@layer tokens, base, layout, components, utilities;

/* Top-level opt-in for intrinsic keyword transitions (Chrome/Edge progressive enhancement) */
:root {
  interpolate-size: allow-keywords;
}

@layer tokens {
  :root {
    /* Tier 1: Literal Palette (Anthropic / Claude Editorial Warmth + Subtle Botanical Sage) */
    --stone-50: #faf9f5;
    --stone-100: #f3f1ea;
    --stone-150: #ebe8de;
    --stone-200: #e3dfd3;
    --stone-300: #d1ccc0;
    --stone-500: #6b6860;
    --stone-600: #524f49;
    --stone-800: #262522;
    --stone-900: #141413;

    --clay-50: #f9efe9;
    --clay-100: #f2ddd1;
    --clay-500: #c96442;
    --clay-600: #b35232;
    --clay-700: #934024;

    --sage-50: #edf2ee;
    --sage-100: #dce6df;
    --sage-600: #3a604e;
    --sage-700: #2a483a;

    --danger-50: #fcebe8;
    --danger-600: #b8332a;

    --white: #ffffff;

    /* Typography Tokens */
    --font-serif: 'Newsreader', 'Source Serif 4', Georgia, 'Times New Roman', serif;
    --font-sans: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace;

    /* Tier 2: Semantic Tokens */
    --bg-canvas: var(--stone-50);
    --bg-subtle: var(--stone-100);
    --bg-muted: var(--stone-150);
    --bg-surface: var(--white);
    --bg-inverse: var(--stone-900);
    --bg-inverse-elevated: var(--stone-800);

    --text-primary: var(--stone-900);
    --text-secondary: var(--stone-600);
    --text-muted: var(--stone-500);
    --text-inverse: var(--stone-50);
    --text-inverse-muted: #b9b5aa;

    --accent-primary: var(--clay-500);
    --accent-primary-hover: var(--clay-600);
    --accent-subtle: var(--clay-50);
    --accent-border: var(--clay-100);

    --accent-botanical: var(--sage-600);
    --accent-botanical-subtle: var(--sage-50);
    --accent-botanical-border: var(--sage-100);

    /* Tier 3: UI Tokens */
    --border-hairline: var(--stone-200);
    --border-strong: var(--stone-300);
    --border-inverse: #35332f;

    --radius-sm: 0.5rem;
    --radius-md: 0.75rem;
    --radius-lg: 1.125rem;
    --radius-xl: 1.5rem;
    --radius-pill: 999rem;

    --shadow-card: 0 1px 2px rgba(20, 20, 19, 0.04), 0 8px 24px rgba(20, 20, 19, 0.035);
    --shadow-elevated: 0 2px 6px rgba(20, 20, 19, 0.05), 0 20px 48px rgba(20, 20, 19, 0.07);

    --space-xs: 0.5rem;
    --space-sm: 0.75rem;
    --space-md: 1.25rem;
    --space-lg: 2rem;
    --space-xl: 3.5rem;
    --space-2xl: clamp(4.5rem, 3.2rem + 4vw, 7rem);

    --container-max: 74rem;
    --header-height: 4.5rem;
  }
}

@layer base {
  :where(
    html, body, header, nav, main, section, article, aside, footer,
    div, p, h1, h2, h3, h4, ul, ol, li, dl, dt, dd, figure, figcaption,
    form, fieldset, legend, label, input, select, textarea, button, a,
    details, summary, span, small, strong, em, svg
  ) {
    box-sizing: border-box;
  }

  html {
    scroll-behavior: smooth;
    scroll-padding-block-start: calc(var(--header-height) + 1.5rem);
    color-scheme: light;
    -webkit-text-size-adjust: 100%;
  }

  body {
    margin: 0;
    background-color: var(--bg-canvas);
    color: var(--text-primary);
    font-family: var(--font-sans);
    font-size: 1rem;
    line-height: 1.6;
    text-align: start;
    overflow-wrap: break-word;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
  }

  :where(h1, h2, h3, h4) {
    margin-block: 0;
    font-family: var(--font-serif);
    font-weight: 400;
    line-height: 1.14;
    letter-spacing: -0.022em;
    color: inherit;
    text-wrap: balance;
  }

  h1 {
    font-size: clamp(2.5rem, 1.75rem + 3.2vw, 4.25rem);
    line-height: 1.08;
    letter-spacing: -0.028em;
  }

  h2 {
    font-size: clamp(1.95rem, 1.45rem + 2.1vw, 3rem);
  }

  h3 {
    font-size: clamp(1.3rem, 1.15rem + 0.5vw, 1.55rem);
    line-height: 1.24;
  }

  :where(h1, h2, h3) em {
    font-style: italic;
    color: var(--accent-primary);
  }

