:root {
      --bg: oklch(8% 0.006 260);
      --surface: oklch(13% 0.006 260);
      --surface-2: oklch(18% 0.007 260);
      --fg: oklch(96% 0.003 260);
      --muted: oklch(70% 0.006 260);
      --subtle: oklch(54% 0.006 260);
      --border: oklch(28% 0.006 260);
      --accent: oklch(87% 0.006 260);
      --danger: oklch(66% 0.14 25);
      --success: oklch(77% 0.12 155);
      --photo-warm: oklch(68% 0.055 65);
      --font-display: 'Iowan Old Style', 'Charter', Georgia, serif;
      --font-body: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
      --font-mono: 'JetBrains Mono', 'IBM Plex Mono', ui-monospace, Menlo, monospace;
      --max: 1180px;
      --pad: clamp(18px, 3.4vw, 56px);
    }

    * { box-sizing: border-box; }
    html { scroll-behavior: smooth; }
    body {
      margin: 0;
      background:
        radial-gradient(circle at 80% 6%, color-mix(in oklch, var(--photo-warm) 18%, transparent), transparent 28rem),
        linear-gradient(180deg, oklch(7% 0.005 260), var(--bg) 36rem, oklch(10% 0.006 260));
      color: var(--fg);
      font-family: var(--font-body);
      line-height: 1.45;
      -webkit-font-smoothing: antialiased;
      text-rendering: optimizeLegibility;
    }

    a { color: inherit; text-decoration: none; }
    button, input, select, textarea { font: inherit; }
    img { max-width: 100%; display: block; }

    .site-shell { min-height: 100vh; overflow: clip; }
    .noise {
      position: fixed;
      inset: 0;
      pointer-events: none;
      opacity: 0.08;
      mix-blend-mode: screen;
      background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.74' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='200' height='200' filter='url(%23n)' opacity='.9'/%3E%3C/svg%3E");
      z-index: 10;
    }

    .nav {
      position: fixed;
      top: 18px;
      left: 50%;
      transform: translateX(-50%);
      width: min(calc(100% - 28px), 1040px);
      z-index: 20;
      display: grid;
      grid-template-columns: auto 1fr auto;
      align-items: center;
      gap: 20px;
      padding: 9px 10px 9px 18px;
      border: 1px solid color-mix(in oklch, var(--fg) 13%, transparent);
      background: color-mix(in oklch, var(--bg) 74%, transparent);
      backdrop-filter: blur(18px);
      -webkit-backdrop-filter: blur(18px);
      border-radius: 999px;
      box-shadow: 0 18px 80px rgba(0, 0, 0, 0.28);
    }

    .brand {
      font-family: var(--font-mono);
      font-size: 12px;
      letter-spacing: 0.16em;
      text-transform: uppercase;
      white-space: nowrap;
    }

    .nav-links {
      display: flex;
      justify-content: center;
      gap: clamp(12px, 2vw, 26px);
      color: var(--muted);
      font-size: 14px;
    }

    .nav-cta,
    .btn {
      border: 1px solid var(--fg);
      background: var(--fg);
      color: var(--bg);
      min-height: 44px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 9px;
      padding: 0 18px;
      border-radius: 999px;
      font-weight: 700;
      cursor: pointer;
      transition: transform 200ms cubic-bezier(0.23, 1, 0.32, 1), background 200ms cubic-bezier(0.23, 1, 0.32, 1), color 200ms cubic-bezier(0.23, 1, 0.32, 1);
      white-space: nowrap;
    }

    .btn:hover, .nav-cta:hover { transform: translateY(-2px); }
    .btn.secondary {
      background: transparent;
      color: var(--fg);
      border-color: color-mix(in oklch, var(--fg) 35%, transparent);
    }

    .hero {
      min-height: 100svh;
      position: relative;
      display: grid;
      align-items: end;
      padding: 112px var(--pad) 42px;
      isolation: isolate;
    }

