@layer reset, base, layout, components, utilities, responsive, print;

@layer reset {
  *,
  *::before,
  *::after {
    box-sizing: border-box;
  }

  html {
    scroll-behavior: smooth;
    text-size-adjust: 100%;
  }

  body,
  h1,
  h2,
  h3,
  h4,
  p,
  ul,
  ol,
  dl,
  dd,
  figure,
  fieldset {
    margin: 0;
  }

  ul,
  ol {
    padding: 0;
  }

  button,
  input,
  select,
  textarea {
    font: inherit;
  }

  button,
  select {
    color: inherit;
  }

  button {
    border: 0;
  }

  img,
  svg {
    display: block;
    max-width: 100%;
  }

  table {
    border-collapse: collapse;
    border-spacing: 0;
  }

  [hidden] {
    display: none !important;
  }
}

@layer base {
  :root {
    --canvas: #f3ebdd;
    --paper: #fffdf8;
    --paper-deep: #ebe0d0;
    --ink: #211a18;
    --ink-soft: #4e4540;
    --muted: #746861;
    --faint: #9b8d84;
    --line: #cdbfaf;
    --line-strong: #9a877b;
    --accent: #7a2331;
    --accent-dark: #591321;
    --accent-soft: #ead6d8;
    --clay: #b67a6b;
    --success: #315f4a;
    --success-soft: #dce9df;
    --warning: #81570d;
    --warning-soft: #f5e6c7;
    --danger: #8a2525;
    --danger-soft: #f5dcdc;
    --focus: #7a2331;
    --serif: Georgia, "Times New Roman", Times, serif;
    --sans: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    --mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
    --page-pad: clamp(1rem, 3vw, 2.5rem);
    --content: 1120px;
    --header-height: 76px;
    --radius-sm: 6px;
    --radius: 12px;
    --radius-lg: 22px;
    --transition-fast: 150ms ease-out;
    --transition-panel: 240ms cubic-bezier(0.2, 0, 0, 1);
  }

  body {
    min-width: 320px;
    min-height: 100vh;
    overflow-x: hidden;
    background: var(--canvas);
    color: var(--ink);
    font-family: var(--sans);
    font-size: 1rem;
    line-height: 1.55;
    -webkit-font-smoothing: antialiased;
  }

  body::before {
    position: fixed;
    inset: 0;
    z-index: -1;
    pointer-events: none;
    content: "";
    opacity: 0.34;
    background-image:
      repeating-linear-gradient(90deg, transparent 0, transparent 47px, rgba(33, 26, 24, 0.045) 48px),
      repeating-linear-gradient(0deg, transparent 0, transparent 47px, rgba(33, 26, 24, 0.045) 48px);
  }

  a {
    color: var(--accent-dark);
    text-decoration-thickness: 1px;
    text-underline-offset: 0.18em;
  }

  a:hover {
    text-decoration-thickness: 2px;
  }

  button,
  input,
  select,
  dialog {
    font-family: var(--sans);
  }

  button,
  select,
  input[type="checkbox"],
  input[type="radio"] {
    cursor: pointer;
  }

  input,
  select {
    min-width: 0;
  }

  :focus-visible {
    outline: 3px solid var(--focus);
    outline-offset: 3px;
  }

  ::selection {
    background: var(--accent);
    color: var(--paper);
  }

  h1,
  h2,
  h3 {
    text-wrap: balance;
  }

  h1,
  h2 {
    font-family: var(--serif);
    font-weight: 700;
    letter-spacing: -0.035em;
    line-height: 0.98;
  }

  h1 {
    max-width: 13ch;
    font-size: clamp(2.65rem, 6vw, 5.35rem);
  }

  h2 {
    font-size: clamp(2.15rem, 4vw, 3.85rem);
  }

  h3 {
    font-size: clamp(1.15rem, 2vw, 1.45rem);
    line-height: 1.2;
  }

  small {
    color: var(--muted);
  }

  kbd {
    display: inline-grid;
    min-width: 2rem;
    min-height: 2rem;
    place-items: center;
    border: 1px solid var(--line-strong);
    border-bottom-width: 3px;
    border-radius: 5px;
    background: var(--paper);
    color: var(--ink);
    font-family: var(--mono);
    font-size: 0.85rem;
  }
}

@layer layout {
  .header-inner,
  .tool-stage,
  .reference-content,
  .trust-band,
  .footer-inner {
    width: min(100% - (var(--page-pad) * 2), var(--content));
    margin-inline: auto;
  }

  .site-header {
    position: sticky;
    z-index: 30;
    top: 0;
    min-height: var(--header-height);
    border-bottom: 1px solid var(--ink);
    background: color-mix(in srgb, var(--canvas) 94%, transparent);
    backdrop-filter: blur(14px);
  }

  .header-inner {
    display: grid;
    min-height: var(--header-height);
    grid-template-columns: minmax(190px, 1fr) auto minmax(110px, 1fr);
    align-items: center;
    gap: 1.25rem;
  }

  .brand {
    display: inline-flex;
    width: max-content;
    align-items: center;
    gap: 0.7rem;
    color: inherit;
    text-decoration: none;
  }

  .brand img {
    flex: 0 0 auto;
  }

  .brand-copy {
    display: grid;
    line-height: 1.08;
  }

  .brand-copy strong {
    font-family: var(--serif);
    font-size: 1.08rem;
  }

  .brand-copy span {
    margin-top: 0.25rem;
    color: var(--muted);
    font-size: 0.72rem;
    letter-spacing: 0.055em;
    text-transform: uppercase;
  }

  .mode-nav {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.15rem;
  }

  .header-actions {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: 0.45rem;
  }

  main {
    display: block;
  }

  .tool-stage {
    padding-block: clamp(1.25rem, 3vw, 2.5rem) clamp(3rem, 7vw, 6rem);
  }

  .measure-workbench {
    display: grid;
    min-height: calc(100dvh - var(--header-height) - 5rem);
    grid-template-columns: minmax(0, 5fr) minmax(430px, 7fr);
    align-items: start;
    gap: clamp(1.25rem, 3vw, 2.75rem);
  }

  .measure-input-pane {
    min-width: 0;
    padding-top: clamp(0.25rem, 2vh, 1.5rem);
  }

  .result-ledger {
    position: sticky;
    top: calc(var(--header-height) + 1.5rem);
    min-width: 0;
    min-height: min(710px, calc(100dvh - var(--header-height) - 3rem));
    overflow: hidden;
    border: 2px solid var(--ink);
    border-radius: var(--radius-lg);
    background: var(--paper);
  }

  .result-empty,
  .result-content {
    padding: clamp(1.25rem, 2.4vw, 2rem);
  }

  .mode-layout {
    display: grid;
    gap: clamp(2rem, 5vw, 4.5rem);
  }

  .mode-intro {
    display: grid;
    max-width: 820px;
    gap: 1rem;
    padding-top: clamp(1rem, 3vw, 2rem);
  }

  .mode-intro p:last-child {
    max-width: 70ch;
    color: var(--ink-soft);
    font-size: clamp(1.05rem, 2vw, 1.25rem);
  }

  .mode-workbench {
    display: grid;
    border-block: 1px solid var(--ink);
    background: var(--paper);
  }

  .mode-workbench--converter,
  .mode-workbench--sister {
    grid-template-columns: minmax(280px, 0.8fr) minmax(0, 1.6fr);
  }

  .size-entry-form {
    display: grid;
    align-content: start;
    gap: 1.1rem;
    padding: clamp(1.4rem, 3vw, 2.4rem);
    border-right: 1px solid var(--ink);
    background: var(--paper-deep);
  }

  .conversion-result,
  .sister-result {
    padding: clamp(1.4rem, 3vw, 2.7rem);
  }

