:root {
      --ink: #172033;
      --muted: #647089;
      --paper: #fffdf9;
      --panel: #ffffff;
      --line: #e8eaf0;
      --blue: #3155e7;
      --violet: #7448e8;
      --coral: #ff5c5c;
      --yellow: #ffd84d;
      --mint: #27c8a5;
      --navy: #101934;
      --shadow: 0 18px 50px rgba(34, 42, 75, .11);
      --radius: 14px;
    }

    * { box-sizing: border-box; }
    html { scroll-behavior: smooth; }
    body {
      margin: 0;
      color: var(--ink);
      background: var(--paper);
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
      line-height: 1.7;
    }
    a { color: inherit; text-decoration: none; }
    img { max-width: 100%; height: auto; display: block; }
    button, input, select, textarea { font: inherit; }
    .container { width: min(1180px, calc(100% - 40px)); margin: 0 auto; }
    .section { padding: 88px 0; position: relative; }
    .section-head { max-width: 720px; margin-bottom: 38px; }
    .eyebrow {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      color: var(--blue);
      font-size: 13px;
      font-weight: 800;
      letter-spacing: 1px;
      text-transform: uppercase;
    }
    .eyebrow::before {
      content: "";
      width: 24px;
      height: 4px;
      border-radius: 4px;
      background: var(--coral);
    }
    h1, h2, h3, p { margin-top: 0; }
    h1, h2, h3 { line-height: 1.2; letter-spacing: 0; }
    h1 { font-size: clamp(38px, 6vw, 72px); margin-bottom: 22px; }
    h2 { font-size: clamp(28px, 4vw, 46px); margin-bottom: 14px; }
    h3 { font-size: 20px; margin-bottom: 10px; }
    .lead { color: var(--muted); font-size: 18px; max-width: 670px; }
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      min-height: 48px;
      padding: 0 22px;
      border: 1px solid transparent;
      border-radius: 8px;
      font-weight: 800;
      cursor: pointer;
      transition: transform .25s ease, box-shadow .25s ease, background .25s ease;
    }
    .btn:hover { transform: translateY(-3px); box-shadow: 0 12px 24px rgba(49, 85, 231, .18); }
    .btn-primary { color: #fff; background: var(--blue); }
    .btn-light { color: var(--navy); background: #fff; }
    .btn-outline { color: var(--blue); background: #fff; border-color: #cdd5f7; }
    .site-header {
      position: sticky;
      top: 0;
      z-index: 20;
      background: rgba(255,253,249,.94);
      border-bottom: 1px solid rgba(232,234,240,.9);
      backdrop-filter: blur(14px);
    }
    .nav-wrap {
      min-height: 76px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 24px;
    }
    .brand { display: inline-flex; align-items: center; flex: 0 0 auto; }
    .ai-page-logo { width: 132px; }
    .nav-links {
      display: flex;
      align-items: center;
      justify-content: flex-end;
      gap: 0;
      flex-wrap: wrap;
    }
    .nav-links a {
      display: inline-flex;
      padding: 8px 9px;
      color: #39445d;
      font-size: 13px;
      font-weight: 700;
      white-space: nowrap;
      transition: color .2s ease;
    }
    .nav-links a:hover, .nav-links a.active { color: var(--blue); }
    .nav-cta { margin-left: 12px; }
    .menu-toggle {
      display: none;
      border: 0;
      background: transparent;
      color: var(--ink);
      font-size: 25px;
      cursor: pointer;
    }

    .hero {
      position: relative;
      overflow: hidden;
      color: #fff;
      background: var(--navy);
      padding: 100px 0 74px;
    }
    .hero::before, .hero::after {
      content: "";
      position: absolute;
      pointer-events: none;
      transform: rotate(14deg);
    }
    .hero::before {
      width: 280px;
      height: 520px;
      right: 9%;
      top: -160px;
      background: var(--violet);
      opacity: .9;
