:root {
      --bg: #05070a;
      --bg-elevated: #0b0f16;
      --bg-card: #0d1219;
      --border: #1f2937;
      --border-light: #2d3748;
      --primary: #3b82f6;
      --primary-light: #60a5fa;
      --primary-lighter: #93c5fd;
      --accent: #818cf8;
      --accent-purple: #c084fc;
      --text: #f5f5f5;
      --text-body: #d1d5db;
      --text-muted: #9ca3af;
      --text-dim: #6b7280;
    }

    * { box-sizing: border-box; }
    html { scroll-behavior: smooth; }

    body {
      font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
      margin: 0;
      background: var(--bg);
      color: var(--text);
      overflow-x: hidden;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }

    h1, h2, h3, h4 {
      font-family: 'Space Grotesk', 'Inter', sans-serif;
      letter-spacing: -0.025em;
      color: var(--text);
    }

    /* ===== HERO ===== */
    header {
      position: relative;
      padding: 90px 20px 110px;
      overflow: hidden;
      background:
        radial-gradient(ellipse 80% 60% at 50% 0%, rgba(59, 130, 246, 0.18), transparent 70%),
        radial-gradient(ellipse 50% 40% at 85% 60%, rgba(129, 140, 248, 0.10), transparent 70%),
        radial-gradient(ellipse 40% 30% at 15% 80%, rgba(192, 132, 252, 0.06), transparent 70%),
        var(--bg);
      border-bottom: 1px solid var(--border);
    }

    .hero-bg {
      position: absolute; inset: 0; pointer-events: none; overflow: hidden;
    }
    .hero-grid {
      position: absolute; inset: 0;
      background-image:
        linear-gradient(rgba(59, 130, 246, 0.06) 1px, transparent 1px),
        linear-gradient(90deg, rgba(59, 130, 246, 0.06) 1px, transparent 1px);
      background-size: 60px 60px;
      mask-image: radial-gradient(ellipse 70% 60% at 50% 40%, black 30%, transparent 80%);
      -webkit-mask-image: radial-gradient(ellipse 70% 60% at 50% 40%, black 30%, transparent 80%);
    }

    .hero-content {
      position: relative;
      max-width: 1200px;
      margin: 0 auto;
      display: grid;
      grid-template-columns: 1.15fr 1fr;
      gap: 60px;
      align-items: center;
      text-align: left;
    }

    .hero-badge {
      display: inline-flex; align-items: center; gap: 10px;
      padding: 7px 14px 7px 12px;
      border-radius: 999px;
      border: 1px solid rgba(96, 165, 250, 0.25);
      background: rgba(59, 130, 246, 0.08);
      font-size: 0.78rem; font-weight: 500;
      color: var(--primary-light);
      margin-bottom: 24px;
      letter-spacing: 0.02em;
    }
    .hero-badge::before {
      content: ''; width: 7px; height: 7px; border-radius: 50%;
      background: var(--primary-light);
      box-shadow: 0 0 12px var(--primary-light);
      animation: pulse 2.2s ease-in-out infinite;
    }
    @keyframes pulse {
      0%, 100% { opacity: 1; transform: scale(1); }
      50% { opacity: 0.4; transform: scale(0.85); }
    }

    h1 {
      margin: 0 0 22px;
      font-size: clamp(2.2rem, 4.8vw, 3.9rem);
      font-weight: 700;
      line-height: 1.05;
    }
    .gradient {
      background: linear-gradient(135deg, #60a5fa 0%, #818cf8 50%, #c084fc 100%);
      -webkit-background-clip: text;
      background-clip: text;
      -webkit-text-fill-color: transparent;
    }
    .tagline {
      font-size: 1.15rem; line-height: 1.65;
      color: var(--text-body);
      max-width: 560px; margin: 0 0 32px;
    }