  :where(p, ul, ol, dl, figure, blockquote) {
    margin-block: 0;
  }

  :where(button, input, select, textarea) {
    font: inherit;
    color: inherit;
  }

  a {
    color: inherit;
    text-decoration: none;
  }

  button {
    cursor: pointer;
    background: transparent;
    border: 0;
  }

  :where(a, button, summary, input, select, textarea):focus-visible {
    outline: 2px solid var(--accent-primary);
    outline-offset: 3px;
  }

  ::selection {
    background-color: var(--clay-100);
    color: var(--stone-900);
  }
}

@layer layout {
  .container {
    inline-size: min(var(--container-max), calc(100% - 3rem));
    margin-inline: auto;
  }

  .section {
    padding-block: var(--space-2xl);
    border-block-end: 1px solid var(--border-hairline);
  }

  .section-subtle {
    background-color: var(--bg-subtle);
  }

  .section-header {
    display: grid;
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.8fr);
    gap: clamp(1.5rem, 4vw, 4rem);
    align-items: end;
    margin-block-end: clamp(2.5rem, 4vw, 3.75rem);
  }

  .section-lead {
    color: var(--text-secondary);
    font-size: 1.0625rem;
    line-height: 1.68;
    max-inline-size: 56ch;
    text-wrap: pretty;
  }

  .prose p {
    color: var(--text-secondary);
    font-size: 1.0625rem;
    line-height: 1.72;
    max-inline-size: 64ch;
    text-wrap: pretty;
  }

  .prose p:not(:last-child) {
    margin-block-end: 1.15rem;
  }

  @media (max-width: 56rem) {
    .section-header {
      grid-template-columns: 1fr;
      align-items: start;
      gap: 1rem;
    }
  }

  @media (max-width: 40rem) {
    .container {
      inline-size: calc(100% - 2rem);
    }
  }
}

@layer components {
  /* Skip Link */
  .skip-link {
    position: fixed;
    inset-block-start: -10rem;
    inset-inline-start: 1rem;
    z-index: 100;
    padding: 0.75rem 1.25rem;
    background-color: var(--bg-inverse);
    color: var(--text-inverse);
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-weight: 600;
  }

  .skip-link:focus {
    inset-block-start: 1rem;
  }

  /* Top Editorial Note Bar */
  .top-banner {
    background-color: var(--bg-subtle);
    border-block-end: 1px solid var(--border-hairline);
    padding-block: 0.625rem;
    padding-inline: 1rem;
    text-align: center;
    font-size: 0.8125rem;
    color: var(--text-secondary);
  }

  .top-banner a {
    color: var(--text-primary);
    font-weight: 600;
    margin-inline-start: 0.5rem;
    text-decoration: underline;
    text-decoration-color: var(--border-strong);
    text-underline-offset: 0.22em;
    transition: text-decoration-color 0.2s ease, color 0.2s ease;
  }

  .top-banner a:hover {
    color: var(--accent-primary);
    text-decoration-color: currentColor;
  }

  /* Sticky Header */
  .site-header {
    position: sticky;
    inset-block-start: 0;
    z-index: 40;
    background-color: rgba(250, 249, 245, 0.88);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    border-block-end: 1px solid var(--border-hairline);
  }

  .nav-bar {
    min-block-size: var(--header-height);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1.5rem;
  }

  .brand {
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    flex-shrink: 0;
  }

  .brand-mark {
    inline-size: 2.125rem;
    block-size: 2.125rem;
    border-radius: 0.625rem;
    background-color: var(--bg-inverse);
    color: var(--stone-50);
    display: grid;
    place-items: center;
    flex-shrink: 0;
  }

  .brand-text {
    display: flex;
    flex-direction: column;
    line-height: 1.15;
  }

  .brand-name {
    font-family: var(--font-serif);
    font-size: 1.1875rem;
    font-weight: 500;
    letter-spacing: -0.015em;
  }

  .brand-sub {
    font-family: var(--font-mono);
    font-size: 0.6875rem;
    color: var(--text-muted);
    letter-spacing: 0.04em;
  }

  .nav-links {
    display: flex;
    align-items: center;
    gap: 1.75rem;
    list-style: none;
    padding: 0;
    margin-inline-start: auto;
  }

  .nav-links a {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
    padding-block: 0.375rem;
    transition: color 0.18s ease;
  }

  .nav-links a:hover {
    color: var(--text-primary);
  }

  .nav-actions {
    display: flex;
    align-items: center;
    gap: 0.75rem;
  }

  .menu-toggle {
    display: none;
    inline-size: 2.75rem;
    block-size: 2.75rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-hairline);
    background-color: var(--bg-surface);
    align-items: center;
    justify-content: center;
    color: var(--text-primary);
  }