  .fit-workbench {
    display: grid;
    grid-template-columns: minmax(270px, 0.8fr) minmax(0, 1.6fr);
    border-block: 1px solid var(--ink);
    background: var(--paper);
  }

  .fit-size-column {
    border-right: 1px solid var(--ink);
    background: var(--paper-deep);
  }

  .fit-symptom-column {
    padding: clamp(1.4rem, 3vw, 2.5rem);
  }

  .fit-plan {
    border: 2px solid var(--ink);
    border-radius: var(--radius-lg);
    background: var(--paper);
    padding: clamp(1.4rem, 3vw, 2.5rem);
  }

  .reference-content {
    display: grid;
    grid-template-columns: minmax(260px, 0.8fr) minmax(0, 1.7fr);
    gap: clamp(2rem, 6vw, 6rem);
    padding-block: clamp(4rem, 10vw, 9rem);
    border-top: 1px solid var(--ink);
  }

  .reference-intro {
    align-self: start;
    position: sticky;
    top: calc(var(--header-height) + 2rem);
  }

  .reference-intro h2 {
    margin-top: 0.8rem;
  }

  .reference-intro > p:last-child {
    margin-top: 1.35rem;
    color: var(--ink-soft);
  }

  .reference-sections {
    display: grid;
    border-top: 1px solid var(--ink);
  }

  .trust-band {
    display: grid;
    grid-template-columns: minmax(240px, 0.8fr) minmax(0, 1.6fr);
    gap: clamp(2rem, 6vw, 6rem);
    padding-block: clamp(3rem, 7vw, 5rem);
    border-block: 1px solid var(--ink);
  }

  .trust-copy {
    max-width: 70ch;
    color: var(--ink-soft);
  }

  .trust-copy .plain-link {
    margin-top: 1rem;
  }

  .site-footer {
    background: var(--ink);
    color: var(--paper);
  }

  .footer-inner {
    display: grid;
    grid-template-columns: minmax(190px, 0.7fr) minmax(260px, 1.4fr);
    gap: 2rem;
    padding-block: 2.5rem;
  }

  .footer-inner > div strong {
    font-family: var(--serif);
    font-size: 1.35rem;
  }

  .footer-inner > div p,
  .release-line {
    margin-top: 0.45rem;
    color: #cbbfb5;
    font-size: 0.85rem;
  }

  .footer-inner nav {
    display: flex;
    flex-wrap: wrap;
    align-content: start;
    justify-content: flex-end;
    gap: 0.4rem 1rem;
  }

  .footer-inner nav button {
    display: inline-flex;
    align-items: center;
    min-height: 44px;
    padding: 0.4rem 0;
    background: transparent;
    color: var(--paper);
    text-decoration: underline;
    text-decoration-color: #756a64;
    text-underline-offset: 0.25em;
  }

  .release-line {
    grid-column: 1 / -1;
    padding-top: 1.2rem;
    border-top: 1px solid #534945;
  }
}

@layer components {
  .skip-link {
    position: fixed;
    z-index: 100;
    top: 0.75rem;
    left: 0.75rem;
    transform: translateY(-160%);
    border: 2px solid var(--ink);
    background: var(--paper);
    padding: 0.7rem 1rem;
    color: var(--ink);
    font-weight: 700;
    transition: transform var(--transition-fast);
  }

  .skip-link:focus {
    transform: translateY(0);
  }

  .mode-button,
  .text-button,
  .icon-button,
  .plain-link,
  .guide-link {
    background: transparent;
  }

  .mode-button {
    min-height: 44px;
    border-radius: 999px;
    padding: 0.55rem 0.85rem;
    color: var(--muted);
    font-size: 0.86rem;
    font-weight: 700;
    transition: color var(--transition-fast), background-color var(--transition-fast);
  }

  .mode-button:hover {
    color: var(--ink);
  }

  .mode-button.is-active,
  .mode-button[aria-pressed="true"] {
    background: var(--ink);
    color: var(--paper);
  }

  .text-button {
    min-height: 44px;
    border-bottom: 1px solid currentColor;
    padding: 0.45rem 0.2rem;
    font-weight: 700;
  }

  .icon-button {
    display: inline-grid;
    width: 44px;
    height: 44px;
    flex: 0 0 44px;
    place-items: center;
    border: 1px solid var(--line-strong);
    border-radius: 50%;
    color: inherit;
    font-size: 1.25rem;
    font-weight: 700;
    line-height: 1;
    transition: border-color var(--transition-fast), background-color var(--transition-fast);
  }

  .icon-button:hover {
    border-color: var(--ink);
    background: var(--paper-deep);
  }

  .eyebrow {
    color: var(--accent);
    font-size: 0.76rem;
    font-weight: 800;
    letter-spacing: 0.13em;
    text-transform: uppercase;
  }

  .privacy-dot {
    display: inline-block;
    width: 0.55rem;
    height: 0.55rem;
    margin-right: 0.45rem;
    border-radius: 50%;
    background: var(--success);
  }

  .lede {
    max-width: 57ch;
    margin-top: 1.25rem;
    color: var(--ink-soft);
    font-size: clamp(1.05rem, 1.7vw, 1.2rem);
  }

  .control-row {
    display: flex;
    flex-wrap: wrap;
    align-items: end;
    gap: 1rem;
  }

  .control-row--preferences {
    margin-top: clamp(1.4rem, 3vw, 2rem);
    padding-block: 1rem;
    border-block: 1px solid var(--line-strong);
  }

  fieldset {
    min-width: 0;
    border: 0;
    padding: 0;
  }

  legend,
  .select-field > span,
  .measurement-field label,
  .group-heading > span {
    color: var(--ink);
    font-size: 0.8rem;
    font-weight: 800;
    letter-spacing: 0.045em;
    text-transform: uppercase;
  }

  .compact-fieldset {
    flex: 1 1 225px;
  }

  .compact-fieldset legend,
  .method-fieldset legend {
    margin-bottom: 0.55rem;
  }

  .segmented {
    display: grid;
    overflow: hidden;
    border: 1px solid var(--ink);
    border-radius: var(--radius);
    background: var(--paper);
  }

  .segmented--small {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .segmented button {
    min-height: 48px;
    padding: 0.65rem 0.9rem;
    background: transparent;
    color: var(--ink-soft);
    font-weight: 700;
    transition: background-color var(--transition-fast), color var(--transition-fast);
  }

  .segmented button + button {
    border-left: 1px solid var(--ink);
  }

  .segmented button:hover {
    background: var(--paper-deep);
  }

  .segmented button[aria-pressed="true"] {
    background: var(--ink);
    color: var(--paper);
  }

  .select-field {
    display: grid;
    gap: 0.45rem;
    min-width: 0;
  }

  .select-field--compact {
    flex: 1 1 190px;
  }

  .select-field select {
    width: 100%;
    min-height: 52px;
    appearance: none;
    border: 1px solid var(--ink);
    border-radius: var(--radius-sm);
    background-color: var(--paper);
    background-image:
      linear-gradient(45deg, transparent 50%, var(--ink) 50%),
      linear-gradient(135deg, var(--ink) 50%, transparent 50%);
    background-position:
      calc(100% - 18px) calc(50% - 2px),
      calc(100% - 12px) calc(50% - 2px);
    background-repeat: no-repeat;
    background-size: 6px 6px, 6px 6px;
    padding: 0.75rem 2.4rem 0.75rem 0.85rem;
    color: var(--ink);
    font-weight: 700;
  }

  .method-fieldset {
    margin-top: 1.4rem;
  }

  .method-toggle {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .method-toggle button {
    display: grid;
    gap: 0.1rem;
    text-align: left;
  }

