curl --request POST \
  --url https://api.iotools.cloud/v1/tool/css-fluid-typography-generator \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "minFontSize": "16",
  "maxFontSize": "20",
  "minViewport": "320",
  "maxViewport": "1200",
  "minRatio": "1.2",
  "maxRatio": "1.25",
  "outputUnit": "rem",
  "asCustomProperties": "true"
}
'

{
  "tool": "css-fluid-typography-generator",
  "tool_version": "1.0.1",
  "outputs": {
    "cssCode": ":root {\n  --font-xs: clamp(0.6944rem, 0.6561rem + 0.1919vw, 0.8rem);\n  --font-sm: clamp(0.8333rem, 0.7727rem + 0.303vw, 1rem);\n  --font-base: clamp(1rem, 0.9091rem + 0.4545vw, 1.25rem);\n  --font-lg: clamp(1.2rem, 1.0682rem + 0.6591vw, 1.5625rem);\n  --font-xl: clamp(1.44rem, 1.2534rem + 0.933vw, 1.9531rem);\n  --font-2xl: clamp(1.728rem, 1.4686rem + 1.2971vw, 2.4414rem);\n  --font-3xl: clamp(2.0736rem, 1.7179rem + 1.7785vw, 3.0518rem);\n  --font-4xl: clamp(2.4883rem, 2.006rem + 2.4116vw, 3.8147rem);\n}\n\n/* Usage */\nh1 { font-size: var(--font-3xl); }\np  { font-size: var(--font-base); }",
    "scaleTable": [
      {
        "step": "XS",
        "min": "0.6944rem",
        "max": "0.8rem",
        "clamp": "clamp(0.6944rem, 0.6561rem + 0.1919vw, 0.8rem)"
      },
      {
        "step": "SM",
        "min": "0.8333rem",
        "max": "1rem",
        "clamp": "clamp(0.8333rem, 0.7727rem + 0.303vw, 1rem)"
      },
      {
        "step": "Base",
        "min": "1rem",
        "max": "1.25rem",
        "clamp": "clamp(1rem, 0.9091rem + 0.4545vw, 1.25rem)"
      },
      {
        "step": "LG",
        "min": "1.2rem",
        "max": "1.5625rem",
        "clamp": "clamp(1.2rem, 1.0682rem + 0.6591vw, 1.5625rem)"
      },
      {
        "step": "XL",
        "min": "1.44rem",
        "max": "1.9531rem",
        "clamp": "clamp(1.44rem, 1.2534rem + 0.933vw, 1.9531rem)"
      },
      {
        "step": "2XL",
        "min": "1.728rem",
        "max": "2.4414rem",
        "clamp": "clamp(1.728rem, 1.4686rem + 1.2971vw, 2.4414rem)"
      },
      {
        "step": "3XL",
        "min": "2.0736rem",
        "max": "3.0518rem",
        "clamp": "clamp(2.0736rem, 1.7179rem + 1.7785vw, 3.0518rem)"
      },
      {
        "step": "4XL",
        "min": "2.4883rem",
        "max": "3.8147rem",
        "clamp": "clamp(2.4883rem, 2.006rem + 2.4116vw, 3.8147rem)"
      }
    ],
    "previewHtml": "<div class=\"io-ftg-demo\"><p class=\"io-ftg-xs\">The quick brown fox — XS</p><p class=\"io-ftg-sm\">The quick brown fox — SM</p><p class=\"io-ftg-base\">The quick brown fox — Base</p><p class=\"io-ftg-lg\">The quick brown fox — LG</p><p class=\"io-ftg-xl\">The quick brown fox — XL</p><p class=\"io-ftg-2xl\">The quick brown fox — 2XL</p><p class=\"io-ftg-3xl\">The quick brown fox — 3XL</p><p class=\"io-ftg-4xl\">The quick brown fox — 4XL</p></div>",
    "previewCss": ".io-ftg-demo { font-family: system-ui, sans-serif; color: #1a1a2e; }\n.io-ftg-demo p { margin: 0 0 0.5em 0; line-height: 1.3; }\n.io-ftg-xs { font-size: clamp(0.6944rem, 0.6561rem + 0.1919vw, 0.8rem); }\n.io-ftg-sm { font-size: clamp(0.8333rem, 0.7727rem + 0.303vw, 1rem); }\n.io-ftg-base { font-size: clamp(1rem, 0.9091rem + 0.4545vw, 1.25rem); }\n.io-ftg-lg { font-size: clamp(1.2rem, 1.0682rem + 0.6591vw, 1.5625rem); }\n.io-ftg-xl { font-size: clamp(1.44rem, 1.2534rem + 0.933vw, 1.9531rem); }\n.io-ftg-2xl { font-size: clamp(1.728rem, 1.4686rem + 1.2971vw, 2.4414rem); }\n.io-ftg-3xl { font-size: clamp(2.0736rem, 1.7179rem + 1.7785vw, 3.0518rem); }\n.io-ftg-4xl { font-size: clamp(2.4883rem, 2.006rem + 2.4116vw, 3.8147rem); }"
  },
  "credits_used": 3,
  "credits_remaining": null
}