/* roulang page: index */
:root {
      --primary: #E8451E;
      --primary-hover: #c93615;
      --primary-soft: rgba(232, 69, 30, 0.08);
      --gold: #D4A843;
      --dark: #1A1A1A;
      --gray-dark: #3A3A3A;
      --gray-mid: #6B6B6B;
      --light-bg: #F7F4EF;
      --white: #FFFFFF;
      --border-light: rgba(232, 69, 30, 0.12);
      --shadow-card: 0 4px 24px rgba(232, 69, 30, 0.08);
      --shadow-card-hover: 0 12px 32px rgba(232, 69, 30, 0.18);
      --shadow-nav: 0 2px 20px rgba(0,0,0,0.08);
      --radius-lg: 24px;
      --radius-md: 16px;
      --radius-sm: 12px;
      --radius-btn: 12px;
      --font-title: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      --font-body: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      --transition: 0.25s ease-in-out;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    html {
      scroll-behavior: smooth;
    }
    body {
      font-family: var(--font-body);
      color: var(--gray-dark);
      background: var(--white);
      line-height: 1.8;
      font-weight: 400;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 32px;
    }
    h1, h2, h3, .h2, .h3 {
      font-family: var(--font-title);
      font-weight: 700;
      letter-spacing: -0.02em;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color var(--transition);
    }
    img {
      max-width: 100%;
      display: block;
    }
    button, .btn {
      cursor: pointer;
      font-family: var(--font-body);
      font-weight: 600;
      transition: all var(--transition);
      border: none;
      outline: none;
    }
    /* 导航 */
    .nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      z-index: 1000;
      display: flex;
      align-items: center;
      transition: background 0.3s, box-shadow 0.3s;
    }
    .nav.scrolled {
      background: #FFFFFF;
      box-shadow: var(--shadow-nav);
    }
    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 800;
      font-size: 22px;
      color: var(--dark);
      letter-spacing: -0.5px;
    }
    .logo-icon {
      font-size: 28px;
      color: var(--primary);
      filter: drop-shadow(0 2px 6px rgba(232,69,30,0.5));
    }
    .nav-links {
      display: flex;
      gap: 36px;
      align-items: center;
      font-weight: 500;
    }
    .nav-links a {
      position: relative;
      padding: 8px 0;
      color: var(--gray-dark);
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--gold);
      transition: width 0.3s;
    }
    .nav-links a:hover::after {
      width: 100%;
    }
    .btn-primary-sm {
      background: var(--primary);
      color: white;
      padding: 10px 22px;
      border-radius: 30px;
      font-size: 15px;
      font-weight: 600;
      box-shadow: 0 4px 12px rgba(232,69,30,0.3);
      border: none;
      margin-left: 12px;
    }
    .btn-primary-sm:hover {
      background: #c93615;
      transform: scale(1.03);
    }
    .menu-toggle {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: transparent;
      border: none;
    }
    .menu-toggle span {
      width: 26px;
      height: 2px;
      background: var(--dark);
      transition: 0.3s;
    }
    .mobile-menu {
      display: none;
    }
    /* Hero */
    .hero {
      height: 100vh;
      background: linear-gradient(135deg, #1A1A1A 0%, #2F2F2F 100%);
      position: relative;
      display: flex;
      align-items: center;
      overflow: hidden;
    }
    .hero::before {
      content: '';
      position: absolute;
      inset: 0;
      background: radial-gradient(circle at 30% 40%, rgba(232,69,30,0.25) 0%, transparent 50%);
      z-index: 1;
    }
    .hero-bg-img {
      position: absolute;
      inset: 0;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      opacity: 0.4;
      z-index: 0;
    }
    .hero-content {
      position: relative;
      z-index: 2;
      max-width: 780px;
      color: white;
    }
    .hero h1 {
      font-size: clamp(48px, 7vw, 72px);
      font-weight: 900;
      line-height: 1.2;
      text-shadow: 0 4px 20px rgba(232,69,30,0.7);
      margin-bottom: 24px;
    }
    .hero .sub {
      font-size: 20px;
      opacity: 0.8;
      max-width: 600px;
      margin-bottom: 36px;
    }
    .hero-buttons {