  .method-toggle button strong {
    font-size: 1rem;
  }

  .method-toggle button span {
    color: inherit;
    font-size: 0.76rem;
    font-weight: 500;
    opacity: 0.78;
  }

  #measurementForm {
    margin-top: 1.35rem;
  }

  .measurement-fields {
    display: grid;
    gap: 1rem;
  }

  #quickFields {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0.75rem;
  }

  .measurement-field {
    min-width: 0;
  }

  .field-heading,
  .group-heading,
  .section-heading-inline,
  .conversion-result-heading,
  .fit-plan-heading,
  .chart-heading {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
  }

  .guide-link,
  .plain-link {
    min-height: 44px;
    padding: 0.35rem 0;
    color: var(--accent-dark);
    font-size: 0.82rem;
    font-weight: 800;
    text-decoration: underline;
    text-decoration-thickness: 1px;
    text-underline-offset: 0.22em;
  }

  .guide-link:hover,
  .plain-link:hover {
    text-decoration-thickness: 2px;
  }

  .number-input-wrap {
    position: relative;
    margin-top: 0.38rem;
  }

  .number-input-wrap input {
    width: 100%;
    min-height: 62px;
    border: 1px solid var(--ink);
    border-radius: var(--radius-sm);
    background: var(--paper);
    padding: 0.65rem 3.5rem 0.65rem 0.9rem;
    color: var(--ink);
    font-family: var(--mono);
    font-size: 1.45rem;
    font-variant-numeric: tabular-nums;
    transition: border-color var(--transition-fast), background-color var(--transition-fast);
  }

  .number-input-wrap input:hover {
    border-color: var(--accent);
  }

  .number-input-wrap input[aria-invalid="true"] {
    border-width: 2px;
    border-color: var(--danger);
    background: var(--danger-soft);
  }

  .unit-suffix {
    position: absolute;
    top: 50%;
    right: 0.95rem;
    transform: translateY(-50%);
    color: var(--muted);
    font-family: var(--mono);
    font-size: 0.85rem;
    font-weight: 800;
    text-transform: uppercase;
  }

  .field-hint,
  .field-error {
    margin-top: 0.36rem;
    font-size: 0.76rem;
    line-height: 1.38;
  }

  .field-hint {
    color: var(--muted);
  }

  .field-error {
    min-height: 1.05em;
    color: var(--danger);
    font-weight: 700;
  }

  .measurement-fields--detailed {
    gap: 1.4rem;
  }

  .measurement-group {
    padding-top: 0.9rem;
    border-top: 1px solid var(--line);
  }

  .group-heading {
    margin-bottom: 0.8rem;
  }

  .measurement-grid {
    display: grid;
    gap: 0.75rem;
  }

  .measurement-grid--three {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .measurement-grid--three .number-input-wrap input {
    min-height: 56px;
    font-size: 1.15rem;
  }

  .measurement-grid--three .guide-link {
    min-height: 36px;
    font-size: 0.72rem;
  }

  .error-summary {
    margin-top: 1rem;
    border-left: 4px solid var(--danger);
    background: var(--danger-soft);
    padding: 0.9rem 1rem;
    color: var(--ink);
  }

  .error-summary ul {
    margin-top: 0.45rem;
    padding-left: 1.2rem;
  }

  .error-summary a {
    color: var(--danger);
    font-weight: 700;
  }

  .form-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.65rem;
  }

  .form-actions--primary {
    margin-top: 1.15rem;
  }

  .primary-button,
  .secondary-button {
    min-height: 52px;
    border-radius: var(--radius-sm);
    padding: 0.75rem 1rem;
    font-weight: 800;
    transition:
      background-color var(--transition-fast),
      border-color var(--transition-fast),
      color var(--transition-fast),
      transform var(--transition-fast);
  }

  .primary-button {
    border: 1px solid var(--accent-dark);
    background: var(--accent);
    color: var(--paper);
  }

  .primary-button:hover {
    background: var(--accent-dark);
  }

  .secondary-button {
    border: 1px solid var(--ink);
    background: transparent;
    color: var(--ink);
  }

  .secondary-button:hover {
    background: var(--ink);
    color: var(--paper);
  }

  .primary-button:active,
  .secondary-button:active {
    transform: translateY(1px);
  }

  .primary-button--compact,
  .secondary-button--compact {
    min-height: 44px;
    padding: 0.55rem 0.8rem;
    font-size: 0.82rem;
  }

  .primary-button:disabled,
  .secondary-button:disabled {
    cursor: not-allowed;
    opacity: 0.48;
  }

  .privacy-note {
    margin-top: 0.75rem;
    color: var(--muted);
    font-size: 0.74rem;
  }

  .privacy-note span {
    margin-right: 0.3rem;
    color: var(--success);
  }

  .ledger-rule {
    display: grid;
    height: 36px;
    grid-template-columns: repeat(10, 1fr);
    align-items: end;
    border-bottom: 1px solid var(--ink);
    background: var(--paper-deep);
  }

  .ledger-rule span {
    position: relative;
    padding-bottom: 0.22rem;
    color: var(--muted);
    font-family: var(--mono);
    font-size: 0.55rem;
    text-align: center;
  }

  .ledger-rule span::before {
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 1px;
    height: 9px;
    background: var(--ink);
    content: "";
  }

  .result-empty {
    display: grid;
    min-height: calc(min(710px, 100dvh - var(--header-height) - 3rem) - 36px);
    align-content: center;
  }

  .ledger-kicker {
    color: var(--accent);
    font-size: 0.72rem;
    font-weight: 850;
    letter-spacing: 0.13em;
    text-transform: uppercase;
  }

  .result-empty h2 {
    max-width: 11ch;
    margin-top: 0.7rem;
  }

  .result-empty > p:not(.ledger-kicker) {
    max-width: 47ch;
    margin-top: 1.25rem;
    color: var(--ink-soft);
  }

  .empty-steps {
    display: flex;
    flex-wrap: wrap;
    gap: 0.7rem 1rem;
    margin-top: 2rem;
    list-style: none;
    color: var(--muted);
    font-size: 0.85rem;
    font-weight: 700;
  }

  .empty-steps li {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
  }

  .empty-steps span {
    display: inline-grid;
    width: 1.7rem;
    height: 1.7rem;
    place-items: center;
    border: 1px solid var(--line-strong);
    border-radius: 50%;
    font-family: var(--mono);
    font-size: 0.68rem;
  }

  .result-content {
    animation: ledger-in var(--transition-panel) both;
  }

  @keyframes ledger-in {
    from {
      opacity: 0;
      transform: translateY(8px);
    }
    to {
      opacity: 1;
      transform: translateY(0);
    }
  }

  .result-heading-row {
    display: flex;
    align-items: start;
    justify-content: space-between;
    gap: 1rem;
  }

  .size-lockup {
    display: flex;
    align-items: start;
    gap: 0.55rem;
    margin-top: 0.3rem;
  }

  #primarySize {
    color: var(--ink);
    font-family: var(--serif);
    font-size: clamp(2.4rem, 3.6vw, 3.2rem);
    font-weight: 700;
    font-variant-numeric: lining-nums tabular-nums;
    letter-spacing: -0.05em;
    line-height: 0.9;
  }

  #resultSystem {
    margin-top: 0.35rem;
    color: var(--accent);
    font-size: 0.85rem;
    font-weight: 850;
    letter-spacing: 0.08em;
  }

  .result-badge {
    border: 1px solid var(--line-strong);
    border-radius: 999px;
    padding: 0.38rem 0.65rem;
    background: var(--canvas);
    color: var(--ink-soft);
    font-size: 0.68rem;
    font-weight: 800;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    white-space: nowrap;
  }