    .pills { display: flex; flex-wrap: wrap; gap: 10px; }
    .pill {
      display: inline-flex; align-items: center; gap: 8px;
      padding: 9px 16px;
      border-radius: 999px;
      border: 1px solid var(--border-light);
      background: rgba(255, 255, 255, 0.02);
      font-size: 0.85rem; font-weight: 500;
      color: var(--text-body);
      transition: all 0.25s ease;
    }
    .pill:hover {
      border-color: var(--primary);
      background: rgba(59, 130, 246, 0.1);
      transform: translateY(-1px);
    }
    .pill .dot { width: 6px; height: 6px; border-radius: 50%; background: var(--primary-light); }

    .hero-visual {
      position: relative;
      aspect-ratio: 1;
      max-width: 460px;
      justify-self: end;
      width: 100%;
    }
    .car-svg {
      width: 100%; height: auto;
      animation: float 7s ease-in-out infinite;
      filter: drop-shadow(0 30px 50px rgba(59, 130, 246, 0.25));
    }
    @keyframes float {
      0%, 100% { transform: translateY(0); }
      50% { transform: translateY(-12px); }
    }
    .visual-orbit { position: absolute; inset: 0; pointer-events: none; }
    .visual-orbit .ring {
      position: absolute; inset: 0; border-radius: 50%;
      border: 1px dashed rgba(96, 165, 250, 0.2);
      animation: spin 60s linear infinite;
    }
    .visual-orbit .ring.r2 {
      inset: 12%; border-color: rgba(129, 140, 248, 0.15);
      animation-direction: reverse; animation-duration: 45s;
    }
    @keyframes spin { to { transform: rotate(360deg); } }

    /* ===== MAIN ===== */
    main {
      max-width: 1200px;
      margin: 0 auto;
      padding: 80px 20px 100px;
    }
    section { margin-bottom: 110px; }
    section:last-child { margin-bottom: 0; }

    .section-header {
      display: flex; align-items: center; gap: 14px;
      margin-bottom: 28px;
    }
    .section-number {
      font-family: 'Space Grotesk', sans-serif;
      font-size: 0.85rem; font-weight: 700;
      color: var(--primary-light);
      background: rgba(59, 130, 246, 0.10);
      padding: 7px 12px;
      border-radius: 8px;
      border: 1px solid rgba(59, 130, 246, 0.22);
      letter-spacing: 0.05em;
    }
    h2 {
      margin: 0;
      font-size: clamp(1.6rem, 3vw, 2.3rem);
      font-weight: 700;
    }
    p {
      line-height: 1.7;
      max-width: 820px;
      margin: 12px 0;
      color: var(--text-body);
    }
    .highlight {
      color: var(--primary-light); font-weight: 600;
    }
    strong { color: #fff; font-weight: 600; }

    /* ===== CARDS ===== */
    .grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
      gap: 20px;
      margin-top: 36px;
    }
    .card {
      background: linear-gradient(180deg, rgba(13, 18, 25, 0.6), rgba(11, 15, 22, 0.8));
      border-radius: 16px;
      padding: 26px;
      border: 1px solid var(--border);
      position: relative; overflow: hidden;
      transition: all 0.3s ease;
    }
    .card::before {
      content: ''; position: absolute;
      top: 0; left: 0; right: 0; height: 1px;
      background: linear-gradient(90deg, transparent, var(--primary), transparent);
      opacity: 0; transition: opacity 0.3s ease;
    }
    .card:hover {
      border-color: var(--border-light);
      transform: translateY(-4px);
      background: linear-gradient(180deg, rgba(13, 18, 25, 0.9), rgba(11, 15, 22, 1));
    }
    .card:hover::before { opacity: 1; }

    .card-icon {
      width: 46px; height: 46px;
      border-radius: 12px;
      background: rgba(59, 130, 246, 0.12);
      border: 1px solid rgba(59, 130, 246, 0.22);
      display: flex; align-items: center; justify-content: center;
      margin-bottom: 18px;
    }
    .card-icon svg {
      width: 22px; height: 22px;
      stroke: var(--primary-light);
      fill: none; stroke-width: 1.8;
      stroke-linecap: round; stroke-linejoin: round;
    }
    .badge {
      font-size: 0.72rem;
      text-transform: uppercase;
      letter-spacing: 0.14em;
      color: var(--text-muted);
      font-weight: 600;
    }
    .card h3 { margin: 10px 0 12px; font-size: 1.15rem; font-weight: 600; }
    .card p { font-size: 0.95rem; margin: 0; }

