/* roulang page: index */
/* ----- 设计变量 & 全局重置 ----- */
    :root {
      --primary-deep: #0A1929;
      --primary-bg: #030B14;
      --accent-orange: #FF6B35;
      --accent-green: #00E676;
      --text-main: #FFFFFF;
      --text-secondary: #B0C4DE;
      --text-muted: #8899AA;
      --card-bg: rgba(18, 30, 45, 0.6);
      --card-border: rgba(255,255,255,0.08);
      --card-hover-border: rgba(255,107,53,0.35);
      --glass-blur: blur(16px);
      --radius-card: 20px;
      --radius-btn: 50px;
      --radius-input: 12px;
      --shadow-card: 0 8px 32px rgba(0,0,0,0.4);
      --shadow-hover: 0 12px 40px rgba(0,0,0,0.6);
      --transition: 0.25s ease;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Inter", sans-serif;
    }

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

    body {
      background: var(--primary-bg);
      color: var(--text-main);
      font-family: var(--font-sans);
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
      scroll-behavior: smooth;
      background-image: radial-gradient(circle at 20% 10%, #0B1D3A 0%, #030B14 90%);
    }

    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 32px;
    }

    a {
      text-decoration: none;
      color: inherit;
      transition: color var(--transition);
    }

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

    button, .btn {
      cursor: pointer;
      font-family: var(--font-sans);
      transition: all var(--transition);
      border: none;
      outline: none;
    }

    /* 通用板块间距 */
    section {
      padding: 100px 0;
      position: relative;
    }

    /* 标题系统 */
    h1 {
      font-size: 3.2rem;
      font-weight: 700;
      letter-spacing: -0.02em;
      line-height: 1.2;
    }
    h2 {
      font-size: 2.3rem;
      font-weight: 600;
      letter-spacing: -0.01em;
      margin-bottom: 16px;
    }
    h3 {
      font-size: 1.5rem;
      font-weight: 500;
    }
    .section-subtitle {
      color: var(--text-secondary);
      font-size: 1.15rem;
      margin-bottom: 48px;
      max-width: 600px;
    }

    /* 按钮组件 */
    .btn-primary {
      background: var(--accent-orange);
      color: white;
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 1rem;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      box-shadow: 0 4px 15px rgba(255,107,53,0.3);
    }
    .btn-primary:hover {
      background: #ff7a50;
      box-shadow: 0 0 24px rgba(255,107,53,0.6);
      transform: scale(1.02);
    }
    .btn-outline {
      background: transparent;
      border: 1px solid rgba(255,255,255,0.25);
      color: white;
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-weight: 500;
      backdrop-filter: blur(8px);
    }
    .btn-outline:hover {
      background: rgba(255,255,255,0.08);
      border-color: rgba(255,255,255,0.5);
      transform: translateY(-1px);
    }

    /* 导航 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      background: transparent;
      transition: background 0.3s ease, backdrop-filter 0.3s ease;
      padding: 16px 0;
    }
    .site-header.scrolled {
      background: rgba(10, 25, 41, 0.88);
      backdrop-filter: blur(20px);
      box-shadow: 0 4px 20px rgba(0,0,0,0.3);
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 700;
      font-size: 1.5rem;
      color: white;
    }
    .logo-icon {
      font-size: 2rem;
      color: var(--accent-orange);
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 36px;
    }
    .nav-links a {
      color: var(--text-secondary);
      font-weight: 500;
      font-size: 0.95rem;
      position: relative;
    }
    .nav-links a:hover, .nav-links a.active {
      color: white;
    }
    .nav-cta {
      margin-left: 16px;
    }
    .hamburger {
      display: none;
      background: none;
      border: none;
      color: white;
      font-size: 1.8rem;
      cursor: pointer;
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: rgba(8, 20, 33, 0.96);
      backdrop-filter: blur(24px);
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 40px;
      z-index: 999;
      font-size: 1.5rem;
    }
    .mobile-menu a {
      color: white;
      font-weight: 600;
    }
    .mobile-menu .close-menu {
      position: absolute;
      top: 30px;
      right: 30px;
      font-size: 2rem;
      background: none;
      border: none;
      color: white;
    }

    /* 卡片通用 */
    .glass-card {
      background: var(--card-bg);
      backdrop-filter: var(--glass-blur);
      border: 1px solid var(--card-border);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      padding: 32px;
      transition: all var(--transition);
    }
    .glass-card:hover {
      border-color: var(--card-hover-border);
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }

    /* 响应式 */
    @media (max-width: 1024px) {
      .container { padding: 0 24px; }
      h1 { font-size: 2.6rem; }
      h2 { font-size: 2rem; }
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: block; }
      section { padding: 70px 0; }
      h1 { font-size: 2.2rem; }
      .container { padding: 0 20px; }
      .header-inner .btn-primary { display: none; }
    }