/* roulang page: index */
:root {
      --deep-charcoal: #1A1F2B;
      --electric-cyan: #00E5FF;
      --warm-amber: #FFB74D;
      --surface-light: #F8F9FC;
      --white: #ffffff;
      --text-primary: #1A1F2B;
      --text-secondary: #5A6070;
      --text-muted: #8A92A3;
      --border-light: #E2E6ED;
      --radius-card: 8px;
      --radius-btn: 24px;
      --shadow-sm: 0 4px 10px rgba(0, 0, 0, 0.04);
      --shadow-md: 0 12px 28px rgba(0, 0, 0, 0.07);
      --shadow-glow: 0 0 16px rgba(0, 229, 255, 0.45);
      --transition-fast: 0.2s ease;
      --transition-smooth: 0.3s cubic-bezier(0.25, 0.8, 0.25, 1.2);
      --font-sans: 'Inter', 'Noto Sans SC', system-ui, -apple-system, 'Segoe UI', sans-serif;
    }
    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
    html { scroll-behavior: smooth; }
    body {
      font-family: var(--font-sans);
      background-color: var(--white);
      color: var(--text-primary);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    img { max-width: 100%; height: auto; display: block; }
    a { text-decoration: none; color: inherit; }
    button { font-family: inherit; cursor: pointer; border: none; background: none; }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }

    /* 导航 */
    .nb-header {
      position: fixed; top: 0; left: 0; width: 100%; height: 64px;
      background: var(--deep-charcoal); z-index: 50;
      display: flex; align-items: center; justify-content: space-between;
      padding: 0 32px; box-shadow: 0 2px 8px rgba(0,0,0,0.15);
    }
    .nb-logo {
      font-weight: 700; font-size: 22px; letter-spacing: 2px;
      color: #ffffff; white-space: nowrap;
    }
    .nb-nav-links { display: flex; gap: 32px; align-items: center; }
    .nb-nav-links a {
      color: rgba(255,255,255,0.72); font-weight: 500; font-size: 15px;
      padding: 6px 0; position: relative; transition: color var(--transition-fast);
    }
    .nb-nav-links a::after {
      content: ''; position: absolute; bottom: 0; left: 0; width: 100%; height: 2px;
      background: var(--electric-cyan); transform: scaleX(0); transition: transform var(--transition-fast);
      box-shadow: 0 0 8px var(--electric-cyan);
    }
    .nb-nav-links a:hover,
    .nb-nav-links a.active { color: var(--electric-cyan); }
    .nb-nav-links a:hover::after,
    .nb-nav-links a.active::after { transform: scaleX(1); }
    .nb-cta-btn {
      background: var(--electric-cyan); color: #0a0c12; font-weight: 700;
      padding: 10px 22px; border-radius: var(--radius-btn); margin-left: 16px;
      transition: background var(--transition-fast), box-shadow var(--transition-fast);
      font-size: 15px; letter-spacing: 0.4px;
    }
    .nb-cta-btn:hover { background: #33eaff; box-shadow: 0 0 16px var(--electric-cyan); }
    .hamburger { display: none; flex-direction: column; gap: 5px; cursor: pointer; }
    .hamburger span { width: 24px; height: 2.5px; background: #fff; border-radius: 2px; }

    @media (max-width: 768px) {
      .nb-nav-links { display: none; }
      .hamburger { display: flex; }
      .nb-header { padding: 0 20px; }
    }
    .mobile-menu {
      position: fixed; top: 0; left: 0; width: 100%; height: 100vh;
      background: rgba(18,22,28,0.96); z-index: 60; display: none;
      flex-direction: column; align-items: center; justify-content: center; gap: 32px;
    }
    .mobile-menu.active { display: flex; }
    .mobile-menu a {
      color: rgba(255,255,255,0.8); font-size: 20px; font-weight: 500;
    }

    /* Hero */
    .hero {
      min-height: 100vh; display: flex; align-items: center;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      position: relative; margin-top: 0;
    }
    .hero-overlay {
      position: absolute; inset: 0;
      background: linear-gradient(135deg, rgba(26,31,43,0.78) 0%, rgba(10,15,20,0.5) 100%);
    }
    .hero-content { position: relative; z-index: 2; width: 100%; }
    .hero h1 {
      font-size: 48px; font-weight: 700; line-height: 1.2; color: #ffffff;
      margin-bottom: 20px; max-width: 700px;
    }
    .hero .sub {
      font-size: 18px; color: rgba(255,255,255,0.8); margin-bottom: 36px; max-width: 540px;
    }
    .hero-buttons { display: flex; gap: 16px; flex-wrap: wrap; }
    .btn-primary {
      background: var(--electric-cyan); color: #0a0c12; font-weight: 700;
      padding: 14px 34px; border-radius: var(--radius-btn); font-size: 17px;
      transition: 0.25s; box-shadow: 0 4px 14px rgba(0,229,255,0.3);
    }
    .btn-primary:hover { background: #29f0ff; box-shadow: 0 0 22px var(--electric-cyan); }
    .btn-ghost {
      border: 1.5px solid rgba(255,255,255,0.7); color: #ffffff;
      padding: 14px 34px; border-radius: var(--radius-btn); font-weight: 600;
      backdrop-filter: blur(6px); transition: 0.25s;
    }
    .btn-ghost:hover { border-color: var(--electric-cyan); color: var(--electric-cyan); }