    /* ===== MODES ===== */
    .modes-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
      gap: 22px;
      margin-top: 36px;
    }
    .mode-card {
      background: var(--bg-card);
      border-radius: 18px;
      padding: 26px;
      border: 1px solid var(--border);
      position: relative; overflow: hidden;
      transition: all 0.3s ease;
    }
    .mode-card::after {
      content: ''; position: absolute;
      top: 0; right: 0;
      width: 120px; height: 120px;
      border-radius: 50%;
      filter: blur(60px);
      opacity: 0.15;
      pointer-events: none;
    }
    .mode-card.route::after { background: #3b82f6; }
    .mode-card.sport::after { background: #ef4444; }
    .mode-card.offroad::after { background: #f59e0b; }
    .mode-card.charge::after { background: #a855f7; }

    .mode-card:hover { transform: translateY(-3px); }
    .mode-card.route:hover { border-color: rgba(59, 130, 246, 0.5); }
    .mode-card.sport:hover { border-color: rgba(239, 68, 68, 0.5); }
    .mode-card.offroad:hover { border-color: rgba(245, 158, 11, 0.5); }
    .mode-card.charge:hover { border-color: rgba(168, 85, 247, 0.5); }

    .mode-head {
      display: flex; align-items: center; gap: 16px;
      margin-bottom: 22px; position: relative;
    }
    .mode-icon {
      width: 54px; height: 54px;
      border-radius: 14px;
      display: flex; align-items: center; justify-content: center;
      flex-shrink: 0;
    }
    .mode-icon svg { width: 28px; height: 28px; fill: none; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
    .mode-card.route .mode-icon { background: rgba(59, 130, 246, 0.15); border: 1px solid rgba(59, 130, 246, 0.3); }
    .mode-card.route .mode-icon svg { stroke: #60a5fa; }
    .mode-card.sport .mode-icon { background: rgba(239, 68, 68, 0.15); border: 1px solid rgba(239, 68, 68, 0.3); }
    .mode-card.sport .mode-icon svg { stroke: #f87171; }
    .mode-card.offroad .mode-icon { background: rgba(245, 158, 11, 0.15); border: 1px solid rgba(245, 158, 11, 0.3); }
    .mode-card.offroad .mode-icon svg { stroke: #fbbf24; }
    .mode-card.charge .mode-icon { background: rgba(168, 85, 247, 0.15); border: 1px solid rgba(168, 85, 247, 0.3); }
    .mode-card.charge .mode-icon svg { stroke: #c084fc; }

    .mode-name { font-family: 'Space Grotesk', sans-serif; font-size: 1.2rem; font-weight: 600; margin: 0; }
    .mode-sub { font-size: 0.85rem; color: var(--text-muted); margin: 2px 0 0; }

    .mode-specs { display: flex; flex-direction: column; gap: 2px; }
    .spec-row {
      display: flex; justify-content: space-between; align-items: center;
      padding: 11px 0;
      border-bottom: 1px dashed rgba(31, 41, 55, 0.7);
      font-size: 0.92rem;
      gap: 12px;
    }
    .spec-row:last-child { border-bottom: none; }
    .spec-label { color: var(--text-muted); font-weight: 500; flex-shrink: 0; }
    .spec-value { color: var(--text); font-weight: 500; text-align: right; }

