:root {
      --bg: #f3f5f8;
      --surface: #ffffff;
      --ink: #122033;
      --muted: #566276;
      --line: #d7dee8;
      --gold: #c9a84c;
      --navy: #0a1628;
      --blue: #2f68c8;
      --red: #c54747;
      --green: #2f8c62;
      --amber: #b5740f;
      --radius: 16px;
      --shadow: 0 10px 30px rgba(10, 22, 40, 0.08);
    }

    * { box-sizing: border-box; }

    html {
      scroll-behavior: smooth;
    }

    body {
      margin: 0;
      font-family: "Segoe UI", "Helvetica Neue", Arial, sans-serif;
      background: radial-gradient(1200px 500px at 50% -100px, rgba(201, 168, 76, 0.16), transparent), var(--bg);
      color: var(--ink);
      line-height: 1.5;
    }

    .topbar {
      display: flex;
      justify-content: space-between;
      align-items: center;
      gap: 10px;
      flex-wrap: wrap;
      padding: 9px 18px;
      background: #0b0b12;
      border-bottom: 2px solid var(--gold);
      position: relative;
      z-index: 100;
    }

    .topbar a {
      color: #f5f2e8;
      text-decoration: none;
      font-size: 12px;
      letter-spacing: 0.5px;
      font-weight: 700;
    }

    .main-nav {
      position: sticky;
      top: 0;
      z-index: 90;
      backdrop-filter: blur(8px);
      background: rgba(255, 255, 255, 0.85);
      border-bottom: 1px solid var(--line);
    }

    .nav-inner {
      max-width: 1180px;
      margin: 0 auto;
      padding: 10px 16px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 12px;
      flex-wrap: wrap;
    }

    .brand {
      font-weight: 800;
      color: var(--navy);
      text-decoration: none;
      font-size: 20px;
      letter-spacing: -0.4px;
    }

    .brand span { color: var(--gold); }

    .nav-links {
      display: flex;
      gap: 8px;
      flex-wrap: wrap;
    }

    .nav-links a {
      text-decoration: none;
      color: var(--ink);
      border: 1px solid var(--line);
      background: #fff;
      padding: 6px 12px;
      border-radius: 999px;
      font-size: 13px;
      font-weight: 600;
    }

    .container {
      max-width: 1180px;
      margin: 0 auto;
      padding: 0 16px;
    }

    .hero {
      padding: 42px 0 20px;
    }

    .hero-grid {
      display: grid;
      grid-template-columns: 1.2fr 0.8fr;
      gap: 22px;
      align-items: stretch;
    }

    .card {
      background: var(--surface);
      border: 1px solid var(--line);
      border-radius: var(--radius);
      box-shadow: var(--shadow);
      padding: 22px;
    }

    .badge {
      display: inline-block;
      padding: 6px 11px;
      border-radius: 999px;
      border: 1px solid rgba(201, 168, 76, 0.4);
      background: rgba(201, 168, 76, 0.12);
      color: #866819;
      font-size: 12px;
      font-weight: 700;
      margin-bottom: 10px;
    }

    h1, h2, h3 {
      margin: 0 0 10px;
      line-height: 1.2;
      letter-spacing: -0.4px;
    }

    h1 { font-size: clamp(30px, 4vw, 52px); }
    h2 { font-size: clamp(24px, 3vw, 36px); margin-bottom: 8px; }
    h3 { font-size: clamp(18px, 2.3vw, 26px); }

    .sub {
      color: var(--muted);
      margin: 0 0 18px;
      max-width: 75ch;
    }

    .hero-actions {
      display: flex;
      gap: 10px;
      flex-wrap: wrap;
      margin-top: 16px;
    }

    .btn {
      text-decoration: none;
      font-weight: 700;
      border-radius: 12px;
      padding: 10px 14px;
      border: 1px solid transparent;
      display: inline-block;
      font-size: 14px;
    }

    .btn-primary {
      background: var(--gold);
      color: var(--navy);
    }

    .btn-ghost {
      background: #fff;
      border-color: var(--line);
      color: var(--ink);
    }

    .stat-grid {
      display: grid;
      grid-template-columns: repeat(4, minmax(0, 1fr));
      gap: 12px;
      margin-top: 14px;
    }