  .result-badge[data-confidence="refined"] {
    border-color: var(--success);
    background: var(--success-soft);
    color: var(--success);
  }

  .result-badge[data-confidence="check-boundary"] {
    border-color: var(--warning);
    background: var(--warning-soft);
    color: var(--warning);
  }

  .result-intro {
    max-width: 58ch;
    margin-top: 1rem;
    color: var(--ink-soft);
  }

  .result-section {
    margin-top: 1.35rem;
    padding-top: 1.05rem;
    border-top: 1px solid var(--line);
  }

  .result-section h3,
  .result-warnings h3 {
    font-family: var(--sans);
    font-size: 0.86rem;
    font-weight: 850;
    letter-spacing: 0.04em;
    text-transform: uppercase;
  }

  .size-chip-list,
  .sister-strip {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 0.7rem;
  }

  .size-chip {
    display: inline-grid;
    min-width: 4.6rem;
    min-height: 44px;
    place-items: center;
    border: 1px solid var(--ink);
    border-radius: 999px;
    background: var(--paper);
    padding: 0.5rem 0.75rem;
    color: var(--ink);
    font-family: var(--serif);
    font-size: 1.05rem;
    font-weight: 700;
  }

  button.size-chip:hover {
    background: var(--ink);
    color: var(--paper);
  }

  .calculation-trace {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0.2rem 1rem;
    margin-top: 0.65rem;
  }

  .calculation-trace div {
    display: flex;
    justify-content: space-between;
    gap: 0.75rem;
    border-bottom: 1px dotted var(--line-strong);
    padding: 0.35rem 0;
  }

  .calculation-trace dt {
    color: var(--muted);
    font-size: 0.78rem;
  }

  .calculation-trace dd {
    color: var(--ink);
    font-family: var(--mono);
    font-size: 0.78rem;
    font-weight: 700;
    font-variant-numeric: tabular-nums;
    text-align: right;
  }

  .conversion-strip {
    display: grid;
    grid-template-columns: repeat(7, minmax(0, 1fr));
    gap: 1px;
    overflow: hidden;
    margin-top: 0.7rem;
    border: 1px solid var(--line-strong);
    border-radius: var(--radius-sm);
    background: var(--line-strong);
  }

  .conversion-cell {
    min-width: 0;
    background: var(--paper);
    padding: 0.55rem 0.35rem;
    text-align: center;
  }

  .conversion-cell span {
    display: block;
    color: var(--muted);
    font-size: 0.58rem;
    font-weight: 850;
    letter-spacing: 0.06em;
    text-transform: uppercase;
  }

  .conversion-cell strong {
    display: block;
    overflow: hidden;
    margin-top: 0.2rem;
    font-family: var(--serif);
    font-size: clamp(0.82rem, 1.5vw, 1.05rem);
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  .sister-chip {
    display: grid;
    min-width: 6rem;
    border: 1px solid var(--line-strong);
    border-radius: var(--radius-sm);
    background: var(--paper-deep);
    padding: 0.5rem 0.7rem;
  }

  .sister-chip strong {
    font-family: var(--serif);
    font-size: 1.1rem;
  }

  .sister-chip span {
    color: var(--muted);
    font-size: 0.65rem;
  }

  .result-warnings {
    margin-top: 1.15rem;
    border-left: 4px solid var(--warning);
    background: var(--warning-soft);
    padding: 0.9rem 1rem;
  }

  .result-warnings ul {
    margin-top: 0.45rem;
    padding-left: 1.1rem;
    color: var(--ink-soft);
    font-size: 0.8rem;
  }

  .result-warnings li + li {
    margin-top: 0.35rem;
  }

  .result-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 1.35rem;
    padding-top: 1.1rem;
    border-top: 1px solid var(--ink);
  }

  .result-footnote,
  .conversion-caveat,
  .chart-description,
  .fieldset-help {
    color: var(--muted);
    font-size: 0.78rem;
    line-height: 1.5;
  }

  .result-footnote {
    margin-top: 0.85rem;
  }

  .conversion-result-heading,
  .fit-plan-heading {
    align-items: start;
  }

  .conversion-result-heading h3,
  .section-heading-inline--top h3,
  .fit-plan-heading h3 {
    margin-top: 0.25rem;
    font-family: var(--serif);
    font-size: clamp(1.6rem, 3vw, 2.4rem);
  }

  .mode-result-actions {
    display: flex;
    flex-wrap: wrap;
    justify-content: flex-end;
    gap: 0.6rem;
  }

  .conversion-result-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 1px;
    overflow: hidden;
    margin-top: 1.4rem;
    border: 1px solid var(--ink);
    background: var(--ink);
  }

  .conversion-result-item {
    min-height: 96px;
    background: var(--paper);
    padding: 0.85rem;
  }

  .conversion-result-item.is-source {
    background: var(--accent);
    color: var(--paper);
  }

  .conversion-result-item span {
    display: block;
    color: inherit;
    font-size: 0.67rem;
    font-weight: 850;
    letter-spacing: 0.06em;
    opacity: 0.72;
    text-transform: uppercase;
  }

  .conversion-result-item strong {
    display: block;
    margin-top: 0.25rem;
    font-family: var(--serif);
    font-size: 1.55rem;
    line-height: 1;
  }

  .conversion-result-item small {
    display: block;
    margin-top: 0.35rem;
    color: inherit;
    font-size: 0.62rem;
    opacity: 0.7;
  }

  .conversion-caveat {
    margin-top: 1rem;
  }

  .chart-ledger {
    overflow: hidden;
    border: 2px solid var(--ink);
    border-radius: var(--radius-lg);
    background: var(--paper);
  }

  .chart-ledger--inline {
    border-width: 1px;
    border-radius: 0;
  }

  .chart-heading {
    padding: 1.25rem 1.4rem;
    border-bottom: 1px solid var(--ink);
    background: var(--paper-deep);
  }

  .chart-heading h3 {
    margin-top: 0.25rem;
    font-family: var(--serif);
    font-size: clamp(1.4rem, 2.5vw, 2rem);
  }

  .chart-heading--controls {
    align-items: end;
  }

  .chart-controls {
    display: flex;
    flex: 1 1 auto;
    flex-wrap: wrap;
    align-items: end;
    justify-content: flex-end;
    gap: 0.7rem;
  }

  .chart-controls .select-field--compact {
    max-width: 180px;
  }

  .inline-choice {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: flex-end;
    gap: 0.5rem 1rem;
  }

  .inline-choice legend {
    width: 100%;
    text-align: right;
  }

  .inline-choice label,
  .radio-row {
    display: inline-flex;
    min-height: 44px;
    align-items: center;
    gap: 0.45rem;
    color: var(--ink-soft);
    font-size: 0.8rem;
    font-weight: 700;
  }

  input[type="checkbox"],
  input[type="radio"] {
    width: 1.15rem;
    height: 1.15rem;
    flex: 0 0 auto;
    accent-color: var(--accent);
  }

  .table-scroll {
    max-width: 100%;
    overflow: auto;
    scrollbar-gutter: stable;
  }

  .table-scroll--large {
    max-height: min(68vh, 760px);
  }

  .data-table {
    width: 100%;
    min-width: 720px;
    background: var(--paper);
    font-size: 0.82rem;
    font-variant-numeric: tabular-nums;
  }

  .data-table caption {
    padding: 0.85rem 1rem;
    color: var(--muted);
    font-size: 0.75rem;
    text-align: left;
  }

  .data-table thead th {
    position: sticky;
    z-index: 2;
    top: 0;
    border-bottom: 2px solid var(--ink);
    background: var(--ink);
    color: var(--paper);
    font-size: 0.68rem;
    letter-spacing: 0.06em;
    text-transform: uppercase;
  }