    /* ===== BENEFITS ===== */
    .benefits-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
      gap: 16px;
      margin-top: 36px;
    }
    .benefit {
      display: flex; align-items: flex-start; gap: 16px;
      padding: 22px;
      background: var(--bg-card);
      border: 1px solid var(--border);
      border-radius: 14px;
      transition: all 0.3s ease;
    }
    .benefit:hover {
      border-color: var(--border-light);
      background: linear-gradient(135deg, rgba(59, 130, 246, 0.04), rgba(129, 140, 248, 0.02));
      transform: translateX(2px);
    }
    .benefit-num {
      font-family: 'Space Grotesk', sans-serif;
      font-size: 0.95rem; font-weight: 700;
      color: var(--primary-light);
      background: rgba(59, 130, 246, 0.10);
      width: 36px; height: 36px;
      border-radius: 10px;
      display: flex; align-items: center; justify-content: center;
      flex-shrink: 0;
      border: 1px solid rgba(59, 130, 246, 0.2);
    }
    .benefit h4 { margin: 2px 0 6px; font-size: 1rem; font-weight: 600; }
    .benefit p { font-size: 0.88rem; margin: 0; color: var(--text-muted); line-height: 1.55; }

    /* ===== STEPS ===== */
    .steps {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
      gap: 16px;
      margin-top: 36px;
    }
    .step {
      background: var(--bg-card);
      border: 1px solid var(--border);
      border-radius: 14px;
      padding: 22px;
      position: relative;
      transition: all 0.3s ease;
    }
    .step:hover { border-color: var(--border-light); transform: translateY(-2px); }
    .step-num {
      font-family: 'Space Grotesk', sans-serif;
      font-size: 0.72rem; font-weight: 700;
      color: var(--primary-light);
      letter-spacing: 0.14em;
      display: inline-block;
      margin-bottom: 10px;
      padding: 4px 9px;
      border-radius: 6px;
      background: rgba(59, 130, 246, 0.08);
      border: 1px solid rgba(59, 130, 246, 0.18);
    }
    .step h4 { margin: 0 0 8px; font-size: 1rem; font-weight: 600; }
    .step p { font-size: 0.88rem; margin: 0; color: var(--text-muted); }

    /* ===== LISTS ===== */
    ul {
      max-width: 820px;
      margin: 16px 0;
      padding-left: 0;
      list-style: none;
    }
    ul li {
      position: relative;
      padding-left: 28px;
      margin-bottom: 10px;
      line-height: 1.65;
      color: var(--text-body);
    }
    ul li::before {
      content: ''; position: absolute;
      left: 0; top: 13px;
      width: 16px; height: 2px;
      background: linear-gradient(90deg, var(--primary), var(--accent));
      border-radius: 1px;
    }
    ul li::after {
      content: ''; position: absolute;
      left: 14px; top: 11px;
      width: 6px; height: 6px;
      border-radius: 50%;
      background: var(--primary-light);
      box-shadow: 0 0 8px var(--primary-light);
    }

    /* ===== FINAL CALLOUT ===== */
    .callout {
      margin-top: 50px;
      padding: 36px;
      border-radius: 20px;
      background:
        radial-gradient(ellipse at top left, rgba(59, 130, 246, 0.15), transparent 60%),
        radial-gradient(ellipse at bottom right, rgba(192, 132, 252, 0.12), transparent 60%),
        var(--bg-card);
      border: 1px solid var(--border-light);
      text-align: center;
      position: relative; overflow: hidden;
    }
    .callout::before {
      content: ''; position: absolute;
      top: 0; left: 0; right: 0; height: 1px;
      background: linear-gradient(90deg, transparent, var(--primary-light), var(--accent-purple), transparent);
    }
    .callout h3 { font-size: clamp(1.3rem, 2.5vw, 1.7rem); font-weight: 700; margin: 0 0 12px; }
    .callout p { margin: 0 auto; max-width: 700px; color: var(--text-body); }