    .hero::before {
      content: "";
      position: absolute;
      inset: 0;
      background:
        linear-gradient(90deg, rgba(0, 0, 0, 0.82) 0%, rgba(0, 0, 0, 0.48) 45%, rgba(0, 0, 0, 0.2) 100%),
        linear-gradient(0deg, var(--bg) 0%, transparent 34%),
        url("/resources/math-tutor/images/hero-portrait.jpg") center / cover no-repeat;
      z-index: -3;
    }

    .hero::after {
      content: "∫ f(x) dx  ·  x² + y² = r²  ·  P(A|B)";
      position: absolute;
      right: -26px;
      top: 24%;
      writing-mode: vertical-rl;
      color: color-mix(in oklch, var(--fg) 18%, transparent);
      font-family: var(--font-mono);
      font-size: 12px;
      letter-spacing: 0.32em;
      z-index: -1;
    }

    .hero-inner {
      width: min(100%, 1420px);
      margin: 0 auto;
      display: grid;
      grid-template-columns: minmax(0, 1.05fr) minmax(280px, 0.45fr);
      gap: clamp(28px, 5vw, 92px);
      align-items: end;
    }

    .kicker {
      font-family: var(--font-mono);
      font-size: 12px;
      text-transform: uppercase;
      letter-spacing: 0.22em;
      color: var(--muted);
      margin-bottom: 22px;
    }

    h1, h2, h3, p { margin: 0; }
    h1 {
      max-width: 980px;
      font-family: var(--font-display);
      font-weight: 500;
      font-size: clamp(58px, 9.8vw, 152px);
      line-height: 0.9;
      letter-spacing: 0;
      text-wrap: balance;
    }

    .hero-copy {
      max-width: 660px;
      margin-top: 26px;
      color: color-mix(in oklch, var(--fg) 84%, transparent);
      font-size: clamp(18px, 2vw, 24px);
      text-wrap: pretty;
    }

    .hero-actions {
      display: flex;
      flex-wrap: wrap;
      gap: 12px;
      margin-top: 34px;
    }

    .hero-panel {
      border: 1px solid color-mix(in oklch, var(--fg) 18%, transparent);
      background: color-mix(in oklch, var(--bg) 55%, transparent);
      backdrop-filter: blur(18px);
      -webkit-backdrop-filter: blur(18px);
      padding: 22px;
      border-radius: 14px;
      display: grid;
      gap: 18px;
    }

    .manifest {
      width: min(100% - (var(--pad) * 2), 1380px);
      margin: clamp(24px, 5vw, 62px) auto 0;
      display: grid;
      grid-template-columns: minmax(0, 0.58fr) minmax(320px, 0.42fr);
      min-height: 220px;
      border: 1px solid color-mix(in oklch, var(--fg) 12%, transparent);
      background:
        linear-gradient(90deg, color-mix(in oklch, var(--surface) 72%, transparent), color-mix(in oklch, var(--bg) 86%, transparent)),
        repeating-linear-gradient(0deg, transparent 0, transparent 38px, color-mix(in oklch, var(--fg) 6%, transparent) 39px);
    }

    .manifest > * {
      padding: clamp(18px, 3vw, 34px);
      border-right: 1px solid color-mix(in oklch, var(--fg) 12%, transparent);
    }
    .manifest > *:last-child { border-right: 0; }
    .manifest-title {
      font-family: var(--font-display);
      font-size: clamp(34px, 5vw, 72px);
      line-height: 0.96;
      text-wrap: balance;
    }
    .manifest-copy {
      align-self: end;
      color: var(--muted);
      font-size: clamp(17px, 1.35vw, 22px);
      line-height: 1.55;
      text-wrap: pretty;
    }
    .manifest-mark {
      display: flex;
      flex-direction: column;
      justify-content: space-between;
      font-family: var(--font-mono);
      color: var(--subtle);
      font-size: 11px;
      letter-spacing: 0.16em;
      text-transform: uppercase;
    }
    .manifest-mark b {
      color: var(--fg);
      font-family: var(--font-display);
      font-size: clamp(54px, 7vw, 96px);
      font-weight: 500;
      letter-spacing: 0;
      line-height: 0.85;
      text-transform: none;
    }