    }
    .hero::after {
      width: 160px;
      height: 360px;
      right: 2%;
      bottom: -150px;
      background: var(--coral);
    }
    .hero-grid {
      position: relative;
      z-index: 1;
      display: grid;
      grid-template-columns: minmax(0, 1.12fr) minmax(310px, .88fr);
      align-items: center;
      gap: 64px;
    }
    .hero .eyebrow { color: var(--yellow); }
    .hero .lead { color: #d8def5; }
    .hero-actions { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 30px; }
    .hero-visual {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 12px;
    }
    .metric-box {
      min-height: 145px;
      padding: 22px;
      border: 1px solid rgba(255,255,255,.2);
      background: rgba(255,255,255,.09);
      border-radius: 12px;
      animation: rise .7s both;
    }
    .metric-box:nth-child(2) { margin-top: 28px; animation-delay: .12s; }
    .metric-box:nth-child(3) { animation-delay: .22s; }
    .metric-box:nth-child(4) { margin-top: 28px; animation-delay: .32s; }
    .metric-box strong { display: block; color: var(--yellow); font-size: 31px; line-height: 1.1; }
    .metric-box span { display: block; margin-top: 9px; color: #e9edff; font-size: 14px; }

    .intro-band { background: #f3f5ff; }
    .intro-grid, .split-grid {
      display: grid;
      grid-template-columns: repeat(2, minmax(0, 1fr));
      gap: 48px;
      align-items: start;
    }
    .feature-list { display: grid; gap: 13px; margin: 0; padding: 0; list-style: none; }
    .feature-list li {
      padding: 16px 18px 16px 48px;
      position: relative;
      background: #fff;
      border-left: 4px solid var(--mint);
      box-shadow: 0 7px 22px rgba(52, 63, 109, .06);
    }
    .feature-list li::before {
      content: "✓";
      position: absolute;
      left: 18px;
      color: var(--mint);
      font-weight: 900;
    }
    .service-grid { display: grid; grid-template-columns: repeat(4, minmax(0,1fr)); gap: 16px; }
    .service-card {
      padding: 24px 20px;
      background: var(--panel);
      border: 1px solid var(--line);
      border-top: 4px solid var(--violet);
      border-radius: var(--radius);
      transition: transform .25s ease, box-shadow .25s ease;
    }
    .service-card:nth-child(4n+2) { border-top-color: var(--coral); }
    .service-card:nth-child(4n+3) { border-top-color: var(--mint); }
    .service-card:nth-child(4n+4) { border-top-color: var(--yellow); }
    .service-card:hover { transform: translateY(-6px); box-shadow: var(--shadow); }
    .service-card p { color: var(--muted); font-size: 14px; margin-bottom: 0; }
    .service-tag {
      display: inline-block;
      margin-bottom: 18px;
      padding: 4px 9px;
      color: var(--blue);
      background: #eef1ff;
      border-radius: 5px;
      font-size: 12px;
      font-weight: 800;
    }
    .workflow { background: #fff4ef; }
    .steps { display: grid; grid-template-columns: repeat(5, 1fr); gap: 14px; }
    .step { position: relative; padding: 24px 20px; background: #fff; border-radius: 12px; }
    .step-number {
      display: grid;
      place-items: center;
      width: 36px;
      height: 36px;
      margin-bottom: 22px;
      color: #fff;
      background: var(--coral);
      border-radius: 50%;
      font-weight: 900;
    }
    .step p { color: var(--muted); font-size: 14px; margin-bottom: 0; }
    .network-wrap {
      display: flex;
      flex-wrap: wrap;
      gap: 10px;
      padding: 26px;
      background: var(--navy);
      border-radius: 14px;
    }
    .network-wrap span {
      padding: 8px 12px;
      color: #fff;
      background: rgba(255,255,255,.1);
      border: 1px solid rgba(255,255,255,.13);
      border-radius: 5px;
      font-size: 14px;
    }