    /* ===== FOOTER ===== */
    footer {
      padding: 50px 20px 40px;
      border-top: 1px solid var(--border);
      background: rgba(0, 0, 0, 0.3);
      text-align: center;
    }
    .footer-inner { max-width: 1200px; margin: 0 auto; }
    .footer-brand {
      font-family: 'Space Grotesk', sans-serif;
      font-weight: 600;
      color: var(--text);
      margin-bottom: 8px;
      font-size: 0.95rem;
    }
    .footer-brand .gradient {
      background: linear-gradient(135deg, #60a5fa, #c084fc);
      -webkit-background-clip: text;
      background-clip: text;
      -webkit-text-fill-color: transparent;
    }
    .footer-meta { font-size: 0.82rem; color: var(--text-muted); }
    .footer-dots { display: flex; justify-content: center; gap: 6px; margin-top: 18px; }
    .footer-dots span {
      width: 5px; height: 5px;
      border-radius: 50%;
      background: var(--primary-light);
      opacity: 0.4;
    }
    .footer-dots span:nth-child(2) { opacity: 0.7; }
    .footer-dots span:nth-child(3) { opacity: 1; }

    /* =============================================== */
    /* ========== SCIENTIFIC & MATH SECTION ========== */
    /* =============================================== */

    .math-intro {
      font-size: 1.05rem;
      color: var(--text-body);
      max-width: 820px;
      margin-bottom: 36px;
    }

    .math-block {
      background: linear-gradient(180deg, rgba(13, 18, 25, 0.7), rgba(11, 15, 22, 0.9));
      border: 1px solid var(--border);
      border-radius: 18px;
      padding: 32px;
      margin-top: 24px;
      position: relative;
      overflow: hidden;
    }

    .math-block::before {
      content: '';
      position: absolute;
      top: 0; left: 24px;
      width: 80px; height: 2px;
      background: linear-gradient(90deg, var(--primary), var(--accent-purple));
      border-radius: 1px;
    }

    .math-block h3 {
      margin: 0 0 8px;
      font-size: 1.3rem;
      font-weight: 600;
    }

    .math-block h3 .num {
      font-family: 'JetBrains Mono', monospace;
      color: var(--primary-light);
      font-size: 0.95rem;
      margin-right: 10px;
      font-weight: 500;
    }

    .math-block > p {
      font-size: 0.95rem;
      color: var(--text-muted);
      margin: 0 0 20px;
      max-width: 100%;
    }

    .formula {
      background: rgba(5, 7, 10, 0.6);
      border: 1px solid var(--border);
      border-radius: 12px;
      padding: 20px 24px;
      margin: 14px 0;
      position: relative;
    }

    .formula-label {
      font-family: 'Space Grotesk', sans-serif;
      font-size: 0.8rem;
      font-weight: 600;
      color: var(--primary-light);
      text-transform: uppercase;
      letter-spacing: 0.1em;
      margin-bottom: 12px;
      display: flex;
      align-items: center;
      gap: 8px;
    }

    .formula-label::before {
      content: 'Æ'';
      font-family: 'JetBrains Mono', monospace;
      font-size: 1rem;
      color: var(--primary);
      background: rgba(59, 130, 246, 0.12);
      width: 22px; height: 22px;
      border-radius: 6px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
    }

    .formula-body {
      overflow-x: auto;
      padding: 8px 0;
      text-align: center;
    }

    .katex-display {
      margin: 8px 0 !important;
      color: var(--text) !important;
    }

    .katex {
      color: var(--text) !important;
      font-size: 1.05em;
    }

    .formula-vars {
      margin-top: 12px;
      padding-top: 12px;
      border-top: 1px dashed var(--border);
      font-size: 0.85rem;
      color: var(--text-muted);
      font-family: 'JetBrains Mono', monospace;
      line-height: 1.6;
    }

    .formula-vars code {
      background: rgba(59, 130, 246, 0.1);
      color: var(--primary-light);
      padding: 2px 6px;
      border-radius: 4px;
      font-size: 0.82rem;
      margin: 0 2px;
    }

    /* Geometry diagram */
    .geometry-diagram {
      margin: 28px auto 0;
      max-width: 600px;
      background: rgba(5, 7, 10, 0.4);
      border: 1px solid var(--border);
      border-radius: 14px;
      padding: 20px;
    }

    .geometry-diagram svg { width: 100%; height: auto; }

    .legend {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
      gap: 10px;
      margin-top: 16px;
      font-size: 0.85rem;
    }

    .legend-item {
      display: flex; align-items: center; gap: 8px;
      color: var(--text-muted);
    }