  /* Buttons */
  .btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.55rem;
    min-block-size: 2.875rem;
    padding-block: 0.65rem;
    padding-inline: 1.3rem;
    border-radius: var(--radius-md);
    corner-shape: squircle;
    font-size: 0.9375rem;
    font-weight: 600;
    line-height: 1.2;
    border: 1px solid transparent;
    transition: background-color 0.18s ease, border-color 0.18s ease, color 0.18s ease, transform 0.18s ease;
  }

  .btn:hover:not(:disabled) {
    transform: translateY(-1px);
  }

  .btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
  }

  .btn-primary {
    background-color: var(--accent-primary);
    color: var(--white);
  }

  .btn-primary:hover:not(:disabled) {
    background-color: var(--accent-primary-hover);
  }

  .btn-dark {
    background-color: var(--bg-inverse);
    color: var(--text-inverse);
  }

  .btn-dark:hover:not(:disabled) {
    background-color: var(--stone-800);
  }

  .btn-secondary {
    background-color: var(--bg-surface);
    color: var(--text-primary);
    border-color: var(--border-strong);
  }

  .btn-secondary:hover:not(:disabled) {
    background-color: var(--bg-subtle);
    border-color: var(--text-primary);
  }

  .btn-ghost-light {
    background-color: rgba(255, 255, 255, 0.08);
    color: var(--text-inverse);
    border-color: rgba(255, 255, 255, 0.2);
  }

  .btn-ghost-light:hover:not(:disabled) {
    background-color: rgba(255, 255, 255, 0.15);
    border-color: rgba(255, 255, 255, 0.35);
  }

  .btn-sm {
    min-block-size: 2.375rem;
    padding-block: 0.45rem;
    padding-inline: 1rem;
    font-size: 0.875rem;
  }

  .btn-full {
    inline-size: 100%;
  }

  /* Eyebrows & Badges */
  .eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-family: var(--font-mono);
    font-size: 0.78125rem;
    font-weight: 500;
    color: var(--text-muted);
    margin-block-end: 1rem;
  }

  .eyebrow-dot {
    inline-size: 0.45rem;
    block-size: 0.45rem;
    border-radius: 50%;
    background-color: var(--accent-primary);
  }

  .eyebrow-light {
    color: var(--clay-100);
  }

  /* Hero Section */
  .hero {
    padding-block-start: clamp(3rem, 5vw, 5.25rem);
    padding-block-end: clamp(3.5rem, 5vw, 5.5rem);
    border-block-end: 1px solid var(--border-hairline);
  }

  .hero-grid {
    display: grid;
    grid-template-columns: minmax(0, 1.08fr) minmax(0, 0.92fr);
    gap: clamp(2.5rem, 5vw, 4.5rem);
    align-items: center;
  }

  .hero-copy h1 {
    margin-block-end: 1.35rem;
  }

  .hero-lead {
    font-size: clamp(1.0625rem, 1rem + 0.3vw, 1.2rem);
    line-height: 1.65;
    color: var(--text-secondary);
    max-inline-size: 52ch;
    text-wrap: pretty;
    margin-block-end: 2rem;
  }

  .hero-actions {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.875rem;
    margin-block-end: 2.5rem;
  }

  .hero-trust {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1rem;
    padding-block-start: 1.5rem;
    border-block-start: 1px solid var(--border-hairline);
  }

  .trust-item strong {
    display: block;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-block-end: 0.2rem;
  }

  .trust-item span {
    font-size: 0.8125rem;
    color: var(--text-muted);
    line-height: 1.45;
  }

  /* Claude Artifact-Inspired Architectural Preview Card in Hero */
  .artifact-card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-hairline);
    border-radius: var(--radius-xl);
    corner-shape: squircle;
    box-shadow: var(--shadow-elevated);
    overflow: hidden;
  }

  .artifact-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
    padding: 0.875rem 1.25rem;
    background-color: var(--bg-subtle);
    border-block-end: 1px solid var(--border-hairline);
  }

  .artifact-title {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-secondary);
  }

  .artifact-tag {
    font-family: var(--font-mono);
    font-size: 0.6875rem;
    padding: 0.2rem 0.55rem;
    border-radius: var(--radius-pill);
    background-color: var(--accent-botanical-subtle);
    color: var(--accent-botanical);
    border: 1px solid var(--accent-botanical-border);
  }

  .artifact-canvas {
    padding: clamp(1.35rem, 3vw, 2rem);
    background:
      radial-gradient(circle at 88% 12%, var(--clay-50) 0%, transparent 52%),
      radial-gradient(circle at 12% 90%, var(--sage-50) 0%, transparent 48%),
      var(--bg-surface);
  }

  .artifact-illustration {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1.25rem;
    padding: 1.25rem;
    border-radius: var(--radius-lg);
    background-color: var(--bg-canvas);
    border: 1px solid var(--border-hairline);
    margin-block-end: 1.25rem;
  }