    .network-wrap span:nth-child(3n) { color: var(--yellow); }
    .network-wrap span:nth-child(4n) { color: #72e7cd; }
    .table-shell { overflow-x: auto; border: 1px solid var(--line); border-radius: 12px; background: #fff; }
    table { width: 100%; min-width: 720px; border-collapse: collapse; }
    th, td { padding: 17px 18px; text-align: left; border-bottom: 1px solid var(--line); }
    th { color: #fff; background: var(--blue); font-size: 14px; }
    td { color: var(--muted); font-size: 14px; }
    td:first-child { color: var(--ink); font-weight: 800; }
    tr:last-child td { border-bottom: 0; }
    .score-card {
      padding: 30px;
      color: #fff;
      background: var(--violet);
      border-radius: 14px;
    }
    .score-card strong { display: block; color: var(--yellow); font-size: 62px; line-height: 1; }
    .stars { color: var(--yellow); letter-spacing: 5px; font-size: 24px; margin: 12px 0; }
    .case-grid, .review-grid, .article-grid { display: grid; grid-template-columns: repeat(3, minmax(0,1fr)); gap: 18px; }
    .case-card, .review-card, .article-card {
      background: #fff;
      border: 1px solid var(--line);
      border-radius: 12px;
      overflow: hidden;
      transition: transform .25s ease, box-shadow .25s ease;
    }
    .case-card:hover, .review-card:hover, .article-card:hover { transform: translateY(-5px); box-shadow: var(--shadow); }
    .case-image { aspect-ratio: 16 / 8; overflow: hidden; background: #eef1ff; }
    .case-image img { width: 100%; height: 100%; object-fit: cover; }
    .case-body, .review-card, .article-card { padding: 22px; }
    .case-body p, .review-card p, .article-card p { color: var(--muted); font-size: 14px; margin-bottom: 0; }
    .review-card { border-top: 4px solid var(--mint); }
    .review-card:nth-child(2n) { border-top-color: var(--coral); }
    .review-card:nth-child(3n) { border-top-color: var(--violet); }
    .review-user { display: flex; align-items: center; gap: 12px; margin-bottom: 16px; }
    .avatar { display: grid; place-items: center; width: 42px; height: 42px; color: #fff; background: var(--blue); border-radius: 50%; font-weight: 900; }
    .review-user strong { display: block; }
    .review-user small { color: var(--muted); }
    .faq-list { display: grid; gap: 10px; max-width: 900px; }
    .faq-item { background: #fff; border: 1px solid var(--line); border-radius: 9px; }
    .faq-item summary { padding: 18px 22px; cursor: pointer; font-weight: 800; list-style: none; }
    .faq-item summary::-webkit-details-marker { display: none; }
    .faq-item summary::after { content: "+"; float: right; color: var(--blue); font-size: 22px; line-height: 1; }
    .faq-item[open] summary::after { content: "−"; }
    .faq-answer { padding: 0 22px 18px; color: var(--muted); font-size: 14px; }
    .article-card a { display: inline-block; margin-top: 16px; color: var(--blue); font-weight: 800; }
    .article-card a::after { content: " →"; }
    .tag-cloud { display: flex; flex-wrap: wrap; gap: 10px; }
    .tag-cloud span { padding: 9px 14px; color: #27324c; background: #fff; border: 1px solid #dde2f5; border-radius: 5px; font-size: 14px; }
    .contact-section { background: #eaf8f4; }
    .form-panel { padding: 30px; background: #fff; border-radius: 14px; box-shadow: var(--shadow); }
    .form-grid { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 16px; }
    .field { display: grid; gap: 7px; }
    .field.full { grid-column: 1 / -1; }
    label { color: var(--ink); font-size: 14px; font-weight: 800; }
    input, select, textarea {
      width: 100%;
      padding: 13px 14px;
      color: var(--ink);
      background: #fbfcff;
      border: 1px solid #dfe3ec;
      border-radius: 7px;
