/* roulang page: index */
:root {
      --milan-red: #C41E3A;
      --milan-red-deep: #A01830;
      --gray-black: #1C1C1E;
      --warm-white: #F9F6F0;
      --text-primary: #1C1C1E;
      --text-secondary: #5A5A5E;
      --text-light: #AAAAAA;
      --border-light: #E8E5DF;
      --shadow-sm: 0 4px 20px rgba(0,0,0,0.04);
      --shadow-md: 0 12px 32px rgba(0,0,0,0.08);
      --shadow-hover: 0 18px 36px rgba(0,0,0,0.1);
      --radius-card: 16px;
      --radius-btn: 40px;
      --transition-smooth: 0.3s cubic-bezier(0.25, 0.8, 0.25, 1.2);
      --font-stack: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      --container-max: 1280px;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }
    body {
      font-family: var(--font-stack);
      background-color: var(--warm-white);
      color: var(--text-primary);
      line-height: 1.75;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s;
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
    }
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }
    /* 导航 */
    .nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid rgba(0,0,0,0.04);
      transition: background 0.3s, box-shadow 0.3s;
      height: 72px;
    }
    .nav.scrolled {
      background: rgba(255,255,255,0.98);
      box-shadow: 0 4px 24px rgba(0,0,0,0.06);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }
    .logo {
      font-size: 1.8rem;
      font-weight: 800;
      color: var(--milan-red);
      letter-spacing: -0.02em;
      white-space: nowrap;
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
      list-style: none;
    }
    .nav-links a {
      font-weight: 500;
      color: var(--text-primary);
      font-size: 0.95rem;
      position: relative;
      padding: 4px 0;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -2px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--milan-red);
      transition: width 0.25s;
    }
    .nav-links a:hover::after,
    .nav-links a.active::after {
      width: 100%;
    }
    .btn-primary {
      background: var(--milan-red);
      color: white;
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      border: none;
      transition: background 0.25s, transform 0.2s;
      display: inline-block;
      letter-spacing: 0.5px;
      box-shadow: 0 4px 12px rgba(196,30,58,0.2);
    }
    .btn-primary:hover {
      background: var(--milan-red-deep);
      transform: scale(1.03);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--milan-red);
      color: var(--milan-red);
      padding: 12px 34px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: all 0.25s;
    }
    .btn-outline:hover {
      background: var(--milan-red);
      color: white;
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: none;
      border: none;
      cursor: pointer;
    }
    .hamburger span {
      width: 26px;
      height: 2px;
      background: var(--gray-black);
      transition: 0.2s;
    }
    /* Hero */
    .hero {
      min-height: 100vh;
      display: flex;
      align-items: center;
      background: linear-gradient(135deg, #1C1C1E 0%, #2A2A2D 100%);
      position: relative;
      overflow: hidden;
      padding-top: 72px;
    }
    .hero-bg-particles {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      opacity: 0.35;
      mix-blend-mode: overlay;
    }
    .hero-content {
      position: relative;
      z-index: 2;
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
      gap: 40px;
    }
    .hero-text {
      flex: 1;
      color: white;
    }
    .hero-text h1 {
      font-size: clamp(2.8rem, 6vw, 4rem);
      font-weight: 900;
      line-height: 1.2;
      letter-spacing: -0.02em;
      margin-bottom: 24px;
      animation: fadeInUp 0.8s ease;
    }
    .hero-text .subtitle {
      font-size: 1.25rem;
      color: rgba(255,255,255,0.8);
      margin-bottom: 40px;
      max-width: 540px;
    }
    .hero-buttons {
      display: flex;
      gap: 20px;
      flex-wrap: wrap;
    }
    .hero-visual {
      flex: 1;
      display: flex;
      justify-content: center;
      align-items: center;
    }
    .hero-visual img {
      max-height: 420px;
      filter: drop-shadow(0 20px 30px rgba(0,0,0,0.5));
      animation: float 6s ease-in-out infinite;
    }
    @keyframes fadeInUp {
      from { opacity: 0; transform: translateY(30px); }
      to { opacity: 1; transform: translateY(0); }
    }
    @keyframes float {
      0% { transform: translateY(0); }
      50% { transform: translateY(-12px); }