    @media (max-width: 640px) {
      .hero h1 { font-size: 32px; }
      .hero .sub { font-size: 16px; }
    }

    section { padding: 80px 0; }
    .section-title {
      font-size: 34px; font-weight: 700; margin-bottom: 16px; color: var(--deep-charcoal);
    }
    .section-sub { color: var(--text-secondary); font-size: 17px; margin-bottom: 48px; }

    .pain-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; align-items: center; }
    .pain-list { list-style: none; }
    .pain-list li { display: flex; gap: 14px; margin-bottom: 24px; font-size: 17px; align-items: flex-start; }
    .pain-icon { color: #e5573b; font-weight: 700; font-size: 20px; }

    .solution-cards {
      display: grid; grid-template-columns: repeat(3,1fr); gap: 24px;
    }
    .sol-card {
      background: #fff; border-radius: var(--radius-card); padding: 28px 20px;
      box-shadow: var(--shadow-sm); border-left: 4px solid var(--electric-cyan);
      transition: all var(--transition-smooth);
    }
    .sol-card:hover { box-shadow: var(--shadow-md); border-left-width: 6px; transform: translateY(-4px); }
    .sol-num { font-size: 28px; font-weight: 700; color: var(--electric-cyan); }

    .service-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 28px; }
    .service-card {
      background: #fff; border-radius: var(--radius-card); overflow: hidden;
      box-shadow: var(--shadow-sm); transition: transform var(--transition-smooth), box-shadow var(--transition-smooth);
    }
    .service-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-md); }
    .service-img { aspect-ratio: 16/9; background: #dce2ea; }
    .service-img img { width: 100%; height: 100%; object-fit: cover; }
    .service-text { padding: 22px 18px; }
    .service-link { color: var(--electric-cyan); font-weight: 600; margin-top: 8px; display: inline-block; border-bottom: 1.5px solid transparent; transition: 0.2s; }
    .service-link:hover { border-bottom-color: var(--electric-cyan); }

    .process-steps { display: flex; justify-content: space-between; text-align: center; position: relative; }
    .step { flex: 1; position: relative; }
    .step-circle {
      width: 56px; height: 56px; border: 2px solid var(--electric-cyan); border-radius: 50%;
      margin: 0 auto 16px; display: flex; align-items: center; justify-content: center;
      font-weight: 700; font-size: 22px; color: var(--electric-cyan); background: #fff;
    }
    .step-line { position: absolute; top: 28px; left: 60%; width: 80%; height: 2px; border-top: 2px dashed #cbd5e0; z-index: -1; }

    .stats-block {
      background: var(--deep-charcoal); color: #fff; padding: 70px 0; text-align: center;
    }
    .stat-number { font-size: 52px; font-weight: 700; color: var(--warm-amber); }

    .testimonial-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 24px; }
    .testimonial-card {
      background: #fff; border-radius: var(--radius-card); padding: 28px;
      box-shadow: var(--shadow-sm); position: relative;
    }
    .quote-mark { font-size: 36px; color: var(--electric-cyan); }

    .faq-item { margin-bottom: 16px; border: 1px solid var(--border-light); border-radius: var(--radius-card); }
    .faq-question {
      background: #fff; padding: 18px 24px; font-weight: 700; display: flex; justify-content: space-between;
      cursor: pointer; transition: background 0.2s;
    }
    .faq-answer { padding: 0 24px 18px; display: none; color: var(--text-secondary); }

    .cta-section {
      background: var(--deep-charcoal); color: #fff; text-align: center; padding: 80px 24px;
    }
    .cta-glow {
      background: var(--electric-cyan); color: #0a0c12; padding: 16px 42px;
      border-radius: 40px; font-weight: 700; font-size: 18px;
      box-shadow: 0 0 28px var(--electric-cyan); transition: 0.3s;
    }
    .cta-glow:hover { box-shadow: 0 0 44px var(--electric-cyan); }

    .footer {
      background: #12161C; color: #cbd5e0; padding: 50px 0 28px;
    }
    .footer-grid { display: grid; grid-template-columns: repeat(4,1fr); gap: 28px; }
    .footer a { color: #a0aec0; transition: 0.2s; }
    .footer a:hover { color: var(--electric-cyan); }

    @media (max-width: 1024px) {
      .solution-cards, .service-grid, .testimonial-grid { grid-template-columns: repeat(2,1fr); }
    }
    @media (max-width: 768px) {
      .pain-grid { grid-template-columns: 1fr; }
      .process-steps { flex-direction: column; gap: 28px; }
      .step-line { display: none; }
      .solution-cards, .service-grid, .testimonial-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }
    @media (max-width: 520px) {
      .footer-grid { grid-template-columns: 1fr; }
      section { padding: 56px 0; }
    }