      outline: none;
    }
    input:focus, select:focus, textarea:focus { border-color: var(--blue); box-shadow: 0 0 0 3px rgba(49,85,231,.1); }
    textarea { min-height: 125px; resize: vertical; }
    .contact-info { display: grid; gap: 16px; }
    .contact-box { padding: 20px; background: #fff; border-left: 4px solid var(--coral); border-radius: 8px; }
    .contact-box p { margin: 0; color: var(--muted); }
    .qr { width: 130px; margin-top: 12px; }
    .join-band { background: var(--yellow); }
    .join-inner { display: flex; align-items: center; justify-content: space-between; gap: 25px; }
    .join-inner p { margin-bottom: 0; color: #4c3c00; }
    footer { padding: 48px 0 24px; color: #d8def5; background: var(--navy); }
    .footer-grid { display: grid; grid-template-columns: 1.3fr 1fr 1fr 1fr; gap: 30px; }
    footer h3 { color: #fff; font-size: 17px; }
    footer p, footer li, footer a { color: #aeb9d8; font-size: 14px; }
    footer ul { list-style: none; padding: 0; margin: 0; display: grid; gap: 7px; }
    footer a:hover { color: var(--yellow); }
    .footer-bottom { margin-top: 35px; padding-top: 18px; border-top: 1px solid rgba(255,255,255,.14); font-size: 13px; color: #8f9abb; }
    .float-contact, .back-top {
      position: fixed;
      right: 22px;
      z-index: 15;
      display: grid;
      place-items: center;
      border: 0;
      cursor: pointer;
      box-shadow: 0 10px 25px rgba(16,25,52,.2);
    }
    .float-contact { bottom: 80px; width: 52px; height: 52px; color: #fff; background: var(--coral); border-radius: 50%; font-size: 22px; }
    .back-top { right: 24px; bottom: 20px; width: 38px; height: 38px; color: var(--navy); background: var(--yellow); border-radius: 8px; opacity: 0; pointer-events: none; transition: opacity .2s; }
    .back-top.show { opacity: 1; pointer-events: auto; }
    .reveal { opacity: 0; transform: translateY(20px); transition: opacity .65s ease, transform .65s ease; }
    .reveal.visible { opacity: 1; transform: none; }
    @keyframes rise { from { opacity: 0; transform: translateY(18px); } to { opacity: 1; transform: none; } }

    @media (max-width: 1020px) {
      .nav-links a { padding-left: 6px; padding-right: 6px; font-size: 12px; }
      .nav-cta { display: none; }
      .service-grid { grid-template-columns: repeat(2, minmax(0,1fr)); }
      .steps { grid-template-columns: repeat(3, 1fr); }
    }
    @media (max-width: 760px) {
      .container { width: min(100% - 28px, 600px); }
      .section { padding: 64px 0; }
      .menu-toggle { display: block; }
      .nav-links {
        display: none;
        position: absolute;
        left: 14px;
        right: 14px;
        top: 68px;
        padding: 10px;
        background: #fff;
        border: 1px solid var(--line);
        box-shadow: var(--shadow);
        border-radius: 10px;
      }
      .nav-links.open { display: grid; grid-template-columns: repeat(2, 1fr); }
      .nav-links a { padding: 10px 12px; }
      .hero { padding: 70px 0 55px; }
      .hero-grid, .intro-grid, .split-grid { grid-template-columns: 1fr; gap: 34px; }
      .hero-visual { max-width: 500px; }
      .service-grid, .steps, .case-grid, .review-grid, .article-grid { grid-template-columns: 1fr; }
      .form-grid { grid-template-columns: 1fr; }
      .field.full { grid-column: auto; }
      .join-inner { align-items: flex-start; flex-direction: column; }
      .footer-grid { grid-template-columns: repeat(2, 1fr); }
    }
    @media (max-width: 430px) {
      .hero-visual { grid-template-columns: 1fr 1fr; }
      .metric-box { min-height: 125px; padding: 16px; }
      .metric-box strong { font-size: 25px; }
      .footer-grid { grid-template-columns: 1fr; }
    }