.chain-page { background: radial-gradient(circle at 82% 0, rgba(255, 182, 0, 0.1), transparent 46%), linear-gradient(180deg, #fffefb, #fdfbf6 72%, #faf8f0); }
.chain-shell { width: min(1080px, calc(100% - 64px)); margin: 0 auto; padding: 144px 0 48px; }
.chain-intro { margin-bottom: 36px; }
.chain-intro .brand-eyebrow { margin-bottom: 14px; color: #8e6000; }
.chain-intro h1 { margin: 0 0 16px; font: 700 64px/0.95 var(--serif); letter-spacing: -0.065em; }
.chain-lede { margin: 0; color: var(--muted); font-size: 18px; line-height: 1.55; }
.chain-workspace { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 48px; }
.chain-form-heading { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-bottom: 20px; }
.chain-form-heading h2 { margin: 0; font: 700 28px/1.1 var(--serif); letter-spacing: -0.04em; }
.chain-field { min-width: 0; margin: 0 0 20px; padding: 0; border: 0; }
.chain-field > label, .chain-field legend { display: block; padding: 0; margin-bottom: 8px; color: var(--muted); font-size: 12px; font-weight: 800; letter-spacing: 0.09em; text-transform: uppercase; }
.chain-options { display: flex; }
.chain-options label { position: relative; flex: 1; min-width: 0; cursor: pointer; }
.chain-options input, .chain-sr-only { position: absolute; width: 1px; height: 1px; padding: 0; overflow: hidden; clip-path: inset(50%); white-space: nowrap; }
.chain-options label > span { display: flex; align-items: center; justify-content: center; min-height: 46px; border: 1px solid var(--line); background: rgba(255, 255, 255, 0.64); color: var(--muted); font-size: 14px; font-weight: 700; }
.chain-options label + label > span { border-left: 0; }
.chain-options label:first-child > span { border-radius: 8px 0 0 8px; }
.chain-options label:last-child > span { border-radius: 0 8px 8px 0; }
.chain-options input:checked + span { background: var(--paper); color: var(--ink); box-shadow: inset 0 0 0 1px var(--ink); }
.chain-form :focus-visible, .chain-options input:focus-visible + span { outline: 3px solid rgba(255, 182, 0, 0.72); outline-offset: 3px; }
.chain-sprockets { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; }
.chain-input-wrap { display: flex; align-items: center; min-width: 0; min-height: 50px; border: 1px solid var(--line); border-radius: 8px; background: var(--paper); box-shadow: inset 0 1px 2px rgba(27, 26, 23, 0.04); }
.chain-input-wrap:focus-within { border-color: var(--ink); outline: 3px solid rgba(255, 182, 0, 0.72); outline-offset: 3px; }
.chain-input-wrap input { width: 100%; min-width: 0; padding: 10px 12px; border: 0; outline: none; background: transparent; color: var(--ink); font: 600 18px/1.4 var(--sans); font-variant-numeric: tabular-nums; appearance: textfield; }
.chain-input-wrap input:focus-visible { outline: none; }
.chain-input-wrap input::-webkit-inner-spin-button, .chain-input-wrap input::-webkit-outer-spin-button { appearance: none; margin: 0; }
.chain-input-wrap > span { padding-right: 12px; color: var(--muted); font-size: 13px; }
.chain-input-wrap:has([aria-invalid='true']) { border-color: #ad2929; }
.chain-spacing-row { display: grid; grid-template-columns: minmax(0, 1fr) 110px; gap: 12px; }
.chain-unit { min-width: 0; margin: 0; padding: 0; border: 0; }
.chain-unit .chain-options, .chain-unit .chain-options label > span { height: 100%; }
.chain-spacing { margin-bottom: 12px; }
.chain-error { margin: 7px 0 0; color: #ad2929; font-size: 13px; line-height: 1.4; }
.chain-error:empty { display: none; }
.chain-calculate { width: 100%; border-color: rgba(255, 196, 39, 0.92); background: linear-gradient(180deg, #ffc82e, var(--yellow)); color: var(--ink); box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.4), inset 0 -1px 0 rgba(153, 91, 0, 0.24), 0 10px 24px rgba(255, 182, 0, 0.2); font-family: var(--sans); cursor: pointer; }
.chain-calculate:hover, .chain-calculate:focus-visible { background: linear-gradient(180deg, #ffd04a, #ffb300); box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.48), inset 0 -1px 0 rgba(153, 91, 0, 0.28), 0 14px 30px rgba(255, 182, 0, 0.26); }
.chain-output { min-width: 0; padding: 8px 0 0 48px; border-left: 1px solid var(--line); }
.chain-output [hidden] { display: none; }
.chain-output-label { margin: 0 0 16px; color: var(--muted); font-size: 12px; font-weight: 800; letter-spacing: 0.09em; text-transform: uppercase; }
.chain-link-count { display: flex; flex-wrap: wrap; align-items: baseline; gap: 10px; margin: 0; font: 650 54px/1.05 var(--sans); letter-spacing: -0.05em; font-variant-numeric: tabular-nums; }
