/* roulang page: index */
:root {
      --deep-blue: #0B1A2F;
      --electric-cyan: #00E5FF;
      --rock-gray: #2C3A4B;
      --silver-white: #F4F6F9;
      --warm-amber: #FF6F00;
      --text-primary: #1E293B;
      --text-secondary: #64748B;
      --border-light: #E2E8F0;
      --card-bg: #FFFFFF;
      --card-bg-alt: #FAFBFC;
      --shadow-sm: 0 4px 20px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 30px rgba(0,0,0,0.08);
      --radius-lg: 12px;
      --radius-md: 8px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", system-ui, sans-serif;
      --transition-base: 0.25s ease;
    }

    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }

    body {
      font-family: var(--font-sans);
      background-color: var(--silver-white);
      color: var(--text-primary);
      line-height: 1.7;
      font-size: 16px;
      font-weight: 400;
    }

    img {
      max-width: 100%;
      height: auto;
      display: block;
    }

    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition-base);
    }

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-weight: 600;
      border-radius: var(--radius-md);
      transition: all 0.2s ease;
      letter-spacing: 0.3px;
    }

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

    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 100;
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(10px);
      transition: background 0.3s ease, box-shadow 0.3s ease;
      border-bottom: 1px solid transparent;
    }
    .header.scrolled {
      background: #ffffff;
      box-shadow: 0 2px 12px rgba(0,0,0,0.04);
      border-bottom: 1px solid var(--border-light);
    }
    .nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 70px;
    }
    .logo {
      display: flex;
      align-items: center;
      font-weight: 700;
      font-size: 1.5rem;
      color: var(--deep-blue);
      gap: 8px;
    }
    .logo-icon {
      width: 8px;
      height: 8px;
      background: var(--electric-cyan);
      border-radius: 2px;
      box-shadow: 0 0 10px var(--electric-cyan);
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-links a {
      font-weight: 500;
      color: var(--text-primary);
      font-size: 0.95rem;
      position: relative;
    }
    .nav-links a:hover {
      color: var(--electric-cyan);
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--electric-cyan);
      transition: 0.2s;
    }
    .nav-links a:hover::after {
      width: 100%;
    }
    .btn-primary {
      background: var(--electric-cyan);
      color: var(--deep-blue);
      padding: 12px 28px;
      font-weight: 600;
      box-shadow: 0 4px 12px rgba(0,229,255,0.3);
    }
    .btn-primary:hover {
      filter: brightness(1.08);
      transform: scale(1.02);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--electric-cyan);
      color: var(--electric-cyan);
      padding: 12px 28px;
    }
    .btn-outline:hover {
      background: rgba(0,229,255,0.08);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
    }
    .hamburger span {
      width: 25px;
      height: 2px;
      background: var(--deep-blue);
      transition: 0.2s;
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100vh;
      background: #ffffff;
      z-index: 99;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 36px;
    }
    .mobile-menu a {
      font-size: 1.5rem;
      font-weight: 600;
      color: var(--deep-blue);
    }
    .close-btn {
      position: absolute;
      top: 30px;
      right: 30px;
      font-size: 2rem;
      color: var(--electric-cyan);
      background: none;
      border: none;
    }

    /* Hero */
    .hero {
      padding: 140px 0 100px;
      background: linear-gradient(135deg, var(--deep-blue) 0%, #122b44 100%);
      color: white;
      min-height: 80vh;
      display: flex;
      align-items: center;
      position: relative;
      overflow: hidden;
    }
    .hero::before {
      content: '';
      position: absolute;
      right: 0;
      bottom: 0;
      width: 50%;
      height: 100%;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      opacity: 0.25;
      mask-image: linear-gradient(to left, black 30%, transparent);
    }
    .hero-content {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 40px;
      position: relative;
      z-index: 2;
    }
    .hero-text {
      flex: 1;
    }
    .hero h1 {
      font-size: 3rem;
      font-weight: 700;
      line-height: 1.3;
      letter-spacing: -0.5px;
      margin-bottom: 24px;
      color: white;
    }
    .hero-sub {
      font-size: 1.2rem;
      color: rgba(255,255,255,0.75);
      margin-bottom: 36px;
      max-width: 500px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-visual {
      flex: 1;
      display: flex;
      justify-content: flex-end;
    }
    .data-graphic {
      width: 300px;
      height: 300px;
      border: 2px solid rgba(0,229,255,0.3);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      background: rgba(255,255,255,0.03);
      backdrop-filter: blur(4px);
      position: relative;
    }
    .data-graphic span {
      font-size: 2.5rem;
      font-weight: 800;
      color: var(--electric-cyan);
      text-shadow: 0 0 12px rgba(0,229,255,0.6);
    }

    section {
      padding: 100px 0;
    }

    .section-title {
      font-size: 2rem;
      font-weight: 600;
      margin-bottom: 16px;
      color: var(--deep-blue);
    }
    .section-sub {
      color: var(--text-secondary);
      margin-bottom: 48px;
    }

    /* 痛点 */
    .pain-grid {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 32px;
    }
    .pain-card {
      background: var(--card-bg);
      padding: 32px 24px;
      border-radius: var(--radius-lg);
      border-bottom: 2px solid transparent;
      transition: var(--transition-base);
      box-shadow: var(--shadow-sm);
    }
    .pain-card:hover {
      border-bottom-color: var(--electric-cyan);
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    .pain-icon {
      font-size: 2rem;
      color: var(--electric-cyan);
      margin-bottom: 16px;
    }

    /* 解决方案 */
    .solution-grid {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 32px;
    }
    .solution-card {
      background: var(--card-bg);
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-sm);
      overflow: hidden;
      transition: var(--transition-base);
      border: 1px solid var(--border-light);
    }
    .solution-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
      border-color: var(--electric-cyan);
    }
    .solution-img {
      height: 180px;
      background-size: cover;
      background-position: center;
    }
    .solution-body {
      padding: 28px;
    }
    .solution-body h3 {
      margin-bottom: 12px;
    }

    /* 数据成果 */
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      gap: 24px;
    }
    .stat-item {
      text-align: center;
    }
    .stat-number {
      font-size: 3rem;
      font-weight: 800;
      color: var(--electric-cyan);
    }
    .stat-label {
      color: var(--text-secondary);
    }

    /* 证言 */
    .testimonial-grid {
      display: grid;
      grid-template-columns: repeat(2,1fr);
      gap: 32px;
    }
    .testimonial-card {
      background: var(--card-bg-alt);
      padding: 32px;
      border-radius: var(--radius-lg);
      display: flex;
      gap: 20px;
    }
    .avatar {
      width: 56px;
      height: 56px;
      background: var(--rock-gray);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-weight: 700;
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 20px 0;
    }
    .faq-question {
      font-weight: 600;
      font-size: 1.1rem;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: 0.3s;
      color: var(--text-secondary);
    }
    .faq-item.active .faq-answer {
      max-height: 150px;
      margin-top: 12px;
    }

    /* CTA */
    .cta-section {
      background: var(--deep-blue);
      color: white;
      text-align: center;
      padding: 100px 0;
    }
    .cta-section h2 {
      color: white;
    }

    footer {
      background: var(--deep-blue);
      color: #ccc;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 30px;
    }

    @media (max-width: 1024px) {
      .hero h1 { font-size: 2.5rem; }
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .hero-content { flex-direction: column; }
      .pain-grid, .solution-grid, .stats-grid { grid-template-columns: 1fr; }
      .testimonial-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr; }
      section { padding: 60px 0; }
    }