  .artifact-quote p {
    font-family: var(--font-serif);
    font-size: 1.3rem;
    line-height: 1.28;
    color: var(--text-primary);
    margin-block-end: 0.35rem;
  }

  .artifact-quote small {
    font-size: 0.8125rem;
    color: var(--text-muted);
  }

  .artifact-svg {
    inline-size: 5.5rem;
    block-size: 5.5rem;
    flex-shrink: 0;
  }

  .pillar-list {
    list-style: none;
    padding: 0;
    display: grid;
    gap: 0.625rem;
  }

  .pillar-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    padding: 0.75rem 1rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-hairline);
    background-color: var(--bg-surface);
    font-size: 0.875rem;
  }

  .pillar-item strong {
    font-weight: 600;
    color: var(--text-primary);
  }

  .pillar-meta {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-muted);
  }

  .artifact-footer {
    padding: 0.875rem 1.25rem;
    border-block-start: 1px solid var(--border-hairline);
    background-color: var(--bg-canvas);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    font-size: 0.8125rem;
    color: var(--text-secondary);
  }

  .artifact-footer a {
    font-weight: 600;
    color: var(--accent-primary);
  }

  .artifact-footer a:hover {
    text-decoration: underline;
    text-underline-offset: 0.2em;
  }

  /* Perspective / Comparison Section */
  .perspective-grid {
    display: grid;
    grid-template-columns: minmax(0, 0.95fr) minmax(0, 1.05fr);
    gap: clamp(2rem, 5vw, 4.5rem);
    align-items: start;
  }

  .comparison-card {
    margin-block-start: 2rem;
    background-color: var(--bg-subtle);
    border: 1px solid var(--border-hairline);
    border-radius: var(--radius-lg);
    overflow: hidden;
  }

  .comparison-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
  }

  .comparison-row:not(:last-child) {
    border-block-end: 1px solid var(--border-hairline);
  }

  .comparison-cell {
    padding: 1.125rem 1.25rem;
    font-size: 0.875rem;
    line-height: 1.55;
  }

  .comparison-cell:first-child {
    color: var(--text-muted);
    border-inline-end: 1px solid var(--border-hairline);
  }

  .comparison-cell:last-child {
    background-color: var(--bg-surface);
    color: var(--text-primary);
    font-weight: 500;
  }

  .comparison-head .comparison-cell {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    padding-block: 0.75rem;
    background-color: var(--bg-muted);
    color: var(--text-secondary);
  }

  .comparison-head .comparison-cell:last-child {
    background-color: var(--accent-subtle);
    color: var(--clay-700);
  }

  .inline-link {
    display: inline-flex;
    align-items: center;
    gap: 0.45rem;
    margin-block-start: 1.5rem;
    font-size: 0.9375rem;
    font-weight: 600;
    color: var(--accent-primary);
    border-block-end: 1px solid var(--accent-border);
    padding-block-end: 0.25rem;
    transition: border-color 0.2s ease, gap 0.2s ease;
  }

  .inline-link:hover {
    border-color: currentColor;
    gap: 0.65rem;
  }

  /* 4-Card Benefits Bento Grid */
  .benefit-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1.25rem;
  }

  .benefit-card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-hairline);
    border-radius: var(--radius-lg);
    corner-shape: squircle;
    padding: clamp(1.5rem, 2.5vw, 2rem);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    gap: 1.5rem;
    box-shadow: var(--shadow-card);
    transition: border-color 0.2s ease, transform 0.2s ease;
  }

  .benefit-card:hover {
    border-color: var(--border-strong);
    transform: translateY(-2px);
  }

  .benefit-top {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 1rem;
  }

  .card-index {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-muted);
    padding: 0.25rem 0.6rem;
    border-radius: var(--radius-sm);
    background-color: var(--bg-subtle);
    border: 1px solid var(--border-hairline);
  }

  .benefit-icon {
    inline-size: 3.25rem;
    block-size: 3.25rem;
    border-radius: var(--radius-md);
    background-color: var(--bg-canvas);
    border: 1px solid var(--border-hairline);
    display: grid;
    place-items: center;
    flex-shrink: 0;
  }

  .benefit-body h3 {
    margin-block-end: 0.65rem;
  }

  .benefit-body p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.68;
    max-inline-size: 52ch;
    text-wrap: pretty;
  }

  .footnote-banner {
    margin-block-start: 1.5rem;
    padding: 0.95rem 1.25rem;
    border-radius: var(--radius-md);
    background-color: var(--bg-canvas);
    border: 1px solid var(--border-hairline);
    font-size: 0.8125rem;
    color: var(--text-muted);
    line-height: 1.6;
  }

  /* Warm Charcoal Editorial Callout Band */
  .editorial-band {
    padding-block: var(--space-2xl);
    border-block-end: 1px solid var(--border-hairline);
  }

