/* roulang page: index */
:root {
      --primary-deep: #0A0E17;
      --accent-red: #E63916;
      --accent-red-hover: #C62D0F;
      --metal-gold: #B69D74;
      --bg-warm: #F5F2EB;
      --dark-block: #1C212B;
      --card-bg: #FFFFFF;
      --card-border: #E8E5DF;
      --text-main: #1A1D23;
      --text-secondary: #4A4E57;
      --text-on-dark: #F0F0F0;
      --shadow-sm: 0 4px 20px rgba(10,14,23,0.06);
      --shadow-hover: 0 12px 28px rgba(10,14,23,0.12);
      --radius-sm: 8px;
      --radius-lg: 12px;
      --radius-btn: 4px;
      --font-heading: 'Noto Sans SC', system-ui, -apple-system, 'Segoe UI', sans-serif;
      --font-number: 'Oswald', 'Impact', 'Arial Black', sans-serif;
      --transition: 0.25s ease;
    }
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      font-family: 'Noto Sans SC', system-ui, -apple-system, sans-serif;
      background-color: var(--bg-warm);
      color: var(--text-main);
      line-height: 1.8;
      font-weight: 400;
      overflow-x: hidden;
    }
    .container {
      width: 100%;
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 32px;
    }
    @media (max-width: 768px) {
      .container {
        padding: 0 20px;
      }
    }
    /* 导航栏 */
    .main-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(10, 14, 23, 0.92);
      backdrop-filter: blur(8px);
      z-index: 1000;
      border-bottom: 1px solid rgba(255,255,255,0.05);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 32px;
    }
    .logo {
      font-family: var(--font-heading);
      font-weight: 900;
      font-size: 1.8rem;
      letter-spacing: -0.02em;
      color: #ffffff;
      text-decoration: none;
      display: flex;
      align-items: center;
      gap: 6px;
    }
    .logo i {
      color: var(--accent-red);
      font-size: 1.9rem;
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
      list-style: none;
    }
    .nav-links a {
      color: #ddd;
      text-decoration: none;
      font-weight: 500;
      font-size: 1rem;
      transition: color var(--transition);
      letter-spacing: 0.3px;
      position: relative;
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--accent-red);
    }
    .hamburger {
      display: none;
      background: none;
      border: none;
      color: white;
      font-size: 1.8rem;
      cursor: pointer;
    }
    @media (max-width: 768px) {
      .nav-links {
        position: fixed;
        top: 72px;
        left: 0;
        width: 100%;
        height: calc(100vh - 72px);
        background: #0A0E17;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: 40px;
        transform: translateX(100%);
        transition: transform 0.3s ease;
        z-index: 999;
      }
      .nav-links.open {
        transform: translateX(0);
      }
      .nav-links a {
        font-size: 1.5rem;
        font-weight: 700;
      }
      .hamburger {
        display: block;
      }
    }
    /* 板块间距 */
    .section {
      padding: 100px 0;
    }
    @media (max-width: 768px) {
      .section {
        padding: 60px 0;
      }
    }
    /* Hero */
    .hero {
      background-color: var(--primary-deep);
      position: relative;
      min-height: 100vh;
      display: flex;
      align-items: center;
      color: white;
      overflow: hidden;
    }
    .hero::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;
    }
    .hero .container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 40px;
      flex-wrap: wrap;
      position: relative;
      z-index: 2;
    }
    .hero-text {
      flex: 1 1 450px;
    }
    .hero h1 {
      font-family: var(--font-heading);
      font-weight: 900;
      font-size: 3.5rem;
      line-height: 1.2;
      letter-spacing: -0.02em;
      margin-bottom: 1.5rem;
      color: #fff;
    }
    .hero h1 span {
      color: var(--accent-red);
    }
    .hero p {
      font-size: 1.2rem;
      color: #ccc;
      margin-bottom: 2rem;
      max-width: 500px;
    }
    .hero-visual {
      flex: 1 1 400px;
      display: flex;
      justify-content: center;
      align-items: center;
    }
    .hero-visual img {
      max-width: 100%;
      height: auto;
      filter: drop-shadow(0 20px 30px rgba(0,0,0,0.5));
      opacity: 0.9;
    }
    .btn-group {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--accent-red);