  .data-table th,
  .data-table td {
    border-right: 1px solid var(--line);
    border-bottom: 1px solid var(--line);
    padding: 0.7rem 0.8rem;
    text-align: left;
    white-space: nowrap;
  }

  .data-table th:last-child,
  .data-table td:last-child {
    border-right: 0;
  }

  .data-table tbody th {
    position: sticky;
    z-index: 1;
    left: 0;
    background: var(--paper-deep);
    font-family: var(--serif);
    font-size: 1rem;
  }

  .data-table tbody tr:nth-child(even) td {
    background: #faf6ef;
  }

  .data-table tbody tr:hover td,
  .data-table tbody tr:hover th {
    background: var(--accent-soft);
  }

  .data-table .is-current {
    background: var(--accent-soft) !important;
    color: var(--accent-dark);
    font-weight: 850;
  }

  .sister-matrix {
    display: grid;
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 1px;
    overflow: hidden;
    margin-top: 1.25rem;
    border: 1px solid var(--ink);
    background: var(--ink);
  }

  .sister-matrix-item {
    position: relative;
    display: grid;
    min-height: 145px;
    align-content: center;
    justify-items: center;
    background: var(--paper);
    padding: 1rem 0.7rem;
    text-align: center;
  }

  .sister-matrix-item.is-current {
    background: var(--accent);
    color: var(--paper);
  }

  .sister-matrix-item strong {
    font-family: var(--serif);
    font-size: clamp(1.45rem, 3vw, 2.1rem);
  }

  .sister-matrix-item span {
    margin-top: 0.35rem;
    color: inherit;
    font-size: 0.68rem;
    font-weight: 800;
    opacity: 0.72;
  }

  .sister-matrix-item small {
    margin-top: 0.55rem;
    color: inherit;
    font-size: 0.64rem;
    opacity: 0.65;
  }

  .sister-explanation {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1rem;
    margin-top: 1rem;
    color: var(--ink-soft);
    font-size: 0.82rem;
  }

  .fit-block {
    padding: clamp(1.3rem, 3vw, 2rem);
  }

  .fit-block + .fit-block {
    border-top: 1px solid var(--ink);
  }

  .fit-size-selects {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr 0.8fr;
    gap: 0.65rem;
    margin-top: 0.8rem;
  }

  .fieldset-help {
    margin-top: 0.65rem;
  }

  .radio-row {
    width: 100%;
    border-bottom: 1px solid var(--line);
  }

  .fit-symptom-column > legend {
    margin-bottom: 0.85rem;
  }

  .symptom-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    border-top: 1px solid var(--line);
    border-left: 1px solid var(--line);
  }

  .symptom-option {
    display: flex;
    min-height: 86px;
    align-items: start;
    gap: 0.7rem;
    border-right: 1px solid var(--line);
    border-bottom: 1px solid var(--line);
    background: var(--paper);
    padding: 0.9rem;
    cursor: pointer;
    transition: background-color var(--transition-fast);
  }

  .symptom-option:hover {
    background: var(--paper-deep);
  }

  .symptom-option:has(input:checked) {
    background: var(--accent-soft);
  }

  .symptom-option input {
    margin-top: 0.1rem;
  }

  .symptom-option span {
    display: grid;
    gap: 0.2rem;
  }

  .symptom-option strong {
    font-size: 0.86rem;
    line-height: 1.2;
  }

  .symptom-option small {
    font-size: 0.7rem;
    line-height: 1.35;
  }

  .fit-form-error {
    margin-block: 0.65rem;
  }

  .fit-step-list {
    display: grid;
    margin-top: 1.4rem;
    border-top: 1px solid var(--ink);
    list-style: none;
    counter-reset: fit-step;
  }

  .fit-step {
    display: grid;
    grid-template-columns: 3rem minmax(0, 1fr) minmax(130px, auto);
    gap: 1rem;
    border-bottom: 1px solid var(--line);
    padding-block: 1.2rem;
    counter-increment: fit-step;
  }

  .fit-step::before {
    content: counter(fit-step, decimal-leading-zero);
    color: var(--accent);
    font-family: var(--mono);
    font-size: 0.78rem;
    font-weight: 850;
  }

  .fit-step-copy h4 {
    font-family: var(--serif);
    font-size: 1.25rem;
    line-height: 1.2;
  }

  .fit-step-copy p {
    margin-top: 0.45rem;
    color: var(--ink-soft);
    font-size: 0.86rem;
  }

  .fit-step-copy small {
    display: block;
    margin-top: 0.45rem;
    font-size: 0.7rem;
  }

  .fit-target {
    display: grid;
    align-content: center;
    justify-items: end;
    gap: 0.3rem;
  }

  .fit-target strong {
    font-family: var(--serif);
    font-size: 1.75rem;
  }

  .fit-target span {
    color: var(--muted);
    font-size: 0.65rem;
    font-weight: 800;
    letter-spacing: 0.06em;
    text-transform: uppercase;
  }

  .fit-target button {
    margin-top: 0.3rem;
  }

  .medical-boundary {
    margin-top: 1.3rem;
    border-left: 4px solid var(--accent);
    background: var(--accent-soft);
    padding: 1rem;
    color: var(--ink-soft);
    font-size: 0.8rem;
  }

  .chart-description {
    padding: 0.9rem 1.4rem;
    border-bottom: 1px solid var(--line);
  }

  .reference-block {
    display: grid;
    grid-template-columns: 3.5rem minmax(0, 1fr);
    gap: 1.2rem;
    border-bottom: 1px solid var(--ink);
    padding-block: clamp(1.5rem, 4vw, 2.5rem);
  }

  .reference-number {
    color: var(--accent);
    font-family: var(--mono);
    font-size: 0.75rem;
    font-weight: 850;
  }

  .reference-block h3 {
    font-family: var(--serif);
    font-size: clamp(1.35rem, 2.5vw, 1.9rem);
  }

  .reference-block p {
    max-width: 67ch;
    margin-top: 0.75rem;
    color: var(--ink-soft);
  }

  .reference-block .plain-link {
    margin-top: 0.65rem;
  }

  .update-notice {
    position: fixed;
    z-index: 60;
    right: max(1rem, env(safe-area-inset-right));
    bottom: max(1rem, env(safe-area-inset-bottom));
    display: grid;
    max-width: min(420px, calc(100% - 2rem));
    grid-template-columns: minmax(0, 1fr) auto auto;
    align-items: center;
    gap: 0.8rem;
    border: 2px solid var(--ink);
    border-radius: var(--radius);
    background: var(--paper);
    padding: 0.9rem;
  }

  .update-notice p {
    color: var(--muted);
    font-size: 0.75rem;
  }

  .site-dialog {
    width: min(920px, calc(100% - 2rem));
    max-height: min(90dvh, 900px);
    overflow: hidden;
    border: 2px solid var(--ink);
    border-radius: var(--radius-lg);
    background: var(--paper);
    color: var(--ink);
    padding: 0;
  }

  .site-dialog::backdrop {
    background: rgba(33, 26, 24, 0.74);
    backdrop-filter: blur(4px);
  }

  .dialog-shell {
    display: grid;
    max-height: min(90dvh, 900px);
    grid-template-rows: auto minmax(0, 1fr) auto;
  }

  .dialog-shell--small {
    max-width: 560px;
    margin-inline: auto;
  }

  .dialog-header,
  .dialog-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    padding: 1.15rem 1.35rem;
  }

  .dialog-header {
    border-bottom: 1px solid var(--ink);
    background: var(--paper-deep);
  }

  .dialog-header h2 {
    margin-top: 0.25rem;
    font-size: clamp(1.65rem, 4vw, 2.6rem);
  }