  .band-panel {
    background-color: var(--bg-inverse);
    color: var(--text-inverse);
    border-radius: var(--radius-xl);
    corner-shape: squircle;
    padding: clamp(2.25rem, 5vw, 4.25rem);
    display: grid;
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    gap: clamp(2rem, 4vw, 3.5rem);
    align-items: center;
  }

  .band-panel h2 em {
    color: var(--clay-100);
  }

  .band-panel p {
    color: var(--text-inverse-muted);
    font-size: 1.0625rem;
    line-height: 1.7;
    max-inline-size: 48ch;
    margin-block: 1.25rem 2rem;
    text-wrap: pretty;
  }

  .diagram-card {
    background-color: var(--bg-inverse-elevated);
    border: 1px solid var(--border-inverse);
    border-radius: var(--radius-lg);
    padding: 1.75rem;
  }

  .diagram-label {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-inverse-muted);
    display: block;
    margin-block-end: 1.15rem;
  }

  .equation-stack {
    display: grid;
    gap: 0.65rem;
    margin-block-end: 1.25rem;
  }

  .equation-node {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.8rem 1rem;
    border-radius: var(--radius-md);
    background-color: rgba(255, 255, 255, 0.04);
    border: 1px solid var(--border-inverse);
    font-family: var(--font-serif);
    font-size: 1.25rem;
  }

  .equation-node span:last-child {
    font-family: var(--font-sans);
    font-size: 0.8125rem;
    color: var(--text-inverse-muted);
  }

  .diagram-card small {
    display: block;
    font-size: 0.8125rem;
    color: var(--text-inverse-muted);
    line-height: 1.5;
  }

  /* How It Works — 3-Step Architectural Grid */
  .steps-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    border: 1px solid var(--border-hairline);
    border-radius: var(--radius-lg);
    background-color: var(--bg-surface);
    overflow: hidden;
  }

  .step-card {
    padding: clamp(1.5rem, 3vw, 2.25rem);
    display: flex;
    flex-direction: column;
    gap: 1rem;
  }

  .step-card:not(:last-child) {
    border-inline-end: 1px solid var(--border-hairline);
  }

  .step-number {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    inline-size: 2.25rem;
    block-size: 2.25rem;
    border-radius: var(--radius-sm);
    background-color: var(--accent-subtle);
    color: var(--clay-700);
    font-family: var(--font-mono);
    font-size: 0.8125rem;
    font-weight: 600;
  }

  .step-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.68;
    text-wrap: pretty;
  }

  .step-meta {
    margin-block-start: auto;
    padding-block-start: 1rem;
    border-block-start: 1px solid var(--border-hairline);
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-muted);
  }

  /* Interactive Scenario Planner (Claude Artifact Style) */
  .calculator-grid {
    display: grid;
    grid-template-columns: minmax(0, 0.88fr) minmax(0, 1.12fr);
    gap: clamp(2rem, 4.5vw, 4rem);
    align-items: start;
  }

  .compliance-callout {
    margin-block-start: 1.75rem;
    padding: 1.125rem 1.25rem;
    border-inline-start: 3px solid var(--accent-primary);
    background-color: var(--bg-surface);
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
    font-size: 0.8125rem;
    line-height: 1.65;
    color: var(--text-secondary);
  }

  .compliance-callout strong {
    display: block;
    color: var(--text-primary);
    margin-block-end: 0.25rem;
  }

  .planner-card {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-hairline);
    border-radius: var(--radius-xl);
    corner-shape: squircle;
    box-shadow: var(--shadow-elevated);
    overflow: hidden;
  }

  .planner-header {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
    padding: 1.125rem 1.75rem;
    background-color: var(--bg-canvas);
    border-block-end: 1px solid var(--border-hairline);
  }

  .planner-header h3 {
    font-size: 1.25rem;
  }

  .preset-group {
    display: flex;
    align-items: center;
    gap: 0.375rem;
  }

  .preset-chip {
    padding: 0.3rem 0.65rem;
    border-radius: var(--radius-pill);
    border: 1px solid var(--border-hairline);
    background-color: var(--bg-surface);
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-secondary);
    transition: background-color 0.15s ease, border-color 0.15s ease, color 0.15s ease;
  }

  .preset-chip:hover {
    border-color: var(--border-strong);
    color: var(--text-primary);
  }

  .preset-chip[aria-pressed='true'] {
    background-color: var(--bg-inverse);
    border-color: var(--bg-inverse);
    color: var(--text-inverse);
  }

  .planner-body {
    padding: clamp(1.5rem, 3vw, 2rem);
    display: grid;
    gap: 1.5rem;
  }

  .control-block {
    display: grid;
    gap: 0.5rem;
  }

  .control-header {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 1rem;
  }

  .control-header label {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-primary);
  }

