/* roulang page: index */
:root {
      --primary-dark: #0A1929;
      --accent-green: #00E676;
      --accent-red: #FF1744;
      --bg-light: #F5F7FA;
      --bg-white: #FFFFFF;
      --text-dark: #1E293B;
      --text-body: #334155;
      --text-muted: #64748B;
      --text-light-gray: #94A3B8;
      --border-light: rgba(10, 25, 41, 0.06);
      --border-medium: #E2E8F0;
      --shadow-sm: 0 2px 8px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.08);
      --shadow-lg: 0 16px 40px rgba(10,25,41,0.12);
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-lg: 16px;
      --radius-xl: 24px;
      --font-sans: -apple-system, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --font-mono: 'Inter', system-ui, -apple-system, sans-serif;
      --spacing-section: 5rem;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg-light);
      color: var(--text-body);
      line-height: 1.75;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
      overflow-x: hidden;
    }

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

    a {
      text-decoration: none;
      color: inherit;
    }

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 0.5rem;
      transition: all 0.2s ease;
    }

    .container {
      width: 100%;
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 2rem;
    }

    /* 导航 */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      height: 72px;
      display: flex;
      align-items: center;
      box-shadow: 0 2px 20px rgba(0,0,0,0.06);
    }

    .header-inner {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }

    .logo {
      font-weight: 800;
      font-size: 1.75rem;
      letter-spacing: -0.02em;
      color: var(--primary-dark);
      display: flex;
      align-items: baseline;
    }
    .logo span {
      color: var(--accent-green);
    }

    .nav-menu {
      display: flex;
      gap: 2.25rem;
      list-style: none;
      align-items: center;
    }
    .nav-menu a {
      font-weight: 500;
      color: #475569;
      padding-bottom: 6px;
      border-bottom: 2px solid transparent;
      transition: 0.2s;
      font-size: 0.95rem;
    }
    .nav-menu a:hover {
      color: var(--primary-dark);
      border-bottom-color: var(--accent-green);
    }

    .btn-primary {
      background: var(--accent-red);
      color: white;
      padding: 0.7rem 1.8rem;
      border-radius: var(--radius-sm);
      font-weight: 600;
      font-size: 0.95rem;
      letter-spacing: 0.01em;
      box-shadow: 0 4px 12px rgba(255,23,68,0.2);
    }
    .btn-primary:hover {
      background: #D50000;
      transform: translateY(-2px);
      box-shadow: 0 8px 18px rgba(255,23,68,0.3);
    }

    .btn-outline {
      border: 1.5px solid var(--accent-green);
      color: var(--accent-green);
      background: transparent;
      padding: 0.7rem 1.8rem;
      border-radius: var(--radius-sm);
      font-weight: 600;
      font-size: 0.95rem;
    }
    .btn-outline:hover {
      background: rgba(0,230,118,0.08);
      transform: translateY(-2px);
    }

    .hamburger {
      display: none;
      font-size: 1.6rem;
      color: var(--primary-dark);
    }

    /* Hero */
    .hero-section {
      background: radial-gradient(circle at 30% 30%, rgba(0,230,118,0.06) 0%, transparent 60%);
      padding: 4rem 0 5rem;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 0.9fr;
      gap: 3rem;
      align-items: center;
    }
    .hero-title {
      font-size: clamp(2.25rem, 5vw, 3.5rem);
      font-weight: 800;
      line-height: 1.2;
      letter-spacing: -0.02em;
      color: var(--primary-dark);
      margin-bottom: 1.5rem;
    }
    .hero-title em {
      color: var(--accent-green);
      font-style: normal;
    }
    .hero-sub {
      font-size: 1.2rem;
      color: var(--text-muted);
      margin-bottom: 2.5rem;
      max-width: 90%;
    }
    .hero-buttons {
      display: flex;
      gap: 1rem;
      flex-wrap: wrap;
    }
    .hero-image img {
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-lg);
    }

    /* 痛点 */
    .pain-section {
      padding: var(--spacing-section) 0;
      background: var(--bg-white);
    }
    .pain-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 3rem;
      align-items: center;
    }
    .pain-list {
      display: flex;
      flex-direction: column;
      gap: 2rem;
    }
    .pain-item {
      display: flex;
      gap: 1rem;
      border-left: 4px solid var(--accent-red);
      padding-left: 1.5rem;
    }
    .pain-icon {
      color: var(--accent-red);
      font-size: 1.5rem;
      margin-top: 0.2rem;
    }
    .pain-text h4 {
      font-weight: 700;
      color: var(--text-dark);
      margin-bottom: 0.25rem;
    }
    .pain-image img {
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-md);
    }

    /* 解决方案 非对称 */
    .solution-section {
      padding: var(--spacing-section) 0;
    }
    .section-title {
      font-size: clamp(1.75rem, 3.5vw, 2.25rem);
      font-weight: 700;
      color: var(--primary-dark);
      margin-bottom: 3rem;
      text-align: center;
    }
    .solution-grid {
      display: grid;
      grid-template-columns: 2fr 1fr;
      gap: 1.5rem;
      margin-bottom: 1.5rem;
    }
    .solution-grid-bottom {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 1.5rem;
    }
    .solution-card {
      background: white;
      border-radius: var(--radius-lg);
      padding: 2rem;
      box-shadow: var(--shadow-sm);
      border: 1px solid var(--border-light);
      transition: 0.25s;
      display: flex;
      flex-direction: column;
      gap: 0.8rem;
    }
    .solution-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-lg);
    }
    .solution-icon {
      width: 48px;
      height: 48px;
      background: rgba(0,230,118,0.12);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--accent-green);
      font-size: 1.5rem;
    }
    .solution-card h3 {
      font-size: 1.25rem;
      font-weight: 600;
      color: var(--primary-dark);
    }