    .panel-row {
      display: grid;
      grid-template-columns: 68px 1fr;
      gap: 16px;
      align-items: start;
      padding-bottom: 16px;
      border-bottom: 1px solid color-mix(in oklch, var(--fg) 14%, transparent);
    }
    .panel-row:last-child { padding-bottom: 0; border-bottom: 0; }
    .panel-code {
      font-family: var(--font-mono);
      color: var(--accent);
      font-size: 12px;
      letter-spacing: 0.18em;
    }
    .panel-row strong { display: block; font-size: 16px; margin-bottom: 4px; }
    .panel-row span { color: var(--muted); font-size: 14px; }

    main { position: relative; }
    .section {
      width: min(100% - (var(--pad) * 2), var(--max));
      margin: 0 auto;
      padding: clamp(74px, 10vw, 142px) 0;
      border-top: 1px solid color-mix(in oklch, var(--fg) 10%, transparent);
    }

    .section-head {
      display: grid;
      grid-template-columns: 0.36fr 0.64fr;
      gap: clamp(24px, 5vw, 72px);
      align-items: start;
      margin-bottom: clamp(30px, 5vw, 56px);
    }

    .section-label {
      font-family: var(--font-mono);
      color: var(--muted);
      font-size: 12px;
      letter-spacing: 0.2em;
      text-transform: uppercase;
    }

    .fit-illustration {
      width: min(100%, 360px);
      margin-top: clamp(22px, 4vw, 38px);
      opacity: 0.9;
    }
    .section-illustration {
      width: min(100%, 360px);
      margin-top: clamp(22px, 4vw, 38px);
      opacity: 0.9;
    }
    .section-illustration.teacher-illustration {
      width: min(100%, 414px);
    }
    .fit-illustration img,
    .section-illustration img {
      width: 100%;
      height: auto;
      display: block;
      filter: drop-shadow(0 0 28px rgba(255, 255, 255, 0.08));
    }

    h2 {
      font-family: var(--font-display);
      font-weight: 500;
      font-size: clamp(38px, 5.8vw, 84px);
      line-height: 0.95;
      text-wrap: balance;
    }

    .lead {
      color: var(--muted);
      font-size: clamp(17px, 1.8vw, 22px);
      max-width: 760px;
      margin-top: 18px;
      text-wrap: pretty;
    }

    .fit-grid {
      display: grid;
      grid-template-columns: repeat(5, 1fr);
      border: 1px solid var(--border);
      background: linear-gradient(135deg, color-mix(in oklch, var(--surface) 92%, transparent), color-mix(in oklch, var(--surface-2) 86%, transparent));
    }

    .fit-item {
      min-height: 190px;
      padding: 20px;
      border-right: 1px solid var(--border);
      display: flex;
      flex-direction: column;
      justify-content: space-between;
      position: relative;
      overflow: hidden;
    }
    .fit-item:last-child { border-right: 0; }
    .fit-item::before {
      content: "";
      position: absolute;
      inset: 0;
      background-image: linear-gradient(color-mix(in oklch, var(--fg) 7%, transparent) 1px, transparent 1px), linear-gradient(90deg, color-mix(in oklch, var(--fg) 7%, transparent) 1px, transparent 1px);
      background-size: 34px 34px;
      opacity: 0;
      transition: opacity 180ms cubic-bezier(0.23, 1, 0.32, 1);
    }
    .fit-item:hover::before { opacity: 1; }
    .fit-item span { position: relative; font-family: var(--font-mono); color: var(--subtle); font-size: 12px; letter-spacing: 0.16em; }
    .fit-item strong { position: relative; font-size: 22px; line-height: 1.1; max-width: 14ch; }