      display: flex;
      gap: 20px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 16px 38px;
      border-radius: var(--radius-btn);
      font-size: 18px;
      box-shadow: 0 8px 22px rgba(232,69,30,0.5);
    }
    .btn-primary:hover {
      background: #c93615;
      transform: translateY(-2px);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid white;
      color: white;
      padding: 16px 38px;
      border-radius: var(--radius-btn);
      font-size: 18px;
    }
    .btn-outline:hover {
      background: rgba(255,255,255,0.1);
    }
    .scroll-indicator {
      position: absolute;
      bottom: 30px;
      left: 50%;
      transform: translateX(-50%);
      color: var(--gold);
      font-size: 28px;
      animation: pulse 1.8s infinite;
      z-index: 2;
    }
    @keyframes pulse { 0% { opacity: 0.6; transform: translateX(-50%) translateY(0); } 50% { opacity: 1; transform: translateX(-50%) translateY(6px); } 100% { opacity: 0.6; transform: translateX(-50%) translateY(0); } }
    /* 板块通用 */
    section {
      padding: 120px 0;
    }
    .section-title {
      font-size: 44px;
      font-weight: 800;
      margin-bottom: 20px;
      color: var(--dark);
    }
    .gold-underline {
      width: 64px;
      height: 4px;
      background: var(--gold);
      margin-bottom: 48px;
    }
    /* 优势不对称 */
    .advantages-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr;
      gap: 28px;
    }
    .adv-card {
      background: var(--white);
      border-radius: var(--radius-md);
      padding: 36px;
      box-shadow: var(--shadow-card);
      border: 1px solid var(--border-light);
      transition: all 0.3s;
    }
    .adv-card:hover {
      box-shadow: var(--shadow-card-hover);
    }
    .adv-large { grid-row: span 2; }
    .adv-icon { font-size: 48px; color: var(--primary); margin-bottom: 20px; }
    /* 服务卡片 */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      gap: 28px;
    }
    .service-card {
      background: var(--light-bg);
      border-radius: 20px;
      overflow: hidden;
      box-shadow: 0 4px 16px rgba(0,0,0,0.04);
      transition: 0.3s;
    }
    .service-card:hover {
      transform: translateY(-6px);
      box-shadow: 0 16px 32px rgba(0,0,0,0.1);
    }
    .service-img { height: 180px; background-size: cover; }
    .service-text { padding: 24px; }
    /* 数据 */
    .stats-band {
      background: var(--dark);
      padding: 100px 0;
    }
    .stats-grid {
      display: flex;
      justify-content: space-around;
      text-align: center;
      flex-wrap: wrap;
    }
    .stat-number {
      font-size: 68px;
      font-weight: 800;
      color: var(--gold);
    }
    /* 案例横滚 */
    .cases-scroll {
      display: flex;
      gap: 24px;
      overflow-x: auto;
      scroll-snap-type: x mandatory;
      padding-bottom: 16px;
    }
    .case-card {
      min-width: 320px;
      background: white;
      border-radius: var(--radius-sm);
      box-shadow: 0 2px 12px rgba(0,0,0,0.04);
      scroll-snap-align: start;
    }
    /* 解决方案 */
    .solution-row {
      display: flex;
      gap: 64px;
      align-items: center;
      margin-bottom: 100px;
    }
    .solution-img {
      flex:1; background-size: cover; border-radius: 24px; height: 340px;
    }
    /* FAQ */
    .faq-item {
      border:1px solid #ddd;
      border-radius: var(--radius-sm);
      margin-bottom: 16px;
      padding: 18px 24px;
      background: white;
    }
    .faq-question {
      font-weight: 700;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: 0.3s;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      margin-top: 12px;
    }
    /* CTA */
    .cta-dark {
      background: var(--dark);
      text-align: center;
      color: white;
    }
    .footer {
      background: #111;
      color: #ccc;
      padding: 60px 0;
    }
    @media (max-width: 992px) {
      .advantages-grid { grid-template-columns: 1fr 1fr; }
      .services-grid { grid-template-columns: repeat(2,1fr); }
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .menu-toggle { display: flex; }
      .hero h1 { font-size: 40px; }
      .advantages-grid { grid-template-columns: 1fr; }
      .solution-row { flex-direction: column; }
    }