      100% { transform: translateY(0); }
    }
    /* 通用板块 */
    section {
      padding: 120px 0;
    }
    .section-title {
      text-align: center;
      margin-bottom: 64px;
    }
    .section-title h2 {
      font-size: 2.5rem;
      font-weight: 700;
      letter-spacing: -0.02em;
      color: var(--gray-black);
    }
    .section-title p {
      color: var(--text-secondary);
      margin-top: 16px;
      font-size: 1.1rem;
    }
    /* 优势卡片 */
    .advantages-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px;
    }
    .advantage-card {
      background: white;
      padding: 40px 32px;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      transition: var(--transition-smooth);
      border-bottom: 3px solid transparent;
    }
    .advantage-card:hover {
      transform: translateY(-8px);
      box-shadow: var(--shadow-hover);
      border-bottom-color: var(--milan-red);
    }
    .advantage-icon {
      font-size: 2.2rem;
      color: var(--milan-red);
      margin-bottom: 20px;
    }
    .advantage-card h3 {
      font-size: 1.5rem;
      margin-bottom: 12px;
    }
    /* 产品左右交替 */
    .product-row {
      display: flex;
      align-items: center;
      gap: 60px;
      margin-bottom: 100px;
    }
    .product-row.reverse {
      flex-direction: row-reverse;
    }
    .product-img {
      flex: 1;
      border-radius: 24px;
      overflow: hidden;
    }
    .product-img img {
      width: 100%;
      height: auto;
      object-fit: cover;
    }
    .product-info {
      flex: 1;
    }
    .product-info h3 {
      font-size: 2rem;
      font-weight: 700;
      margin-bottom: 16px;
    }
    .tag {
      display: inline-block;
      background: rgba(196,30,58,0.08);
      color: var(--milan-red);
      padding: 4px 14px;
      border-radius: 20px;
      font-size: 0.8rem;
      font-weight: 600;
      margin-bottom: 16px;
    }
    /* 场景卡片 */
    .scenarios-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px;
    }
    .scenario-card {
      background: white;
      padding: 36px 28px;
      border-radius: var(--radius-card);
      text-align: center;
      box-shadow: var(--shadow-sm);
      transition: var(--transition-smooth);
    }
    .scenario-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-md);
    }
    /* 案例网格 */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 32px;
    }
    .case-card {
      background: white;
      border-radius: var(--radius-card);
      padding: 32px;
      display: flex;
      gap: 24px;
      align-items: center;
      box-shadow: var(--shadow-sm);
    }
    .case-logo {
      width: 70px;
      height: 70px;
      background: #f0f0f0;
      border-radius: 16px;
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .case-data {
      font-weight: 700;
      color: var(--milan-red);
      font-size: 1.8rem;
    }
    /* FAQ */
    .faq-item {
      background: white;
      border-radius: 12px;
      margin-bottom: 16px;
      box-shadow: 0 2px 8px rgba(0,0,0,0.02);
    }
    .faq-question {
      padding: 20px 28px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      background: var(--warm-white);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      background: #fff;
      border-left: 4px solid var(--milan-red);
      padding: 0 28px;
    }
    .faq-answer.open {
      max-height: 200px;
      padding: 20px 28px;
    }
    /* CTA 横幅 */
    .cta-band {
      background: var(--milan-red);
      color: white;
      text-align: center;
      padding: 80px 24px;
    }
    /* 页脚 */
    .footer {
      background: var(--gray-black);
      color: #AAA;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    @media (max-width: 1024px) {
      .advantages-grid, .scenarios-grid { grid-template-columns: repeat(2,1fr); }
      .cases-grid { grid-template-columns: 1fr; }
      .product-row { flex-direction: column; gap: 32px; }
      .product-row.reverse { flex-direction: column; }
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .hero-content { flex-direction: column; text-align: center; }
      .advantages-grid, .scenarios-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr; }
      section { padding: 80px 0; }
    }
    .mobile-menu {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: white;
      z-index: 999;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 32px;
      font-size: 1.5rem;
      transform: translateX(100%);
      transition: 0.3s;
    }
    .mobile-menu.active {
      transform: translateX(0);
    }