    .format-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 14px;
    }

    .format-card {
      min-height: 440px;
      border: 1px solid var(--border);
      background:
        linear-gradient(180deg, color-mix(in oklch, var(--surface-2) 86%, transparent), color-mix(in oklch, var(--surface) 72%, transparent)),
        radial-gradient(circle at 80% 16%, color-mix(in oklch, var(--fg) 10%, transparent), transparent 16rem);
      border-radius: 14px;
      padding: 24px;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
      transition: transform 200ms cubic-bezier(0.23, 1, 0.32, 1), border-color 200ms cubic-bezier(0.23, 1, 0.32, 1);
    }
    .format-card:hover { transform: translateY(-4px); border-color: color-mix(in oklch, var(--fg) 34%, transparent); }
    .format-top { display: grid; gap: 18px; }
    .format-meta { font-family: var(--font-mono); color: var(--muted); font-size: 12px; letter-spacing: 0.15em; text-transform: uppercase; }
    .format-card h3 { font-family: var(--font-display); font-size: clamp(34px, 4vw, 52px); line-height: 0.95; font-weight: 500; }
    .format-card p { color: var(--muted); font-size: 16px; }
    .format-list { display: grid; gap: 12px; margin-top: 24px; color: color-mix(in oklch, var(--fg) 82%, transparent); }
    .format-list div { display: grid; grid-template-columns: 18px 1fr; gap: 12px; align-items: start; }
    .format-list div:last-child { margin-bottom: 18px; }
    .mark { width: 8px; height: 8px; border: 1px solid var(--fg); border-radius: 50%; margin-top: 8px; }

    .story {
      display: grid;
      grid-template-columns: minmax(280px, 0.46fr) minmax(0, 0.54fr);
      gap: clamp(22px, 4vw, 52px);
      align-items: stretch;
    }

    .portrait-card {
      min-height: 680px;
      border: 1px solid var(--border);
      border-radius: 16px;
      background: url("/resources/math-tutor/images/portrait-card.jpg") center / cover no-repeat;
      position: relative;
      overflow: hidden;
    }
    .portrait-card::after {
      content: "";
      position: absolute;
      inset: 0;
      background: linear-gradient(180deg, transparent 35%, rgba(0, 0, 0, 0.76));
    }
    .portrait-caption {
      position: absolute;
      left: 22px;
      right: 22px;
      bottom: 22px;
      z-index: 1;
      display: flex;
      justify-content: space-between;
      gap: 18px;
      color: var(--fg);
      font-family: var(--font-mono);
      font-size: 11px;
      letter-spacing: 0.14em;
      text-transform: uppercase;
    }

    .proof-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 12px;
    }
    .proof {
      min-height: 190px;
      border: 1px solid var(--border);
      border-radius: 14px;
      padding: 22px;
      background: color-mix(in oklch, var(--surface) 82%, transparent);
      display: grid;
      align-content: space-between;
    }
    .proof b { font-size: 20px; line-height: 1.18; }
    .proof span { color: var(--muted); font-size: 14px; margin-top: 10px; }

    .method-band {
      border: 1px solid var(--border);
      border-radius: 16px;
      background:
        linear-gradient(90deg, color-mix(in oklch, var(--surface) 78%, transparent), color-mix(in oklch, var(--bg) 70%, transparent)),
        repeating-linear-gradient(90deg, transparent 0, transparent 94px, color-mix(in oklch, var(--fg) 7%, transparent) 95px);
      overflow: hidden;
    }