      color: white;
      font-weight: 700;
      padding: 14px 32px;
      border: none;
      border-radius: var(--radius-btn);
      font-size: 1rem;
      letter-spacing: 0.5px;
      cursor: pointer;
      transition: background var(--transition), transform 0.2s;
      text-decoration: none;
      display: inline-block;
    }
    .btn-primary:hover {
      background: var(--accent-red-hover);
      transform: scale(1.02);
    }
    .btn-secondary {
      background: transparent;
      color: var(--accent-red);
      border: 2px solid var(--accent-red);
      font-weight: 700;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-size: 1rem;
      cursor: pointer;
      transition: background var(--transition), color var(--transition);
      text-decoration: none;
    }
    .btn-secondary:hover {
      background: rgba(230,57,22,0.1);
    }
    @media (max-width: 768px) {
      .hero h1 {
        font-size: 2.4rem;
      }
      .hero .container {
        flex-direction: column;
        text-align: center;
      }
      .hero-visual {
        order: -1;
      }
    }
    /* 核心优势 */
    .features-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 40px;
    }
    .feature-item {
      display: flex;
      gap: 24px;
      align-items: flex-start;
    }
    .feature-number {
      font-family: var(--font-number);
      font-size: 3rem;
      font-weight: 700;
      color: var(--accent-red);
      line-height: 1;
      min-width: 70px;
    }
    .feature-content h3 {
      font-family: var(--font-heading);
      font-weight: 700;
      font-size: 1.5rem;
      margin-bottom: 0.5rem;
    }
    @media (max-width: 768px) {
      .features-grid {
        grid-template-columns: 1fr;
      }
    }
    /* 产品卡片 */
    .product-cards {
      display: flex;
      flex-direction: column;
      gap: 32px;
    }
    .product-card {
      background: var(--card-bg);
      border: 1px solid var(--card-border);
      border-radius: var(--radius-lg);
      padding: 32px;
      display: flex;
      gap: 32px;
      box-shadow: var(--shadow-sm);
      transition: all var(--transition);
      border-left: 4px solid var(--metal-gold);
    }
    .product-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }
    .product-icon {
      font-size: 2.5rem;
      color: var(--metal-gold);
      min-width: 60px;
    }
    @media (max-width: 768px) {
      .product-card {
        flex-direction: column;
      }
    }
    /* 场景 */
    .scenario-row {
      display: flex;
      align-items: center;
      gap: 60px;
      margin-bottom: 60px;
    }
    .scenario-row.reverse {
      flex-direction: row-reverse;
    }
    .scenario-img img {
      width: 100%;
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-sm);
    }
    @media (max-width: 768px) {
      .scenario-row, .scenario-row.reverse {
        flex-direction: column;
      }
    }
    /* 案例卡片 */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
      gap: 24px;
    }
    .case-card {
      background: var(--card-bg);
      border-radius: var(--radius-lg);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
    }
    .case-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }
    .case-card img {
      width: 100%;
      height: 200px;
      object-fit: cover;
    }
    .case-body {
      padding: 24px;
    }
    .stat {
      font-family: var(--font-number);
      font-size: 2rem;
      color: var(--accent-red);
    }
    /* FAQ */
    .faq-item {
      border-bottom: 1px solid #ddd;
      padding: 18px 0;
      cursor: pointer;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      font-weight: 700;
      font-size: 1.1rem;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: #4a4a4a;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      margin-top: 12px;
    }
    /* CTA */
    .dark-cta {
      background: var(--dark-block);
      color: white;
      text-align: center;
    }
    .dark-cta h2 {
      font-size: 2.5rem;
      margin-bottom: 1rem;
    }
    /* 页脚 */
    .footer {
      background: var(--dark-block);
      color: #bbb;
      padding: 40px 0;
    }
    .footer-content {
      display: flex;
      justify-content: space-between;
      flex-wrap: wrap;
      gap: 20px;
      border-top: 1px solid var(--metal-gold);
      padding-top: 32px;
    }