  .dialog-footer {
    justify-content: flex-end;
    border-top: 1px solid var(--ink);
    background: var(--paper-deep);
  }

  .guide-tabs {
    display: flex;
    overflow-x: auto;
    border-bottom: 1px solid var(--line);
    background: var(--paper);
  }

  .guide-tabs button {
    min-width: max-content;
    min-height: 48px;
    border-right: 1px solid var(--line);
    background: transparent;
    padding: 0.6rem 1rem;
    color: var(--muted);
    font-size: 0.78rem;
    font-weight: 800;
  }

  .guide-tabs button[aria-selected="true"] {
    background: var(--ink);
    color: var(--paper);
  }

  .guide-content {
    display: grid;
    min-height: 0;
    grid-template-columns: minmax(250px, 0.9fr) minmax(0, 1.1fr);
    overflow: auto;
  }

  .guide-illustration {
    display: grid;
    place-items: center;
    border-right: 1px solid var(--ink);
    background: var(--canvas);
    padding: clamp(1rem, 4vw, 2.5rem);
  }

  .measurement-illustration {
    width: min(100%, 420px);
  }

  .guide-paper {
    fill: var(--paper);
    stroke: var(--ink);
    stroke-width: 2;
  }

  .guide-grid {
    fill: none;
    stroke: var(--line);
    stroke-width: 0.65;
    opacity: 0.48;
  }

  .guide-body {
    fill: var(--paper-deep);
    stroke: var(--ink);
    stroke-width: 3;
    stroke-linejoin: round;
  }

  .guide-body-detail,
  .guide-floor,
  .guide-level {
    fill: none;
    stroke: var(--ink-soft);
    stroke-width: 1.6;
    stroke-linecap: round;
  }

  .guide-tape {
    fill: none;
    stroke: var(--accent);
    stroke-width: 4;
  }

  .guide-tape--tight {
    stroke-width: 6;
  }

  .guide-tape--loose {
    stroke-dasharray: 4 3;
  }

  .guide-tape-ticks {
    fill: none;
    stroke: var(--accent);
    stroke-width: 1.1;
  }

  .guide-level-dot {
    fill: var(--accent);
  }

  .guide-copy {
    align-self: center;
    padding: clamp(1.4rem, 4vw, 3rem);
  }

  .guide-copy h3 {
    margin-top: 0.35rem;
    font-family: var(--serif);
    font-size: clamp(1.6rem, 3vw, 2.35rem);
  }

  .guide-copy > p:not(.ledger-kicker) {
    margin-top: 0.8rem;
    color: var(--ink-soft);
  }

  .guide-copy ul {
    margin-top: 1rem;
    padding-left: 1.2rem;
    color: var(--muted);
    font-size: 0.84rem;
  }

  .guide-copy li + li {
    margin-top: 0.45rem;
  }

  .reading-content {
    min-height: 0;
    overflow: auto;
    padding: clamp(1.4rem, 4vw, 2.8rem);
  }

  .reading-content section + section {
    margin-top: 1.8rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--line);
  }

  .reading-content h3 {
    font-family: var(--serif);
    font-size: 1.5rem;
  }

  .reading-content p {
    max-width: 75ch;
    margin-top: 0.75rem;
    color: var(--ink-soft);
  }

  .source-list {
    display: grid;
    gap: 0.55rem;
    margin-top: 0.9rem;
    padding-left: 1.2rem;
  }

  .source-list a {
    overflow-wrap: anywhere;
  }

  .method-note {
    margin-top: 1.8rem;
    border-left: 4px solid var(--accent);
    background: var(--accent-soft);
    padding: 1rem;
  }

  .method-note p {
    margin-top: 0.35rem;
  }

  .legal-columns {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: clamp(1.5rem, 4vw, 3rem);
  }

  .legal-columns section + section {
    margin-top: 0;
    border-top: 0;
    border-left: 1px solid var(--line);
    padding-top: 0;
    padding-left: clamp(1.5rem, 4vw, 3rem);
  }

  .inline-status {
    min-height: 1.2em;
    color: var(--success);
    font-size: 0.78rem;
  }

  .shortcut-list {
    display: grid;
    overflow: auto;
    padding: 1.2rem 1.35rem;
  }

  .shortcut-list div {
    display: grid;
    grid-template-columns: 3rem minmax(0, 1fr);
    align-items: center;
    gap: 1rem;
    border-bottom: 1px solid var(--line);
    padding-block: 0.6rem;
  }

  .dialog-shell--small > p {
    padding: 0 1.35rem 1.2rem;
    color: var(--muted);
    font-size: 0.8rem;
  }

  .noscript-message {
    position: fixed;
    z-index: 100;
    right: 1rem;
    bottom: 1rem;
    left: 1rem;
    border: 2px solid var(--danger);
    background: var(--danger-soft);
    padding: 1rem;
    color: var(--ink);
    font-weight: 700;
    text-align: center;
  }
}

@layer utilities {
  .sr-only {
    position: absolute !important;
    width: 1px !important;
    height: 1px !important;
    overflow: hidden !important;
    clip: rect(0, 0, 0, 0) !important;
    white-space: nowrap !important;
    clip-path: inset(50%) !important;
  }

  .is-busy {
    cursor: wait;
  }

  .is-busy button,
  .is-busy input,
  .is-busy select {
    pointer-events: none;
  }
}

@layer responsive {
  @media (min-width: 901px) {
    .measure-input-pane h1 {
      max-width: 15ch;
      font-size: clamp(3.1rem, 4vw, 3.9rem);
    }

    .measure-input-pane .lede {
      margin-top: 0.85rem;
      font-size: 1.02rem;
      line-height: 1.45;
    }

    .measure-input-pane .control-row--preferences {
      margin-top: 1rem;
      padding-block: 0.75rem;
    }

    .measure-input-pane .method-fieldset,
    .measure-input-pane #measurementForm {
      margin-top: 0.9rem;
    }
  }

  @media (max-width: 1080px) {
    .header-inner {
      grid-template-columns: minmax(170px, 1fr) minmax(0, auto) auto;
      gap: 0.7rem;
    }

    .brand-copy span,
    .print-header-button {
      display: none;
    }

    .mode-button {
      padding-inline: 0.65rem;
      font-size: 0.78rem;
    }

    .measure-workbench {
      grid-template-columns: minmax(0, 1fr) minmax(390px, 1.15fr);
      gap: 1.25rem;
    }

    .conversion-strip {
      grid-template-columns: repeat(4, minmax(0, 1fr));
    }

    .conversion-result-grid {
      grid-template-columns: repeat(3, minmax(0, 1fr));
    }

    .sister-matrix {
      grid-template-columns: repeat(3, minmax(0, 1fr));
    }

    .sister-matrix-item:nth-child(4),
    .sister-matrix-item:nth-child(5) {
      min-height: 115px;
    }
  }

  @media (max-width: 900px) {
    :root {
      --header-height: 116px;
    }

    .site-header {
      position: sticky;
    }

    .header-inner {
      grid-template-columns: 1fr auto;
      grid-template-rows: 62px 54px;
      gap: 0;
    }

    .brand {
      grid-column: 1;
    }

    .header-actions {
      grid-column: 2;
    }

    .mode-nav {
      grid-column: 1 / -1;
      grid-row: 2;
      width: calc(100% + (var(--page-pad) * 2));
      margin-left: calc(var(--page-pad) * -1);
      overflow-x: auto;
      justify-content: start;
      border-top: 1px solid var(--line-strong);
      padding-inline: var(--page-pad);
      scrollbar-width: none;
    }

    .mode-nav::-webkit-scrollbar {
      display: none;
    }

    .mode-button {
      flex: 0 0 auto;
    }

    .measure-workbench {
      min-height: 0;
      grid-template-columns: 1fr;
    }