    /* 数据区 */
    .stats-section {
      background: var(--primary-dark);
      padding: 4rem 0;
      color: white;
      position: relative;
      overflow: hidden;
    }
    .stats-section::before {
      content: "";
      position: absolute;
      inset: 0;
      background-image: repeating-linear-gradient(45deg, rgba(255,255,255,0.02) 0px, rgba(255,255,255,0.02) 2px, transparent 2px, transparent 8px);
      pointer-events: none;
    }
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 2rem;
      text-align: center;
      position: relative;
    }
    .stat-number {
      font-family: var(--font-mono);
      font-size: 2.8rem;
      font-weight: 700;
      color: var(--accent-green);
      line-height: 1.2;
    }
    .stat-label {
      color: #CBD5E1;
      margin-top: 0.5rem;
    }
    .stat-divider {
      width: 1px;
      background: rgba(255,255,255,0.15);
      margin: 0 auto;
    }

    /* 证言 */
    .testimonial-section {
      padding: var(--spacing-section) 0;
      background: var(--bg-white);
    }
    .testimonial-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 2rem;
    }
    .testimonial-card {
      background: #F8FAFC;
      border-radius: var(--radius-md);
      padding: 2rem;
      display: flex;
      gap: 1.5rem;
      align-items: flex-start;
    }
    .avatar {
      width: 64px;
      height: 64px;
      border-radius: 50%;
      border: 3px solid var(--accent-green);
      object-fit: cover;
    }
    .stars {
      color: var(--accent-green);
      margin-bottom: 0.5rem;
    }
    .testimonial-text {
      font-style: italic;
      color: var(--text-body);
      margin-bottom: 0.5rem;
    }

    /* FAQ */
    .faq-section {
      padding: var(--spacing-section) 0;
    }
    .faq-item {
      border-bottom: 1px solid var(--border-medium);
    }
    .faq-question {
      width: 100%;
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 1.3rem 0;
      font-weight: 600;
      color: var(--text-dark);
      font-size: 1.1rem;
      background: transparent;
      border: none;
      cursor: pointer;
      text-align: left;
    }
    .faq-question i {
      transition: transform 0.2s;
      color: var(--text-muted);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s;
      color: #475569;
      padding: 0 0;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 1.3rem;
    }
    .faq-item.active .faq-question {
      color: var(--accent-green);
    }
    .faq-item.active .faq-question i {
      transform: rotate(45deg);
      color: var(--accent-green);
    }

    /* 终极CTA */
    .cta-section {
      background: var(--primary-dark);
      padding: 5rem 0;
      text-align: center;
      color: white;
    }
    .cta-title {
      font-size: clamp(2rem, 4vw, 2.8rem);
      font-weight: 800;
      margin-bottom: 1rem;
    }
    .cta-desc {
      color: #CBD5E1;
      margin-bottom: 2.5rem;
      font-size: 1.2rem;
    }
    .btn-xl {
      background: var(--accent-red);
      color: white;
      padding: 1rem 3rem;
      border-radius: 50px;
      font-weight: 700;
      font-size: 1.2rem;
      transition: 0.2s;
      box-shadow: 0 8px 24px rgba(255,23,68,0.35);
    }
    .btn-xl:hover {
      transform: scale(1.05);
      background: #D50000;
    }

    /* 页脚 */
    .footer {
      background: #0F1A2B;
      color: #CBD5E1;
      padding: 3rem 0 2rem;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 2rem;
    }
    .footer-brand p {
      margin-top: 0.5rem;
      font-size: 0.95rem;
    }
    .footer-links a {
      display: block;
      margin-bottom: 0.4rem;
      color: #94A3B8;
    }
    .social-icons i {
      font-size: 1.5rem;
      margin-right: 1rem;
      color: #94A3B8;
    }
    .copyright {
      text-align: center;
      margin-top: 2.5rem;
      color: var(--text-light-gray);
      font-size: 0.9rem;
    }

    @media (max-width: 1024px) {
      .hero-grid { grid-template-columns: 1fr; }
      .pain-grid { grid-template-columns: 1fr; }
      .solution-grid, .solution-grid-bottom { grid-template-columns: 1fr; }
    }
    @media (max-width: 768px) {
      .nav-menu { display: none; }
      .hamburger { display: block; }
      .stats-grid { grid-template-columns: 1fr 1fr; }
      .testimonial-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }
    @media (max-width: 520px) {
      .stats-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr; }
      .hero-buttons { flex-direction: column; }
    }

    .mobile-menu {
      display: none;
      position: fixed;
      inset: 0;
      background: white;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      gap: 2rem;
      z-index: 100;
      font-size: 1.5rem;
    }
    .mobile-menu.open {
      display: flex;
    }