{
  "id": "SC-2.3.1",
  "rulePrefix": "SC-2.3.1",
  "variant": null,
  "ruleType": "synthetic-sc",
  "scanScope": "specimen",
  "synthetic": true,
  "status": "current",
  "title": "Flashing promotional banner",
  "summary": "A banner flashes more than three times per second.",
  "whyItFails": "Photosensitive users may experience seizures or physical reactions because the animation exceeds safe flash thresholds.",
  "principles": [
    "operable"
  ],
  "guidelines": [
    "2.3"
  ],
  "successCriteria": [
    {
      "id": "2.3.1",
      "name": "Three Flashes or Below Threshold",
      "level": "A",
      "slug": "three-flashes-or-below-threshold"
    }
  ],
  "versions": [
    "2.0",
    "2.1",
    "2.2"
  ],
  "automatable": "partial",
  "requires": [
    "css",
    "motion"
  ],
  "isolated": true,
  "pairWith": [],
  "w3c": {
    "understanding": [
      "https://www.w3.org/WAI/WCAG22/Understanding/three-flashes-or-below-threshold"
    ],
    "quickref": [
      "https://www.w3.org/WAI/WCAG22/quickref/#three-flashes-or-below-threshold"
    ]
  },
  "specimen": {
    "html": "<div class=\"sc231-flash\"></div>\n<p>Large flashing area may exceed three flashes per second.</p>",
    "css": ".sc231-flash { width:100%;height:120px;animation:sc231-blink 0.25s linear infinite; }\n@keyframes sc231-blink { 0%,49%{background:#fff;} 50%,100%{background:#f00;} }",
    "js": "",
    "assets": []
  },
  "expectedFindings": [
    {
      "sc": "2.3.1",
      "outcome": "fail",
      "note": "Specimen demonstrates failure of 2.3.1."
    }
  ],
  "mustNotFlag": [],
  "manualCheck": "Measure flash frequency and confirm it exceeds three flashes per second.",
  "generated": {
    "url": "https://wcagfail.patternd.io/specimens/SC-2.3.1/",
    "lastmod": "2026-10-08"
  }
}