  .control-readout {
    font-family: var(--font-mono);
    font-size: 1.25rem;
    font-weight: 600;
    font-variant-numeric: tabular-nums;
    color: var(--text-primary);
  }

  .control-readout small {
    font-family: var(--font-sans);
    font-size: 0.8125rem;
    font-weight: 400;
    color: var(--text-muted);
    margin-inline-start: 0.25rem;
  }

  input[type='range'] {
    inline-size: 100%;
    min-block-size: 2.25rem;
    accent-color: var(--accent-primary);
    cursor: pointer;
    margin: 0;
  }

  .range-scale {
    display: flex;
    justify-content: space-between;
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-muted);
  }

  /* Accessible Radio Pill Group (<= 5 options per Modern Web Guidance) */
  .radio-fieldset {
    border: 0;
    padding: 0;
    margin: 0;
  }

  .radio-fieldset legend {
    padding: 0;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-block-end: 0.65rem;
  }

  .radio-pills {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 0.5rem;
  }

  .radio-pills-wrap {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
  }

  .radio-pill {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    min-block-size: 3rem;
    padding: 0.6rem 0.85rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-strong);
    background-color: var(--bg-canvas);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    text-align: center;
    transition: background-color 0.15s ease, border-color 0.15s ease, color 0.15s ease;
  }

  .radio-pill:hover {
    border-color: var(--text-primary);
    color: var(--text-primary);
  }

  .radio-pill:has(input:checked) {
    background-color: var(--accent-subtle);
    border-color: var(--accent-primary);
    color: var(--clay-700);
    font-weight: 600;
  }

  .radio-pill:has(input:focus-visible) {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
  }

  .visually-hidden {
    position: absolute;
    clip-path: inset(50%);
    overflow: hidden;
    inline-size: 1px;
    block-size: 1px;
    margin: -1px;
    padding: 0;
    border: 0;
    white-space: nowrap;
  }

  .result-panel {
    background-color: var(--accent-botanical-subtle);
    border: 1px solid var(--accent-botanical-border);
    border-radius: var(--radius-lg);
    padding: 1.35rem;
  }

  .result-metrics {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.75rem;
    padding-block-end: 1rem;
    margin-block-end: 1rem;
    border-block-end: 1px solid var(--accent-botanical-border);
  }

  .metric-mini span {
    display: block;
    font-size: 0.75rem;
    color: var(--text-secondary);
  }

  .metric-mini strong {
    font-family: var(--font-mono);
    font-size: 1rem;
    font-variant-numeric: tabular-nums;
    color: var(--text-primary);
  }

  .result-primary {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 1rem;
    flex-wrap: wrap;
  }

  .result-primary span {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--sage-700);
    max-inline-size: 28ch;
  }

  .result-primary output {
    font-family: var(--font-serif);
    font-size: clamp(2rem, 1.6rem + 1.2vw, 2.5rem);
    font-weight: 500;
    font-variant-numeric: tabular-nums;
    color: var(--sage-700);
    line-height: 1;
  }

  .result-note {
    display: block;
    margin-block-start: 0.75rem;
    font-size: 0.78125rem;
    color: var(--text-secondary);
    line-height: 1.5;
  }

  .planner-footnote {
    font-size: 0.75rem;
    color: var(--text-muted);
    line-height: 1.6;
  }

  /* Share Card + FAQ Section */
  .faq-grid {
    display: grid;
    grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
    gap: clamp(2rem, 5vw, 4.5rem);
    align-items: start;
  }

  .share-box {
    margin-block-start: 2rem;
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    background-color: var(--bg-subtle);
    border: 1px solid var(--border-hairline);
  }

  .share-box h3 {
    font-size: 1.2rem;
    margin-block-end: 0.45rem;
  }

  .share-box p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-block-end: 1.15rem;
  }

  .share-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.625rem;
  }

  .share-status {
    display: block;
    min-block-size: 1.25rem;
    margin-block-start: 0.65rem;
    font-size: 0.8125rem;
    font-weight: 500;
    color: var(--accent-botanical);
  }

  /* Native Exclusive Accordion (<details name="faq">) */
  .faq-list {
    border-block-start: 1px solid var(--border-hairline);
  }

  .faq-item {
    border-block-end: 1px solid var(--border-hairline);
  }

  .faq-item summary {
    list-style: none;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1.25rem;
    padding-block: 1.3rem;
    font-family: var(--font-serif);
    font-size: 1.225rem;
    line-height: 1.32;
    color: var(--text-primary);
    cursor: pointer;
    transition: color 0.18s ease;
  }

