/* roulang page: index */
/* ----- 设计变量与基础重置 ----- */
    :root {
      --glacier-blue: #00B4D8;
      --polar-black: #1A1A2E;
      --vivid-orange: #FF6B35;
      --ice-white: #F8FCFF;
      --light-ice: #E8F4F8;
      --white: #FFFFFF;
      --text-primary: #1A1A2E;
      --text-secondary: #2C3E50;
      --text-muted: rgba(26,26,46,0.65);
      --border-light: rgba(0,180,216,0.12);
      --shadow-card: 0 4px 20px rgba(26,26,46,0.06);
      --shadow-hover: 0 12px 30px rgba(0,180,216,0.12);
      --radius-card: 12px;
      --radius-btn: 8px;
      --transition: all 0.2s ease;
      --font-title: 'Montserrat', 'Noto Sans SC', sans-serif;
      --font-body: 'Inter', 'Noto Sans SC', sans-serif;
    }
    
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    
    body {
      font-family: var(--font-body);
      background-color: var(--ice-white);
      color: var(--text-primary);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }
    
    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-weight: 600;
      transition: var(--transition);
    }
    
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }
    
    /* 板块间距 */
    section {
      padding: 100px 0;
    }
    
    @media (max-width: 768px) {
      section {
        padding: 60px 0;
      }
      .container {
        padding: 0 16px;
      }
    }
    
    /* ----- 导航栏沉浸式固定 ----- */
    .navbar {
      position: fixed;
      top: 0;
      width: 100%;
      background: rgba(26, 26, 46, 0.8);
      backdrop-filter: blur(14px);
      -webkit-backdrop-filter: blur(14px);
      box-shadow: 0 4px 18px rgba(0,0,0,0.15);
      z-index: 1000;
      padding: 12px 0;
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-family: var(--font-title);
      font-weight: 700;
      font-size: 1.6rem;
      color: var(--white);
      letter-spacing: 0.5px;
    }
    .logo i {
      font-size: 2rem;
      color: var(--glacier-blue);
      text-shadow: 0 0 12px rgba(0,180,216,0.7);
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-links a {
      color: rgba(255,255,255,0.85);
      font-weight: 500;
      font-size: 1rem;
      position: relative;
      padding: 4px 0;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -2px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--glacier-blue);
      transition: width 0.25s ease;
    }
    .nav-links a:hover::after,
    .nav-links a.active::after {
      width: 100%;
    }
    .nav-cta {
      background: var(--vivid-orange);
      color: white !important;
      padding: 10px 24px !important;
      border-radius: var(--radius-btn);
      font-weight: 600;
      box-shadow: 0 8px 18px rgba(255,107,53,0.3);
    }
    .nav-cta:hover {
      background: #E55A2B;
    }
    .hamburger {
      display: none;
      font-size: 1.8rem;
      color: white;
      background: transparent;
    }
    
    @media (max-width: 768px) {
      .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 75%;
        max-width: 300px;
        height: 100vh;
        background: var(--polar-black);
        flex-direction: column;
        padding: 100px 30px 30px;
        gap: 28px;
        transition: right 0.3s ease;
        box-shadow: -8px 0 25px rgba(0,0,0,0.3);
        backdrop-filter: blur(10px);
      }
      .nav-links.open {
        right: 0;
      }
      .hamburger {
        display: block;
        z-index: 1001;
      }
      .nav-cta {
        width: 100%;
        text-align: center;
        margin-top: 10px;
      }
    }
    
    /* ----- 首屏 Hero 冰川渐变+速度感 ----- */
    #hero {
      background: linear-gradient(135deg, #1A1A2E 0%, #00B4D8 100%);
      background-size: cover;
      position: relative;
      min-height: 90vh;
      display: flex;
      align-items: center;
      padding-top: 80px;
      overflow: hidden;
    }
    #hero::before {
      content: '';
      position: absolute;
      inset: 0;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      opacity: 0.2;
      mix-blend-mode: overlay;
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 60px;
      position: relative;
      z-index: 2;
    }
    .hero-content {
      flex: 1;
    }
    .hero-title {
      font-family: var(--font-title);
      font-size: 3.4rem;
      font-weight: 800;
      color: white;
      line-height: 1.25;
      margin-bottom: 24px;
    }
    .hero-title span {
      color: var(--vivid-orange);
    }
    .hero-desc {
      font-size: 1.2rem;
      color: rgba(255,255,255,0.9);
      margin-bottom: 40px;
      max-width: 540px;
    }
    .hero-buttons {
      display: flex;
      flex-wrap: wrap;
      gap: 16px;
    }
    .btn-primary {
      background: var(--vivid-orange);
      color: white;
      padding: 14px 34px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      box-shadow: 0 8px 24px rgba(255,107,53,0.4);
    }
    .btn-primary:hover {
      background: #E55A2B;
      box-shadow: 0 0 24px rgba(255,107,53,0.6);
    }
    .btn-secondary {
      border: 2px solid var(--glacier-blue);
      color: white;
      padding: 14px 34px;
      border-radius: var(--radius-btn);
    }
    .btn-secondary:hover {
      background: rgba(0,180,216,0.2);
    }
    .hero-visual {
      flex: 1;
      display: flex;
      justify-content: center;
    }
    .hero-visual img {
      max-height: 380px;
      border-radius: 24px;
      box-shadow: 0 20px 40px rgba(0,0,0,0.4);
      border: 1px solid rgba(255,255,255,0.2);
    }
    @media (max-width: 992px) {
      .hero-grid {
        flex-direction: column;
        text-align: center;
        gap: 40px;
      }
      .hero-title {
        font-size: 2.8rem;
      }
    }
    
    /* 卡片通用 */
    .card {
      background: var(--white);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      border: 1px solid var(--border-light);
      transition: all 0.2s ease;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
      border-color: rgba(0,180,216,0.3);
    }
    
    /* 优势区域 非对称布局 */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 30px;
    }
    .feature-card {
      text-align: center;
      padding: 36px 22px;
    }
    .feature-icon {
      font-size: 2.3rem;
      color: var(--glacier-blue);
      margin-bottom: 16px;
    }
    
    /* 产品区交错 */
    .product-row {
      display: flex;
      flex-wrap: wrap;
      gap: 30px;
      align-items: center;
      margin-bottom: 70px;
    }
    .product-img {
      flex: 1 1 45%;
      border-radius: 16px;
      overflow: hidden;
    }
    .product-text {
      flex: 1 1 45%;
    }
    
    /* FAQ */
    .faq-item {
      border-bottom: 1px solid rgba(0,180,216,0.2);
      padding: 20px 0;
      cursor: pointer;
    }
    .faq-question {
      font-weight: 700;
      font-size: 1.2rem;
      display: flex;
      justify-content: space-between;
    }
    
    /* 页脚 */
    footer {
      background: var(--polar-black);
      color: rgba(255,255,255,0.7);
      padding: 60px 0 30px;
    }