    .method-row {
      display: grid;
      grid-template-columns: 80px 0.38fr 1fr;
      gap: 24px;
      padding: 24px;
      border-bottom: 1px solid var(--border);
      align-items: center;
    }
    .method-row:last-child { border-bottom: 0; }
    .method-row .num { font-family: var(--font-mono); color: var(--muted); letter-spacing: 0.18em; }
    .method-row h3 { font-family: var(--font-display); font-size: clamp(28px, 3vw, 42px); line-height: 1; font-weight: 500; }
    .method-row p { color: var(--muted); max-width: 62ch; }

    .quote-section {
      width: min(100% - (var(--pad) * 2), 1380px);
      margin: 0 auto;
      padding: clamp(84px, 12vw, 168px) 0;
    }
    .quote-card {
      position: relative;
      min-height: 520px;
      display: grid;
      align-items: end;
      border-radius: 18px;
      overflow: hidden;
      padding: clamp(28px, 6vw, 76px);
      border: 1px solid color-mix(in oklch, var(--fg) 14%, transparent);
      background:
        linear-gradient(90deg, rgba(0, 0, 0, 0.78), rgba(0, 0, 0, 0.28)),
        url("/resources/math-tutor/images/quote-background.jpg") center 42% / cover no-repeat;
    }
    .quote-card blockquote {
      margin: 0;
      max-width: 980px;
      font-family: var(--font-display);
      font-size: clamp(38px, 5.4vw, 88px);
      line-height: 0.98;
      text-wrap: balance;
    }
    .quote-card cite {
      display: block;
      margin-top: 24px;
      color: var(--muted);
      font-style: normal;
      font-family: var(--font-mono);
      letter-spacing: 0.14em;
      text-transform: uppercase;
      font-size: 12px;
    }

    .apply {
      width: min(100% - (var(--pad) * 2), var(--max));
      margin: 0 auto clamp(42px, 7vw, 90px);
      border: 1px solid color-mix(in oklch, var(--fg) 16%, transparent);
      border-radius: 18px;
      background:
        radial-gradient(circle at 18% 20%, color-mix(in oklch, var(--fg) 10%, transparent), transparent 18rem),
        linear-gradient(135deg, color-mix(in oklch, var(--surface-2) 86%, transparent), color-mix(in oklch, var(--surface) 72%, transparent));
      padding: clamp(24px, 5vw, 58px);
      display: grid;
      grid-template-columns: 0.45fr 0.55fr;
      gap: clamp(24px, 5vw, 62px);
      align-items: start;
    }

    .apply h2 { font-size: clamp(44px, 6vw, 90px); }
    .apply-note {
      margin-top: 22px;
      color: var(--muted);
      font-size: 18px;
      max-width: 36ch;
    }

    .form {
      display: grid;
      gap: 14px;
    }
    .field { display: grid; gap: 7px; }
    .field label { color: var(--muted); font-size: 13px; }
    .field input,
    .field select,
    .field textarea {
      width: 100%;
      border: 1px solid color-mix(in oklch, var(--fg) 16%, transparent);
      background: color-mix(in oklch, var(--bg) 58%, transparent);
      color: var(--fg);
      border-radius: 12px;
      min-height: 52px;
      padding: 13px 14px;
      outline: 0;
      transition: border-color 160ms cubic-bezier(0.23, 1, 0.32, 1), background 160ms cubic-bezier(0.23, 1, 0.32, 1);
    }
    .field textarea { min-height: 118px; resize: vertical; }
    .field input:focus,
    .field select:focus,
    .field textarea:focus { border-color: var(--fg); background: color-mix(in oklch, var(--bg) 72%, transparent); }
    .field select.prefilled { border-color: color-mix(in oklch, var(--success) 72%, transparent); }
    .field.error input,
    .field.error select,
    .field.error textarea { border-color: var(--danger); }
    .error-text { min-height: 16px; color: var(--danger); font-size: 12px; }
    .form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
    .submit-row { display: flex; flex-wrap: wrap; gap: 14px; align-items: center; margin-top: 4px; }
    .status { color: var(--muted); font-size: 14px; min-height: 20px; }
    .status.ok { color: var(--success); }
    .status.warn { color: var(--danger); }
    .btn:disabled {
      cursor: progress;
      opacity: 0.7;
      transform: none;
    }