  .faq-item summary::-webkit-details-marker {
    display: none;
  }

  .faq-item summary:hover {
    color: var(--accent-primary);
  }

  .faq-icon {
    inline-size: 1.75rem;
    block-size: 1.75rem;
    border-radius: 50%;
    border: 1px solid var(--border-hairline);
    background-color: var(--bg-surface);
    display: grid;
    place-items: center;
    flex-shrink: 0;
    color: var(--text-secondary);
    transition: transform 0.25s ease, background-color 0.2s ease, border-color 0.2s ease;
  }

  .faq-item[open] .faq-icon {
    transform: rotate(45deg);
    background-color: var(--accent-subtle);
    border-color: var(--accent-border);
    color: var(--accent-primary);
  }

  .faq-item::details-content {
    block-size: 0;
    overflow: hidden;
    transition: block-size 0.28s ease, content-visibility 0.28s ease allow-discrete;
  }

  .faq-item[open]::details-content {
    block-size: auto;
  }

  .faq-answer {
    padding-block-end: 1.4rem;
    padding-inline-end: 2.5rem;
  }

  .faq-answer p {
    color: var(--text-secondary);
    font-size: 0.96875rem;
    line-height: 1.72;
    max-inline-size: 62ch;
    text-wrap: pretty;
  }

  /* Contact Section & Production Form */
  .contact-grid {
    display: grid;
    grid-template-columns: minmax(0, 0.88fr) minmax(0, 1.12fr);
    gap: clamp(2rem, 5vw, 4.5rem);
    align-items: start;
  }

  .contact-highlights {
    list-style: none;
    padding: 0;
    margin-block-start: 2rem;
    display: grid;
    gap: 1rem;
  }

  .contact-highlights li {
    display: flex;
    align-items: flex-start;
    gap: 0.85rem;
    padding: 1rem 1.15rem;
    border-radius: var(--radius-md);
    background-color: var(--bg-surface);
    border: 1px solid var(--border-hairline);
  }

  .highlight-badge {
    inline-size: 2rem;
    block-size: 2rem;
    border-radius: var(--radius-sm);
    background-color: var(--accent-subtle);
    color: var(--accent-primary);
    display: grid;
    place-items: center;
    flex-shrink: 0;
  }

  .contact-highlights strong {
    display: block;
    font-size: 0.9rem;
    margin-block-end: 0.15rem;
  }

  .contact-highlights span {
    font-size: 0.84375rem;
    color: var(--text-secondary);
    line-height: 1.5;
  }

  .lead-form {
    background-color: var(--bg-surface);
    border: 1px solid var(--border-hairline);
    border-radius: var(--radius-xl);
    corner-shape: squircle;
    padding: clamp(1.5rem, 3.5vw, 2.5rem);
    box-shadow: var(--shadow-elevated);
  }

  .form-head {
    padding-block-end: 1.35rem;
    margin-block-end: 1.5rem;
    border-block-end: 1px solid var(--border-hairline);
  }

  .form-head h3 {
    font-size: 1.45rem;
    margin-block-end: 0.25rem;
  }

  .form-head p {
    font-size: 0.875rem;
    color: var(--text-muted);
  }

  /* Gestalt Proximity: Tighter spacing inside .field, larger gap between .field groups */
  .field {
    margin-block-end: 1.35rem;
  }

  .field-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
  }

  .field label {
    display: block;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-block-end: 0.35rem;
  }

  .required-mark {
    color: var(--accent-primary);
    margin-inline-start: 0.15rem;
  }

  .field-hint {
    display: block;
    font-size: 0.8125rem;
    color: var(--text-muted);
    margin-block-end: 0.4rem;
  }

  .lead-form :where(input:not([type='checkbox'], [type='radio']), select, textarea) {
    inline-size: 100%;
    min-block-size: 3rem;
    padding: 0.75rem 0.95rem;
    font-size: 1rem;
    line-height: 1.4;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-strong);
    background-color: var(--bg-canvas);
    color: var(--text-primary);
    transition: border-color 0.15s ease, background-color 0.15s ease, box-shadow 0.15s ease;
  }

  .lead-form textarea {
    min-block-size: 5.5rem;
    resize: vertical;
  }

  .lead-form :where(input:not([type='checkbox'], [type='radio']), select, textarea):focus {
    background-color: var(--bg-surface);
    border-color: var(--accent-primary);
  }

  /* Post-interaction Validation (:user-invalid + WeakMap JS fallback) */
  .lead-form :is(input, select, textarea):where(:user-invalid, .user-invalid-fallback) {
    border-color: var(--danger-600);
    background-color: var(--danger-50);
  }

  .lead-form :is(input:not([type='checkbox'], [type='radio']), textarea):where(:user-valid, .user-valid-fallback) {
    border-color: var(--accent-botanical);
  }

  .error-msg {
    display: none;
    margin-block-start: 0.375rem;
    font-size: 0.8125rem;
    font-weight: 500;
    color: var(--danger-600);
  }

