/* roulang page: index */
:root {
      --bg-deep: #0A0E27;
      --bg-card: rgba(15, 21, 53, 0.65);
      --accent-orange: #FF6B35;
      --accent-orange-light: #FF8C42;
      --ice-blue: #00D2FF;
      --text-primary: #FFFFFF;
      --text-secondary: #B0C4DE;
      --border-glow: rgba(0, 210, 255, 0.18);
      --border-subtle: rgba(0, 210, 255, 0.08);
      --shadow-card: 0 8px 32px rgba(0, 0, 0, 0.45), inset 0 1px 0 rgba(255, 255, 255, 0.05);
      --shadow-button: 0 4px 18px rgba(255, 107, 53, 0.5);
      --blur-glass: blur(22px);
      --radius-card: 20px;
      --radius-btn: 16px;
      --font-sans: 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
      --font-number: 'Inter', 'Noto Sans SC', sans-serif;
      --spacing-container: clamp(16px, 5vw, 40px);
    }

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

    body {
      background-color: var(--bg-deep);
      color: var(--text-primary);
      font-family: var(--font-sans);
      line-height: 1.7;
      font-weight: 400;
      -webkit-font-smoothing: antialiased;
      transition: background-color 0.2s;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s, border-color 0.2s;
    }

    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding-left: var(--spacing-container);
      padding-right: var(--spacing-container);
      width: 100%;
    }

    /* 导航系统 - 沉浸式毛玻璃吸附 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      background: transparent;
      transition: background 0.3s, backdrop-filter 0.3s, box-shadow 0.3s;
      height: 70px;
      display: flex;
      align-items: center;
    }

    .site-header.scrolled {
      background: rgba(10, 14, 39, 0.88);
      backdrop-filter: var(--blur-glass);
      box-shadow: 0 4px 26px rgba(0, 0, 0, 0.5);
      border-bottom: 1px solid rgba(0, 210, 255, 0.15);
    }

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

    .logo {
      font-weight: 800;
      font-size: 1.9rem;
      letter-spacing: -0.02em;
      display: flex;
      align-items: center;
      gap: 5px;
      color: white;
      transition: opacity 0.2s;
      white-space: nowrap;
    }
    .logo .yi {
      color: var(--accent-orange);
      text-shadow: 0 0 12px rgba(255, 107, 53, 0.7);
    }
    .logo-arc {
      display: inline-block;
      width: 22px;
      height: 22px;
      border-left: 3px solid var(--ice-blue);
      border-bottom: 3px solid var(--ice-blue);
      border-radius: 50%;
      margin-left: 6px;
      transform: rotate(-25deg);
      filter: drop-shadow(0 0 6px #00D2FF);
      opacity: 0.9;
    }

    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
    }

    .nav-link {
      font-weight: 600;
      font-size: 1rem;
      color: #E6EDF5;
      padding: 6px 2px;
      border-bottom: 2px solid transparent;
      transition: all 0.2s;
      letter-spacing: 0.3px;
    }

    .nav-link:hover {
      color: white;
      border-bottom-color: var(--ice-blue);
      text-shadow: 0 0 12px rgba(0,210,255,0.55);
    }

    .btn-primary {
      background: linear-gradient(135deg, #FF6B35 0%, #FF8C42 100%);
      color: white;
      font-weight: 700;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      border: none;
      cursor: pointer;
      box-shadow: var(--shadow-button);
      transition: all 0.3s ease;
      letter-spacing: 0.5px;
      white-space: nowrap;
      font-size: 0.95rem;
      display: inline-block;
    }

    .btn-primary:hover {
      box-shadow: 0 6px 28px rgba(255, 107, 53, 0.8);
      transform: scale(1.03);
    }

    .btn-ghost {
      background: transparent;
      border: 2px solid var(--ice-blue);
      color: var(--ice-blue);
      font-weight: 600;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      transition: all 0.3s;
      white-space: nowrap;
    }
    .btn-ghost:hover {
      background: rgba(0,210,255,0.1);
      color: white;
      border-color: white;
      box-shadow: 0 0 22px rgba(0,210,255,0.4);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: transparent;
      border: none;
    }
    .hamburger span {
      width: 26px;
      height: 3px;
      background: white;
      border-radius: 3px;
      transition: 0.3s;
    }