    .result-ledger {
      position: relative;
      top: auto;
      min-height: 560px;
    }

    .result-empty {
      min-height: 520px;
    }

    .mode-workbench--converter,
    .mode-workbench--sister,
    .fit-workbench {
      grid-template-columns: 1fr;
    }

    .size-entry-form,
    .fit-size-column {
      border-right: 0;
      border-bottom: 1px solid var(--ink);
    }

    .fit-size-column {
      display: grid;
      grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .fit-block + .fit-block {
      border-top: 0;
      border-left: 1px solid var(--ink);
    }

    .reference-content,
    .trust-band {
      grid-template-columns: 1fr;
      gap: 2rem;
    }

    .reference-intro {
      position: static;
    }

    .chart-heading--controls {
      align-items: start;
      flex-direction: column;
    }

    .chart-controls {
      width: 100%;
      justify-content: start;
    }
  }

  @media (max-width: 680px) {
    :root {
      --page-pad: 1rem;
    }

    body::before {
      background-size: 36px 36px;
      opacity: 0.22;
    }

    .brand-copy strong {
      font-size: 1rem;
    }

    .tool-stage {
      padding-top: 1rem;
    }

    .measure-input-pane {
      padding-top: 0;
    }

    h1 {
      font-size: clamp(2.6rem, 14vw, 4.15rem);
    }

    h2 {
      font-size: clamp(2rem, 10vw, 3rem);
    }

    .control-row--preferences {
      align-items: stretch;
    }

    .compact-fieldset,
    .select-field--compact {
      flex-basis: 100%;
    }

    #quickFields,
    .measurement-grid--three {
      grid-template-columns: 1fr;
    }

    .measurement-group {
      padding-top: 1.1rem;
    }

    .measurement-grid--three .number-input-wrap input {
      min-height: 60px;
      font-size: 1.35rem;
    }

    .result-ledger {
      min-height: 520px;
      border-radius: var(--radius);
    }

    .result-empty {
      min-height: 480px;
    }

    .result-empty,
    .result-content {
      padding: 1.25rem;
    }

    #primarySize {
      font-size: clamp(2.8rem, 12vw, 3.8rem);
    }

    .result-heading-row {
      align-items: start;
      flex-direction: column-reverse;
    }

    .calculation-trace {
      grid-template-columns: 1fr;
    }

    .conversion-strip {
      grid-template-columns: repeat(3, minmax(0, 1fr));
    }

    .result-actions > * {
      flex: 1 1 45%;
    }

    .size-entry-form {
      grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .size-entry-form .select-field:first-child,
    .size-entry-form .primary-button {
      grid-column: 1 / -1;
    }

    .conversion-result-heading,
    .section-heading-inline--top,
    .fit-plan-heading,
    .chart-heading {
      align-items: start;
      flex-direction: column;
    }

    .mode-result-actions {
      justify-content: start;
    }

    .conversion-result-grid {
      grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .inline-choice {
      justify-content: start;
    }

    .inline-choice legend {
      text-align: left;
    }

    .sister-matrix {
      grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .sister-matrix-item.is-current {
      grid-column: 1 / -1;
      grid-row: 1;
    }

    .sister-explanation,
    .fit-size-column,
    .legal-columns {
      grid-template-columns: 1fr;
    }

    .fit-block + .fit-block,
    .legal-columns section + section {
      border-top: 1px solid var(--ink);
      border-left: 0;
      padding-top: 1.4rem;
      padding-left: 0;
    }

    .fit-size-selects {
      grid-template-columns: 1fr 1fr;
    }

    .fit-size-selects .select-field:first-child {
      grid-column: 1 / -1;
    }

    .symptom-grid {
      grid-template-columns: 1fr;
    }

    .fit-step {
      grid-template-columns: 2.5rem minmax(0, 1fr);
    }

    .fit-target {
      grid-column: 2;
      justify-items: start;
      border-left: 3px solid var(--accent);
      padding-left: 0.8rem;
    }

    .chart-controls .select-field--compact {
      max-width: none;
      flex-basis: calc(50% - 0.7rem);
    }

    .reference-block {
      grid-template-columns: 2.5rem minmax(0, 1fr);
    }

    .footer-inner {
      grid-template-columns: 1fr;
    }

    .footer-inner nav {
      justify-content: start;
    }

    .update-notice {
      left: max(1rem, env(safe-area-inset-left));
      grid-template-columns: minmax(0, 1fr) auto;
    }

    .update-notice .icon-button {
      position: absolute;
      top: -14px;
      right: -10px;
      width: 36px;
      height: 36px;
      flex-basis: 36px;
      background: var(--paper);
    }

    .guide-content {
      grid-template-columns: 1fr;
    }

    .guide-illustration {
      border-right: 0;
      border-bottom: 1px solid var(--ink);
    }

    .guide-tabs button {
      padding-inline: 0.8rem;
    }
  }

  @media (max-width: 430px) {
    .brand-copy span {
      display: none;
    }

    .header-actions .text-button {
      display: none;
    }

    .method-toggle button {
      padding-inline: 0.7rem;
    }

    .form-actions--primary > * {
      width: 100%;
    }

    .conversion-strip {
      grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .result-actions > * {
      flex-basis: 100%;
    }

    .size-entry-form {
      grid-template-columns: 1fr;
    }

    .size-entry-form .select-field:first-child,
    .size-entry-form .primary-button {
      grid-column: auto;
    }

    .conversion-result-grid {
      grid-template-columns: 1fr 1fr;
    }

    .chart-controls .select-field--compact {
      flex-basis: 100%;
    }
  }

  @media (prefers-reduced-motion: reduce) {
    html {
      scroll-behavior: auto;
    }

    *,
    *::before,
    *::after {
      scroll-behavior: auto !important;
      animation-duration: 0.01ms !important;
      animation-iteration-count: 1 !important;
      transition-duration: 0.01ms !important;
    }
  }

  @media (forced-colors: active) {
    :root {
      --canvas: Canvas;
      --paper: Canvas;
      --paper-deep: Canvas;
      --ink: CanvasText;
      --ink-soft: CanvasText;
      --muted: CanvasText;
      --line: CanvasText;
      --line-strong: CanvasText;
      --accent: Highlight;
      --accent-dark: LinkText;
      --accent-soft: Canvas;
      --success: CanvasText;
      --success-soft: Canvas;
      --warning: CanvasText;
      --warning-soft: Canvas;
      --danger: CanvasText;
      --danger-soft: Canvas;
      --focus: Highlight;
    }

    body::before {
      display: none;
    }

    .privacy-dot,
    .guide-level-dot {
      forced-color-adjust: none;
      background: Highlight;
      fill: Highlight;
    }

    .primary-button,
    .mode-button.is-active,
    .segmented button[aria-pressed="true"],
    .guide-tabs button[aria-selected="true"] {
      border: 2px solid ButtonText;
      background: Highlight;
      color: HighlightText;
    }

    .symptom-option:has(input:checked),
    .result-badge,
    .result-warnings,
    .medical-boundary,
    .method-note {
      border: 2px solid CanvasText;
    }
  }
}

@layer print {
  @media print {
    @page {
      size: auto;
      margin: 12mm;
    }

    :root {
      --canvas: #fff;
      --paper: #fff;
      --paper-deep: #fff;
      --ink: #000;
      --ink-soft: #222;
      --muted: #444;
      --line: #aaa;
      --line-strong: #555;
      --accent: #000;
      --accent-dark: #000;
      --accent-soft: #fff;
      --warning-soft: #fff;
      --danger-soft: #fff;
      --success-soft: #fff;
    }

    html,
    body {
      background: #fff !important;
      color: #000 !important;
      font-size: 10pt;
    }

    body::before,
    .site-header,
    .reference-content,
    .trust-band,
    .site-footer,
    .update-notice,
    dialog,
    .noscript-message,
    .result-actions,
    .guide-link,
    .plain-link,
    .chart-controls button,
    .mode-result-actions {
      display: none !important;
    }

