/* roulang page: index */
:root {
      --deep-blue-black: #0B0F19;
      --tech-blue-start: #1E3A5F;
      --tech-blue-end: #2A5C8A;
      --accent-blue: #3B82F6;
      --warm-gold: #D4A843;
      --neutral-light: #F1F5F9;
      --text-muted: #94A3B8;
      --success-green: #10B981;
      --glass-bg: rgba(255, 255, 255, 0.03);
      --glass-border: rgba(255, 255, 255, 0.06);
      --card-solid-bg: #1A2332;
      --glow-gold: 0 0 24px rgba(212, 168, 67, 0.5);
      --glow-blue: 0 12px 40px rgba(59, 130, 246, 0.15);
      --body-text: #CBD5E1;
      --radius-lg: 16px;
      --radius-md: 12px;
      --radius-sm: 8px;
      --font-sans: 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', system-ui;
      --font-inter: 'Inter', sans-serif;
    }

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

    body {
      font-family: var(--font-sans);
      background: radial-gradient(circle at 30% 10%, #111827, #0B0F19 70%);
      background-color: #0B0F19;
      color: #fff;
      line-height: 1.75;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

    ::selection {
      background-color: var(--warm-gold);
      color: #0B0F19;
    }

    h1, h2, h3 {
      font-weight: 700;
      letter-spacing: -0.02em;
      line-height: 1.3;
    }

    h1 { font-size: 42px; }
    h2 { font-size: 32px; }
    h3 { font-size: 20px; font-weight: 600; }
    .text-body { color: var(--body-text); font-weight: 400; }
    .text-muted { color: var(--text-muted); font-size: 14px; }
    .font-inter { font-family: var(--font-inter); }

    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding-left: 24px;
      padding-right: 24px;
    }

    /* 导航 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 50;
      background: rgba(11, 15, 25, 0.7);
      backdrop-filter: blur(24px);
      -webkit-backdrop-filter: blur(24px);
      border-bottom: 1px solid rgba(255,255,255,0.08);
      transition: background 0.3s ease, box-shadow 0.3s ease;
    }
    .navbar.scrolled {
      background: rgba(11, 15, 25, 0.92);
      box-shadow: 0 8px 30px rgba(0,0,0,0.6);
    }
    .logo-text {
      font-family: var(--font-sans);
      font-weight: 700;
      font-size: 28px;
      letter-spacing: 2px;
      background: linear-gradient(to right, #fff, #94A3B8);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    .nav-link {
      color: #CBD5E1;
      font-weight: 500;
      transition: color 0.2s;
      position: relative;
    }
    .nav-link:hover, .nav-link.active {
      color: #fff;
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--warm-gold);
      transition: width 0.3s ease;
    }
    .nav-link:hover::after, .nav-link.active::after {
      width: 100%;
    }

    /* 按钮 */
    .btn-primary {
      background: linear-gradient(135deg, #3B82F6, #2563EB);
      border-radius: var(--radius-sm);
      color: white;
      font-weight: 600;
      padding: 12px 28px;
      box-shadow: 0 4px 14px rgba(37, 99, 235, 0.4);
      transition: all 0.3s ease;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      border: none;
      cursor: pointer;
    }
    .btn-primary:hover {
      box-shadow: 0 8px 22px rgba(59,130,246,0.6);
      transform: translateY(-1px);
    }
    .btn-glow {
      background: rgba(212,168,67,0.08);
      border: 1px solid var(--warm-gold);
      color: var(--warm-gold);
      border-radius: var(--radius-sm);
      padding: 12px 32px;
      font-weight: 600;
      box-shadow: 0 0 18px rgba(212,168,67,0.35);
      transition: all 0.3s ease;
      backdrop-filter: blur(10px);
    }
    .btn-glow:hover {
      background: rgba(212,168,67,0.18);
      box-shadow: 0 0 35px rgba(212,168,67,0.65);
      transform: scale(1.02);
    }
    .btn-outline-light {
      border: 1px solid rgba(255,255,255,0.2);
      color: #fff;
      background: transparent;
      border-radius: var(--radius-sm);
      padding: 12px 24px;
      transition: all 0.3s;
    }
    .btn-outline-light:hover {
      border-color: rgba(255,255,255,0.6);
      background: rgba(255,255,255,0.05);
    }

    /* 玻璃卡片 */
    .glass-card {
      background: var(--glass-bg);
      border: 1px solid var(--glass-border);
      border-radius: var(--radius-lg);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      box-shadow: 0 4px 24px rgba(0,0,0,0.3);
    }
    .solid-card {
      background: var(--card-solid-bg);
      border-radius: var(--radius-md);
    }

    /* 动画 */
    @keyframes float {
      0% { transform: translateY(0); }
      50% { transform: translateY(-8px); }
      100% { transform: translateY(0); }
    }
    .float-animation {
      animation: float 6s ease-in-out infinite;
    }
    .fade-up {
      opacity: 0;
      transform: translateY(30px);
      transition: opacity 0.6s ease, transform 0.6s ease;
    }
    .fade-up.visible {
      opacity: 1;
      transform: translateY(0);
    }

    /* 手风琴 */
    .faq-item {
      border-bottom: 1px solid rgba(255,255,255,0.08);
      padding: 20px 0;
      cursor: pointer;
    }
    .faq-question {
      display: flex;
      align-items: center;
      justify-content: space-between;
      font-weight: 600;
      font-size: 18px;
      color: #F1F5F9;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease, padding 0.35s ease;
      color: #CBD5E1;
      font-size: 15px;
      line-height: 1.7;
    }
    .faq-item.open .faq-answer {
      max-height: 300px;
      padding-top: 16px;
      border-left: 3px solid var(--accent-blue);
      padding-left: 20px;
    }
    .faq-icon {
      transition: transform 0.3s ease;
      color: var(--warm-gold);
    }
    .faq-item.open .faq-icon {
      transform: rotate(45deg);
    }

    /* 案例瀑布 */
    .masonry-grid {
      column-count: 2;
      column-gap: 24px;
    }
    .masonry-item {
      break-inside: avoid;
      margin-bottom: 24px;
      background: #1A2332;
      border-radius: var(--radius-lg);
      overflow: hidden;
      transition: transform 0.3s ease, box-shadow 0.3s ease;
    }
    .masonry-item:hover {
      transform: translateY(-6px);
      box-shadow: 0 16px 36px rgba(59,130,246,0.2);
    }
    @media (max-width: 768px) {
      .masonry-grid {
        column-count: 1;
      }
    }

    /* 响应式 */
    @media (max-width: 1024px) {
      h1 { font-size: 36px; }
      h2 { font-size: 28px; }
    }
    @media (max-width: 640px) {
      h1 { font-size: 28px; }
      h2 { font-size: 24px; }
      .container { padding: 0 20px; }
    }

    .mobile-menu {
      transform: translateX(100%);
      transition: transform 0.4s ease;
    }
    .mobile-menu.open {
      transform: translateX(0);
    }