        "b": -74.02
      },
      "labSecond": {
        "l": 50,
        "a": 0,
        "b": -82.7485
      },
      "expected": "3.4412",
      "expectedValue": 3.4412,
      "actual": 3.4411905986907065,
      "tolerance": 0.00005,
      "verified": true,
      "source": "https://hajim.rochester.edu/ece/sites/gsharma/ciede2000/",
      "reproducePath": "/validation#difference-03"
    },
    {
      "id": "difference-04",
      "kind": "difference-reference",
      "label": "Sharma reference pair 4",
      "inputs": "Lab (50, -1.3802, -84.2814) / (50, 0, -82.7485)",
      "labFirst": {
        "l": 50,
        "a": -1.3802,
        "b": -84.2814
      },
      "labSecond": {
        "l": 50,
        "a": 0,
        "b": -82.7485
      },
      "expected": "1",
      "expectedValue": 1,
      "actual": 0.999998864752493,
      "tolerance": 0.00005,
      "verified": true,
      "source": "https://hajim.rochester.edu/ece/sites/gsharma/ciede2000/",
      "reproducePath": "/validation#difference-04"
    },
    {
      "id": "difference-05",
      "kind": "difference-reference",
      "label": "Sharma reference pair 5",
      "inputs": "Lab (50, -1.1848, -84.8006) / (50, 0, -82.7485)",
      "labFirst": {
        "l": 50,
        "a": -1.1848,
        "b": -84.8006
      },
      "labSecond": {
        "l": 50,
        "a": 0,
        "b": -82.7485
      },
      "expected": "1",
      "expectedValue": 1,
      "actual": 1.0000047010743665,
      "tolerance": 0.00005,
      "verified": true,
      "source": "https://hajim.rochester.edu/ece/sites/gsharma/ciede2000/",
      "reproducePath": "/validation#difference-05"
    },
    {
      "id": "difference-06",
      "kind": "difference-reference",
      "label": "Sharma reference pair 6",
      "inputs": "Lab (50, -0.9009, -85.5211) / (50, 0, -82.7485)",
      "labFirst": {
        "l": 50,
        "a": -0.9009,
        "b": -85.5211
      },
      "labSecond": {
        "l": 50,
        "a": 0,
        "b": -82.7485
      },
      "expected": "1",
      "expectedValue": 1,
      "actual": 1.0000129676236045,
      "tolerance": 0.00005,
      "verified": true,
      "source": "https://hajim.rochester.edu/ece/sites/gsharma/ciede2000/",
      "reproducePath": "/validation#difference-06"
    },
    {
      "id": "fix-01",
      "kind": "fix-invariant",
      "label": "Gray just below AA on white",
      "inputs": "#777777 on #FFFFFF",
      "expected": "Final sRGB contrast ≥ 4.5; passing input unchanged",
      "actual": 4.542224959605253,
      "tolerance": null,
      "verified": true,
      "source": "/methodology",
      "reproducePath": "/contrast-checker?fg=777777&bg=FFFFFF&target=4.5",
      "foreground": "#777777",
      "background": "#FFFFFF",
      "adjustedForeground": "#767676",
      "target": 4.5
    },
    {
      "id": "fix-02",
      "kind": "fix-invariant",
      "label": "Turquoise text on white",
      "inputs": "#40E0D0 on #FFFFFF",
      "expected": "Final sRGB contrast ≥ 4.5; passing input unchanged",
      "actual": 4.53455320755997,
      "tolerance": null,
      "verified": true,
      "source": "/methodology",
      "reproducePath": "/contrast-checker?fg=40E0D0&bg=FFFFFF&target=4.5",
      "foreground": "#40E0D0",
      "background": "#FFFFFF",
      "adjustedForeground": "#008579",
      "target": 4.5
    },
    {
      "id": "fix-03",
      "kind": "fix-invariant",
      "label": "Gray on black with a 7:1 target",
      "inputs": "#777777 on #000000",
      "expected": "Final sRGB contrast ≥ 7; passing input unchanged",
      "actual": 7.010875888315529,
      "tolerance": null,
      "verified": true,
      "source": "/methodology",
      "reproducePath": "/contrast-checker?fg=777777&bg=000000&target=7",
      "foreground": "#777777",
      "background": "#000000",
      "adjustedForeground": "#959595",
      "target": 7
    },
    {
      "id": "fix-04",
      "kind": "fix-invariant",
      "label": "Impossible 7:1 on a mid-gray background",
      "inputs": "#FFFFFF on #777777",
      "expected": "No color reaches 7:1 on this fixed background",
      "actual": 4.478089453577214,
      "tolerance": null,
      "verified": true,
      "source": "/methodology",
      "reproducePath": "/contrast-checker?fg=FFFFFF&bg=777777&target=7",
      "foreground": "#FFFFFF",
      "background": "#777777",
      "adjustedForeground": "#FFFFFF",
      "target": 7
    },
    {
      "id": "fix-05",
      "kind": "fix-invariant",
      "label": "Already readable color stays unchanged",
      "inputs": "#111827 on #FFFFFF",
      "expected": "Final sRGB contrast ≥ 4.5; passing input unchanged",
      "actual": 17.73971700407407,
      "tolerance": null,
      "verified": true,
      "source": "/methodology",
      "reproducePath": "/contrast-checker?fg=111827&bg=FFFFFF&target=4.5",
      "foreground": "#111827",
      "background": "#FFFFFF",
      "adjustedForeground": "#111827",
      "target": 4.5
    },
    {
      "id": "fix-06",
      "kind": "fix-invariant",
      "label": "Saturated yellow rechecked after sRGB rounding",
      "inputs": "#FFFF00 on #FFFFFF",
      "expected": "Final sRGB contrast ≥ 4.5; passing input unchanged",
      "actual": 4.528444404189377,
      "tolerance": null,
      "verified": true,
      "source": "/methodology",
      "reproducePath": "/contrast-checker?fg=FFFF00&bg=FFFFFF&target=4.5",
      "foreground": "#FFFF00",
      "background": "#FFFFFF",
      "adjustedForeground": "#7F7900",
      "target": 4.5
    }
  ]
}