    .tool-stage {
      width: 100%;
      padding: 0;
    }

    [data-mode-panel] {
      display: none !important;
    }

    body[data-print-scope="result"] #measurePanel,
    body[data-print-scope="fit"] #fitPanel,
    body[data-print-scope="chart"] #chartsPanel,
    body[data-print-scope="conversion"] #convertPanel,
    body[data-print-scope="sister"] #sisterPanel {
      display: block !important;
    }

    body[data-print-scope="result"] .measure-input-pane,
    body[data-print-scope="fit"] .mode-intro,
    body[data-print-scope="fit"] .fit-workbench,
    body[data-print-scope="chart"] .mode-intro,
    body[data-print-scope="conversion"] .mode-intro,
    body[data-print-scope="conversion"] .size-entry-form,
    body[data-print-scope="sister"] .mode-intro,
    body[data-print-scope="sister"] .size-entry-form {
      display: none !important;
    }

    .measure-workbench,
    .mode-layout,
    .mode-workbench,
    .fit-plan,
    .chart-ledger {
      display: block;
      min-height: 0;
      border: 0;
      box-shadow: none;
    }

    .result-ledger {
      position: static;
      display: block;
      min-height: 0;
      border: 1px solid #000;
      break-inside: avoid;
    }

    .result-content,
    .conversion-result,
    .sister-result,
    .fit-plan,
    .chart-heading {
      padding: 8mm;
    }

    .ledger-rule {
      display: none;
    }

    #primarySize {
      font-size: 36pt;
    }

    .conversion-strip,
    .conversion-result-grid,
    .sister-matrix {
      border-color: #000;
      background: #000;
    }

    .conversion-cell,
    .conversion-result-item,
    .sister-matrix-item,
    .sister-matrix-item.is-current,
    .conversion-result-item.is-source {
      background: #fff !important;
      color: #000 !important;
    }

    .result-warnings,
    .medical-boundary {
      background: #fff;
      border: 1px solid #000;
    }

    .fit-plan[hidden] {
      display: none !important;
    }

    .fit-step-list,
    .fit-step {
      break-inside: avoid;
    }

    .chart-controls .select-field {
      display: none;
    }

    .table-scroll,
    .table-scroll--large {
      max-height: none;
      overflow: visible;
    }

    .data-table {
      min-width: 0;
      font-size: 8pt;
    }

    .data-table thead th,
    .data-table tbody th {
      position: static;
      background: #fff !important;
      color: #000 !important;
    }

    .data-table th,
    .data-table td {
      padding: 4pt 5pt;
      border: 1px solid #777;
    }

    a {
      color: #000;
      text-decoration: none;
    }
  }
}

@layer components {
  .viz3d-card {
    margin-top: 1rem;
  }

  .viz3d-card--primary {
    margin-top: 1.1rem;
  }

  .viz3d-card--bare {
    margin-top: 0;
  }

  .viz3d-views {
    display: flex;
    gap: 0.3rem;
  }

  .viz3d-views--floating {
    justify-content: flex-end;
    margin-bottom: 0.55rem;
  }

  .viz3d-view-button {
    min-height: 36px;
    padding: 0.25rem 0.75rem;
    border: 1px solid var(--line-strong);
    border-radius: var(--radius-sm);
    background: var(--paper);
    color: var(--ink-soft);
    font: inherit;
    font-size: 0.82rem;
    cursor: pointer;
  }

  .viz3d-view-button:hover {
    color: var(--ink);
    border-color: var(--ink);
  }

  .viz3d-view-button.is-active {
    background: var(--ink);
    border-color: var(--ink);
    color: var(--paper);
  }

  .viz3d-view-button:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
  }

  .viz3d-view-button:disabled {
    opacity: 0.45;
    cursor: not-allowed;
  }

  .viz3d-stage {
    position: relative;
    width: 100%;
    aspect-ratio: 5 / 3;
    min-height: 230px;
    margin-top: 0.7rem;
    border: 1px solid var(--line);
    border-radius: var(--radius-sm);
    background:
      radial-gradient(115% 90% at 50% 8%, var(--paper) 55%, var(--paper-deep) 100%);
    overflow: hidden;
    cursor: grab;
    touch-action: none;
  }

  .viz3d-stage:active {
    cursor: grabbing;
  }

  .viz3d-stage:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
  }

  .viz3d-stage--tall {
    aspect-ratio: 1 / 1;
    min-height: 320px;
  }

  .viz3d-canvas {
    display: block;
    width: 100% !important;
    height: 100% !important;
    touch-action: none;
  }

  [data-viz-state="fallback"] .viz3d-stage {
    display: none;
  }

  .viz3d-fallback {
    margin-top: 0.7rem;
    padding: 0.8rem 0.9rem;
    border: 1px dashed var(--line-strong);
    border-radius: var(--radius-sm);
    color: var(--ink-soft);
    font-size: 0.88rem;
  }

  .viz3d-caption {
    margin-top: 0.55rem;
    color: var(--muted);
    font-size: 0.84rem;
    line-height: 1.5;
  }

  .viz3d-explorer .explorer-layout {
    display: grid;
    grid-template-columns: minmax(0, 7fr) minmax(250px, 5fr);
    gap: 1.4rem;
    align-items: start;
    margin-top: 0.9rem;
  }

  .explorer-controls {
    display: grid;
    gap: 0.9rem;
  }

  .explorer-stepper {
    margin: 0;
    padding: 0.7rem 0.9rem 0.85rem;
    border: 1px solid var(--line);
    border-radius: var(--radius-sm);
    background: var(--paper);
  }

  .explorer-stepper legend {
    padding: 0 0.3rem;
    color: var(--muted);
    font-size: 0.78rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
  }

  .stepper-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.8rem;
  }

  .stepper-button {
    min-width: 44px;
    min-height: 44px;
    border: 1px solid var(--line-strong);
    border-radius: var(--radius-sm);
    background: var(--paper);
    color: var(--ink);
    font-size: 1.25rem;
    line-height: 1;
    cursor: pointer;
  }

  .stepper-button:hover:not(:disabled) {
    border-color: var(--accent);
    color: var(--accent);
  }

  .stepper-button:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
  }

  .stepper-button:disabled {
    opacity: 0.4;
    cursor: not-allowed;
  }

  .stepper-value {
    font-family: Georgia, "Times New Roman", Times, serif;
    font-size: 1.7rem;
    color: var(--ink);
  }

  .explorer-facts {
    color: var(--ink-soft);
    font-size: 0.88rem;
    line-height: 1.55;
  }

  .conversion-strip--explorer {
    margin-top: 0;
  }
}

@layer responsive {
  @media (max-width: 900px) {
    .viz3d-explorer .explorer-layout {
      grid-template-columns: 1fr;
    }
  }

  @media (max-width: 720px) {
    .viz3d-view-button {
      min-height: 44px;
    }

    .viz3d-stage {
      min-height: 230px;
    }

    .conversion-strip--explorer {
      grid-template-columns: repeat(4, minmax(0, 1fr));
    }
  }

  @media (forced-colors: active) {
    .viz3d-stage,
    .viz3d-views {
      display: none;
    }

    .viz3d-fallback[hidden] {
      display: block;
    }
  }
}

@layer print {
  @media print {
    .viz3d-card,
    .viz3d-explorer {
      display: none !important;
    }
  }
}