.chain-link-count strong { font: inherit; }
.chain-result-type { margin: 10px 0 0; font-size: 15px; }
.chain-fit { margin: 24px 0 18px; padding: 18px 0; border-block: 1px solid var(--line); }
.chain-fit > div { display: flex; align-items: baseline; justify-content: space-between; gap: 16px; }
.chain-fit > div + div { margin-top: 10px; }
.chain-fit dt { color: var(--muted); font-size: 14px; }
.chain-fit dd { margin: 0; text-align: right; font-size: 15px; font-weight: 650; font-variant-numeric: tabular-nums; }
.chain-result-note, .chain-pending { max-width: 34ch; margin: 0; color: var(--muted); font-size: 13px; line-height: 1.55; }
.chain-pending { min-height: 216px; padding-top: 16px; }
.chain-measure summary { display: flex; align-items: center; justify-content: space-between; gap: 16px; min-height: 46px; list-style: none; cursor: pointer; font-size: 14px; }
.chain-measure summary { color: var(--muted); text-decoration: underline; text-underline-offset: 3px; }
.chain-measure summary::-webkit-details-marker { display: none; }
.chain-measure summary svg { flex: 0 0 16px; width: 16px; height: 16px; fill: none; stroke: currentColor; stroke-width: 1.5; }
.chain-measure[open] > summary svg { transform: rotate(180deg); }
.chain-measure-content { padding-bottom: 12px; }
.chain-measure-content p { max-width: 68ch; color: var(--muted); font-size: 14px; line-height: 1.65; }
.chain-measure-content p { margin: 6px 0; }
.chain-diagram { display: block; width: 100%; max-width: 400px; height: auto; margin-top: 16px; color: var(--muted); }
.chain-diagram text { fill: currentColor; font: 14px var(--sans); }
.chain-measure-content .chain-caption { font-size: 12px; }
.chain-privacy { margin: 24px 0 0; color: var(--muted); font-size: 12px; }
.chain-history { position: relative; flex-shrink: 0; }
.chain-history[hidden], .chain-history-options[hidden] { display: none; }
.chain-history-toggle { display: flex; align-items: center; justify-content: space-between; gap: 12px; min-height: 44px; padding: 0 12px; border: 1px solid var(--line); border-radius: 8px; background: transparent; color: var(--muted); font: 600 13px var(--sans); cursor: pointer; }
.chain-history-toggle svg { width: 14px; height: 14px; fill: none; stroke: currentColor; stroke-width: 1.5; }
.chain-history-toggle[aria-expanded='true'] { border-color: var(--ink); color: var(--ink); background: var(--paper); }
.chain-history-toggle[aria-expanded='true'] svg { transform: rotate(180deg); }
.chain-history-options { position: absolute; z-index: 10; top: calc(100% + 8px); right: 0; width: min(290px, calc(100vw - 40px)); padding: 6px; border: 1px solid var(--line); border-radius: 10px; background: #fffefb; box-shadow: 0 12px 32px rgba(27, 26, 23, 0.14); }
.chain-history-options button { display: grid; gap: 3px; width: 100%; min-height: 60px; padding: 10px 12px; border: 0; border-radius: 5px; background: transparent; color: var(--ink); text-align: left; font: 13px/1.4 var(--sans); cursor: pointer; }
.chain-history-options button + button { border-top: 1px solid var(--line); }
.chain-history-options button span { color: var(--muted); font-size: 12px; }
.chain-history-options button:hover, .chain-history-options button:focus-visible { background: #fff0c7; }
.chain-history-options button:focus-visible { outline: 2px solid var(--yellow); outline-offset: -2px; }
@media (prefers-reduced-motion: reduce) { .chain-calculate { transition: none; } }
@media (max-width: 700px) {
  .chain-shell { width: calc(100% - 40px); padding-top: 108px; }
  .chain-intro { margin-bottom: 24px; }
  .chain-intro .brand-eyebrow { margin-bottom: 10px; font-size: 10px; }
  .chain-intro h1 { margin-bottom: 12px; font-size: 42px; }
  .chain-lede { max-width: 34ch; font-size: 15px; }
  .chain-form-heading h2 { font-size: 25px; }
  .chain-workspace { grid-template-columns: 1fr; gap: 22px; }
  .chain-form-heading { margin-bottom: 16px; }
  .chain-field { margin-bottom: 16px; }
  .chain-sprockets { gap: 14px; }
  .chain-spacing { margin-bottom: 8px; }
  .chain-output { padding: 18px 0 0; border-top: 1px solid var(--line); border-left: 0; }
  .chain-output-label { margin-bottom: 8px; }
  .chain-link-count { font-size: 44px; }
  .chain-result-type { margin-top: 4px; font-size: 13px; }
  .chain-fit { margin: 14px 0 10px; padding: 12px 0 0; border-bottom: 0; }
  .chain-fit > div + div { margin-top: 5px; }
  .chain-pending { min-height: 190px; }
}