    footer {
      width: min(100% - (var(--pad) * 2), var(--max));
      margin: 0 auto;
      padding: 28px 0 44px;
      border-top: 1px solid var(--border);
      color: var(--subtle);
      display: flex;
      justify-content: space-between;
      gap: 20px;
      font-family: var(--font-mono);
      font-size: 11px;
      letter-spacing: 0.14em;
      text-transform: uppercase;
    }
    footer a {
      color: color-mix(in oklch, var(--fg) 48%, transparent);
      text-decoration: none;
      transition: color 160ms cubic-bezier(0.23, 1, 0.32, 1);
    }
    footer a:hover { color: var(--fg); }

    @media (max-width: 980px) {
      .nav { grid-template-columns: 1fr auto; }
      .nav-links { display: none; }
      .hero { min-height: 92svh; }
      .hero-inner,
      .manifest,
      .section-head,
      .story,
      .apply { grid-template-columns: 1fr; }
      .manifest > * { border-right: 0; border-bottom: 1px solid color-mix(in oklch, var(--fg) 12%, transparent); }
      .manifest > *:last-child { border-bottom: 0; }
      .hero-panel { max-width: 520px; }
      .fit-illustration,
      .section-illustration { max-width: 240px; margin-top: 18px; }
      .fit-grid { grid-template-columns: 1fr 1fr; }
      .fit-item { border-bottom: 1px solid var(--border); }
      .fit-item:nth-child(2n) { border-right: 0; }
      .fit-item:last-child { grid-column: 1 / -1; }
      .format-grid { grid-template-columns: 1fr; }
      .format-card { min-height: 330px; }
      .portrait-card { min-height: 520px; }
    }

    @media (min-width: 641px) and (max-width: 980px) {
      .hero {
        min-height: auto;
        align-items: start;
        padding-top: 132px;
        padding-bottom: 74px;
      }
    }

    @media (max-width: 640px) {
      .nav { top: 10px; width: calc(100% - 18px); padding: 8px 8px 8px 13px; gap: 10px; }
      .brand { font-size: 10px; letter-spacing: 0.1em; }
      .nav-cta { min-height: 38px; padding: 0 12px; font-size: 13px; }
      #apply { scroll-margin-top: 96px; }
      .hero {
        min-height: auto;
        height: auto !important;
        align-items: start;
        padding-top: clamp(290px, calc(48svh + 20px), 410px) !important;
        padding-bottom: 34px;
      }
      .hero::before {
        background-position: center, center, 54% -195px;
        background-size: auto, auto, auto 780px;
        background-repeat: no-repeat, no-repeat, no-repeat;
        background-image:
          linear-gradient(180deg, transparent 0%, transparent 12%, rgba(0, 0, 0, 0.76) 30%, rgba(0, 0, 0, 0.98) 50%, var(--bg) 100%),
          linear-gradient(90deg, rgba(0, 0, 0, 0.2) 0%, rgba(0, 0, 0, 0.1) 100%),
          url("/resources/math-tutor/images/hero-portrait.jpg");
      }
      .hero::after { display: none; }
      h1 { font-size: clamp(48px, 16vw, 76px); }
      .hero-copy { font-size: 17px; }
      .hero-actions { flex-direction: column; align-items: stretch; }
      .btn { width: 100%; }
      .section { padding: 70px 0; }
      .fit-grid, .proof-grid, .form-grid { grid-template-columns: 1fr; }
      .fit-item, .fit-item:nth-child(2n) { border-right: 0; }
      .fit-item { min-height: 146px; }
      .method-row { grid-template-columns: 1fr; gap: 10px; }
      .quote-card { min-height: 440px; background-position: 52% center; }
      footer { flex-direction: column; }
    }