    .stat {
      background: #fff;
      border: 1px solid var(--line);
      border-radius: 12px;
      padding: 12px;
      text-align: center;
    }

    .stat strong {
      display: block;
      font-size: 22px;
      color: var(--navy);
      line-height: 1.1;
    }

    .section {
      padding: 34px 0;
    }

    .grid-2 {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 16px;
    }

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

    .grid-4 {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 12px;
    }

    .chip {
      border: 1px solid var(--line);
      border-radius: 12px;
      background: #fff;
      padding: 12px;
    }

    .formula {
      font-family: Consolas, "Courier New", monospace;
      background: #f8fafc;
      border: 1px solid var(--line);
      border-radius: 10px;
      padding: 10px;
      margin-top: 8px;
      color: #1d324f;
      font-size: 14px;
      overflow: auto;
    }

    .tabs {
      display: flex;
      gap: 8px;
      margin-bottom: 12px;
      flex-wrap: wrap;
    }

    .tab-btn {
      border: 1px solid var(--line);
      background: #fff;
      color: var(--ink);
      border-radius: 999px;
      padding: 8px 14px;
      font-weight: 700;
      cursor: pointer;
    }

    .tab-btn.active {
      background: var(--navy);
      color: var(--gold);
      border-color: var(--navy);
    }

    .tab-panel { display: none; }
    .tab-panel.active { display: block; }

    .bar-list {
      display: grid;
      gap: 8px;
    }

    .bar-row {
      display: grid;
      grid-template-columns: 120px 1fr auto;
      gap: 8px;
      align-items: center;
      font-size: 13px;
    }

    .bar-track {
      background: #e9edf3;
      height: 10px;
      border-radius: 999px;
      overflow: hidden;
    }

    .bar-fill {
      height: 100%;
      background: linear-gradient(90deg, #e2c36b 0%, #b68922 100%);
      border-radius: inherit;
    }

    .kpi-strip {
      background: linear-gradient(145deg, #0a1628, #122946);
      border-radius: 16px;
      padding: 20px;
      color: #fff;
      display: grid;
      gap: 14px;
      grid-template-columns: repeat(4, 1fr);
    }

    .kpi-strip strong {
      display: block;
      font-size: 30px;
      color: var(--gold);
      line-height: 1;
    }

    .kpi-strip span {
      font-size: 12px;
      color: #bfccde;
    }

    .calc-wrap {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 16px;
    }

    .control {
      margin-bottom: 10px;
    }

    .control label {
      display: flex;
      justify-content: space-between;
      font-size: 13px;
      color: var(--muted);
      margin-bottom: 4px;
      gap: 10px;
    }

    .control input[type="range"] {
      width: 100%;
      accent-color: #b48a2a;
    }

    .result-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 10px;
    }

    .result {
      border: 1px solid var(--line);
      border-radius: 10px;
      background: #f8fafc;
      padding: 10px;
    }

    .result small { color: var(--muted); display: block; }

    .result strong {
      display: block;
      font-family: Consolas, "Courier New", monospace;
      font-size: 19px;
      color: var(--navy);
      margin-top: 2px;
    }

    footer {
      margin-top: 34px;
      border-top: 1px solid var(--line);
      background: #fff;
    }

    .footer-inner {
      max-width: 1180px;
      margin: 0 auto;
      padding: 18px 16px 24px;
      color: #5f6d82;
      font-size: 13px;
    }

    @media (max-width: 980px) {
      .hero-grid,
      .grid-2,
      .calc-wrap {
        grid-template-columns: 1fr;
      }

      .grid-4 { grid-template-columns: repeat(2, 1fr); }
      .grid-3 { grid-template-columns: 1fr; }
      .kpi-strip { grid-template-columns: repeat(2, 1fr); }
    }

    @media (max-width: 680px) {
      .nav-links a { font-size: 12px; padding: 5px 9px; }
      .stat-grid { grid-template-columns: repeat(2, 1fr); }
      .bar-row { grid-template-columns: 1fr; gap: 4px; }
      .kpi-strip { grid-template-columns: 1fr; }
      .result-grid { grid-template-columns: 1fr; }
    }