  .lead-form :is(input, select, textarea):where(:user-invalid, .user-invalid-fallback) + .error-msg {
    display: block;
  }

  .consent-field {
    margin-block: 1.25rem 1.5rem;
  }

  .consent-label {
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    font-size: 0.84375rem;
    font-weight: 400;
    line-height: 1.55;
    color: var(--text-secondary);
    cursor: pointer;
  }

  .consent-label input[type='checkbox'] {
    inline-size: 1.15rem;
    block-size: 1.15rem;
    margin-block-start: 0.18rem;
    accent-color: var(--accent-primary);
    flex-shrink: 0;
  }

  .consent-field:has(input:where(:user-invalid, .user-invalid-fallback)) .error-msg {
    display: block;
  }

  .form-confirmation {
    margin-block-start: 1.15rem;
    padding: 1.15rem 1.25rem;
    border-radius: var(--radius-md);
    background-color: var(--accent-botanical-subtle);
    border: 1px solid var(--accent-botanical-border);
    color: var(--sage-700);
    font-size: 0.875rem;
    line-height: 1.6;
  }

  .form-confirmation[hidden] {
    display: none;
  }

  .form-confirmation strong {
    display: block;
    margin-block-end: 0.25rem;
    font-size: 0.9375rem;
  }

  .form-privacy-note {
    display: block;
    margin-block-start: 0.95rem;
    font-size: 0.75rem;
    color: var(--text-muted);
    line-height: 1.55;
  }

  /* Footer */
  .site-footer {
    background-color: var(--bg-inverse);
    color: var(--text-inverse);
    padding-block: 3.75rem 2.5rem;
  }

  .footer-top {
    display: flex;
    flex-wrap: wrap;
    align-items: flex-start;
    justify-content: space-between;
    gap: 2.5rem;
    padding-block-end: 2.5rem;
    border-block-end: 1px solid var(--border-inverse);
  }

  .footer-brand .brand-mark {
    background-color: var(--stone-50);
    color: var(--stone-900);
  }

  .footer-brand p {
    margin-block-start: 0.85rem;
    color: var(--text-inverse-muted);
    font-size: 0.9rem;
    max-inline-size: 36ch;
  }

  .footer-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 1.5rem 2rem;
    list-style: none;
    padding: 0;
  }

  .footer-nav a {
    font-size: 0.875rem;
    color: var(--text-inverse-muted);
    transition: color 0.18s ease;
  }

  .footer-nav a:hover {
    color: var(--text-inverse);
  }

  .footer-bottom {
    padding-block-start: 1.75rem;
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    font-size: 0.8125rem;
    color: var(--text-inverse-muted);
  }

  .footer-bottom a {
    color: var(--text-inverse);
    font-weight: 500;
  }

  /* Coarse Pointer Ergonomics */
  @media (pointer: coarse) {
    .lead-form :where(input:not([type='checkbox'], [type='radio']), select, textarea),
    .radio-pill {
      min-block-size: 3.25rem;
    }
  }

  /* Responsive Breakpoints */
  @media (max-width: 60rem) {
    .hero-grid,
    .perspective-grid,
    .band-panel,
    .calculator-grid,
    .faq-grid,
    .contact-grid {
      grid-template-columns: 1fr;
    }

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

    .step-card:not(:last-child) {
      border-inline-end: 0;
      border-block-end: 1px solid var(--border-hairline);
    }
  }

  @media (max-width: 50rem) {
    .menu-toggle {
      display: inline-flex;
    }

    .nav-cta-desktop {
      display: none;
    }

    .nav-links {
      display: none;
      position: absolute;
      inset-block-start: 100%;
      inset-inline: 0;
      flex-direction: column;
      align-items: stretch;
      gap: 0.25rem;
      padding: 1rem 1.5rem 1.35rem;
      background-color: var(--bg-canvas);
      border-block-end: 1px solid var(--border-hairline);
      box-shadow: var(--shadow-elevated);
    }

    .nav-links.is-open {
      display: flex;
    }

    .nav-links a {
      display: block;
      padding: 0.75rem 0.5rem;
      font-size: 1rem;
      color: var(--text-primary);
    }

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

    .hero-trust {
      grid-template-columns: 1fr;
      gap: 0.85rem;
    }
  }

  @media (max-width: 36rem) {
    .radio-pills {
      grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .field-row,
    .result-metrics,
    .comparison-row {
      grid-template-columns: 1fr;
    }

    .comparison-cell:first-child {
      border-inline-end: 0;
      border-block-end: 1px solid var(--border-hairline);
    }

    .artifact-illustration {
      flex-direction: column;
      align-items: flex-start;
    }
  }
}

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

    :where(.btn, .benefit-card, .faq-icon, .faq-item::details-content, .inline-link) {
      transition: none !important;
    }
  }
}