    @media (max-width: 1024px) {
      .nav-menu {
        gap: 20px;
      }
    }
    @media (max-width: 768px) {
      .hamburger {
        display: flex;
      }
      .nav-menu {
        position: fixed;
        top: 70px;
        left: 0;
        width: 100%;
        flex-direction: column;
        background: rgba(8, 12, 32, 0.96);
        backdrop-filter: blur(28px);
        padding: 30px 24px;
        gap: 24px;
        transform: translateY(-150%);
        transition: transform 0.35s ease;
        border-bottom: 1px solid var(--border-glow);
        align-items: flex-start;
      }
      .nav-menu.active {
        transform: translateY(0);
      }
      .site-header.scrolled .nav-menu {
        background: rgba(10, 14, 39, 0.96);
      }
    }

    /* HERO */
    .hero {
      padding: 140px 0 100px;
      min-height: 90vh;
      display: flex;
      align-items: center;
      background: radial-gradient(circle at 20% 30%, rgba(0,210,255,0.08) 0%, transparent 55%), 
                  radial-gradient(circle at 80% 70%, rgba(255,107,53,0.12) 0%, transparent 60%);
      position: relative;
      overflow: hidden;
    }
    .hero-bg {
      position: absolute;
      right: -20px;
      top: 70px;
      width: 48%;
      height: 100%;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      mask-image: linear-gradient(to left, rgba(0,0,0,0.7), transparent 90%);
      opacity: 0.35;
      z-index: 0;
    }
    .hero-content {
      position: relative;
      z-index: 2;
      max-width: 600px;
    }
    .hero h1 {
      font-size: clamp(2.8rem, 6vw, 4rem);
      font-weight: 800;
      background: linear-gradient(to right, var(--ice-blue), #ffffff);
      -webkit-background-clip: text;
      background-clip: text;
      color: transparent;
      line-height: 1.15;
      margin-bottom: 24px;
      text-shadow: 0 0 45px rgba(0,210,255,0.35);
      letter-spacing: -0.02em;
    }
    .hero-sub {
      font-size: 1.15rem;
      color: #B0C4DE;
      margin-bottom: 36px;
      max-width: 480px;
    }
    .btn-group {
      display: flex;
      gap: 18px;
      flex-wrap: wrap;
    }

    section {
      padding: 100px 0;
    }

    h2 {
      font-size: 2.2rem;
      font-weight: 700;
      margin-bottom: 16px;
      position: relative;
      display: inline-block;
    }
    h2::after {
      content: '';
      position: absolute;
      bottom: -8px;
      left: 0;
      width: 60px;
      height: 3px;
      background: var(--ice-blue);
      box-shadow: 0 0 14px var(--ice-blue);
      border-radius: 3px;
    }
    .section-sub {
      color: #B0C4DE;
      margin-bottom: 48px;
    }

    .card-glass {
      background: var(--bg-card);
      backdrop-filter: var(--blur-glass);
      border: 1px solid rgba(0, 210, 255, 0.2);
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--shadow-card);
      transition: all 0.3s ease;
    }
    .card-glass:hover {
      border-color: rgba(0,210,255,0.45);
      box-shadow: 0 12px 38px rgba(0,0,0,0.6), 0 0 26px rgba(0,210,255,0.35);
      transform: translateY(-6px);
    }

    .grid-3 { display: grid; grid-template-columns: repeat(3,1fr); gap: 28px; }
    .grid-2-1-2 { display: grid; grid-template-columns: 2fr 0.8fr 2fr; gap: 24px; align-items: center; }
    .stat-grid { display: grid; grid-template-columns: repeat(4,1fr); gap: 24px; }

    @media (max-width: 1024px) {
      .grid-3 { grid-template-columns: repeat(2,1fr); }
      .grid-2-1-2 { grid-template-columns: 1fr 0.5fr 1fr; }
      .stat-grid { grid-template-columns: repeat(2,1fr); }
    }
    @media (max-width: 768px) {
      section { padding: 70px 0; }
      .grid-3, .grid-2-1-2, .stat-grid { grid-template-columns: 1fr; }
      .btn-group { flex-direction: column; align-items: center; }
      .hero { padding: 120px 0 70px; }
      .hero-bg { width: 100%; right: 0; opacity: 0.2; }
    }

    .testimonial-cards { display: grid; grid-template-columns: repeat(3,1fr); gap: 28px; }
    @media (max-width: 768px) { .testimonial-cards { grid-template-columns: 1fr; } }

    .faq-container { max-width: 800px; margin: 0 auto; }
    .accordion { border-bottom: 1px solid var(--border-subtle); }
    .accordion-header { padding: 20px 0; font-weight: 700; display: flex; justify-content: space-between; cursor: pointer; }
    .accordion-content { max-height: 0; overflow: hidden; transition: max-height 0.4s ease; color: #B0C4DE; }

    .cta-final {
      background: #080C20;
      text-align: center;
      padding: 100px 20px;
    }
    footer {
      background: #060918;
      padding: 60px 0 30px;
      color: #B0C4DE;
    }