    .legend-item .swatch {
      width: 14px; height: 14px;
      border-radius: 4px;
      flex-shrink: 0;
    }

    /* Spec table (typical values) */
    .specs-table {
      width: 100%;
      border-collapse: collapse;
      margin: 20px 0 4px;
      font-size: 0.92rem;
    }

    .specs-table th {
      text-align: left;
      padding: 12px 14px;
      background: rgba(59, 130, 246, 0.08);
      color: var(--primary-light);
      font-weight: 600;
      font-size: 0.78rem;
      text-transform: uppercase;
      letter-spacing: 0.1em;
      border-bottom: 1px solid var(--border-light);
    }

    .specs-table th:first-child { border-top-left-radius: 8px; }
    .specs-table th:last-child { border-top-right-radius: 8px; }

    .specs-table td {
      padding: 11px 14px;
      border-bottom: 1px solid var(--border);
      color: var(--text-body);
      font-family: 'JetBrains Mono', monospace;
      font-size: 0.88rem;
    }

    .specs-table tr:last-child td { border-bottom: none; }
    .specs-table tr:hover td { background: rgba(59, 130, 246, 0.04); }
    .specs-table td:first-child { color: var(--text); font-family: 'Inter', sans-serif; font-weight: 500; }

    /* Performance metrics callout */
    .perf-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
      gap: 16px;
      margin-top: 32px;
    }

    .perf-card {
      background: var(--bg-card);
      border: 1px solid var(--border);
      border-radius: 14px;
      padding: 20px;
      text-align: center;
      transition: all 0.3s ease;
    }

    .perf-card:hover {
      border-color: var(--primary);
      transform: translateY(-3px);
      background: linear-gradient(180deg, rgba(59, 130, 246, 0.06), var(--bg-card));
    }

    .perf-value {
      font-family: 'Space Grotesk', sans-serif;
      font-size: 2rem;
      font-weight: 700;
      background: linear-gradient(135deg, #60a5fa, #c084fc);
      -webkit-background-clip: text;
      background-clip: text;
      -webkit-text-fill-color: transparent;
      line-height: 1;
      margin-bottom: 6px;
    }

    .perf-unit {
      font-size: 0.9rem;
      color: var(--text-body);
      font-weight: 500;
      margin-bottom: 6px;
    }

    .perf-label {
      font-size: 0.78rem;
      color: var(--text-muted);
      line-height: 1.4;
    }

    /* Algorithm pipeline */
    .pipeline {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
      gap: 12px;
      margin: 24px 0 4px;
    }

    .pipe-step {
      background: rgba(5, 7, 10, 0.5);
      border: 1px solid var(--border);
      border-left: 3px solid var(--primary);
      border-radius: 10px;
      padding: 16px;
      position: relative;
    }

    .pipe-step .pipe-num {
      font-family: 'JetBrains Mono', monospace;
      font-size: 0.75rem;
      color: var(--primary-light);
      margin-bottom: 6px;
      font-weight: 600;
    }

    .pipe-step h5 {
      margin: 0 0 6px;
      font-size: 0.92rem;
      font-weight: 600;
      color: var(--text);
    }

    .pipe-step p {
      font-size: 0.8rem;
      color: var(--text-muted);
      margin: 0;
      line-height: 1.5;
    }

    /* ===== RESPONSIVE ===== */
    @media (max-width: 900px) {
      .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 30px;
      }
      .hero-visual {
        max-width: 320px;
        margin: 30px auto 0;
        justify-self: center;
      }
      .pills { justify-content: center; }
      .tagline { margin-left: auto; margin-right: auto; }
      .hero-badge { margin-left: auto; margin-right: auto; }
    }

    @media (max-width: 600px) {
      header { padding: 60px 16px 80px; }
      main { padding: 50px 16px 70px; }
      section { margin-bottom: 80px; }
      .card, .mode-card, .benefit, .step, .math-block { padding: 20px; }
      .formula { padding: 16px; }
      .callout { padding: 26px 20px; }
    }