/* roulang page: index */
:root {
      --primary-bg: #0B0E14;
      --accent-gold: #D4AF37;
      --warm-paper: #F5F0E8;
      --accent-red: #C44536;
      --text-dark: #1A1A1A;
      --text-muted: #5C5C5C;
      --border-light: #E0DBD2;
      --shadow-card: 0 2px 12px rgba(0,0,0,0.04);
      --shadow-hover: 0 8px 24px rgba(0,0,0,0.08);
      --radius-sm: 8px;
      --radius-lg: 12px;
      --font-sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --transition-smooth: 0.3s ease;
    }

    * {
      box-sizing: border-box;
    }

    body {
      font-family: var(--font-sans);
      background-color: var(--warm-paper);
      color: var(--text-dark);
      line-height: 1.75;
      margin: 0;
      padding: 0;
      -webkit-font-smoothing: antialiased;
      display: flex;
      min-height: 100vh;
    }

    /* 左侧导航 App Shell */
    .app-nav {
      position: fixed;
      left: 0;
      top: 0;
      width: 72px;
      height: 100vh;
      background-color: var(--primary-bg);
      display: flex;
      flex-direction: column;
      align-items: center;
      padding: 2rem 0;
      z-index: 50;
      box-shadow: 2px 0 12px rgba(0,0,0,0.08);
    }

    .nav-logo {
      font-size: 1rem;
      font-weight: 700;
      color: var(--accent-gold);
      writing-mode: vertical-rl;
      letter-spacing: 0.2em;
      margin-bottom: 2.5rem;
      text-orientation: upright;
      line-height: 1.2;
    }

    .nav-menu {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 1.8rem;
      flex: 1;
    }

    .nav-item {
      display: flex;
      flex-direction: column;
      align-items: center;
      color: #8A8A8A;
      font-size: 12px;
      text-decoration: none;
      transition: color var(--transition-smooth), border var(--transition-smooth);
      position: relative;
      padding: 0.25rem 0;
      writing-mode: vertical-rl;
      text-orientation: upright;
      letter-spacing: 0.05em;
    }

    .nav-item i {
      font-size: 1.2rem;
      margin-bottom: 0.2rem;
      writing-mode: horizontal-tb;
    }

    .nav-item:hover,
    .nav-item.active {
      color: var(--accent-gold);
    }

    .nav-item::before {
      content: '';
      position: absolute;
      left: -8px;
      top: 0;
      height: 100%;
      width: 2px;
      background-color: var(--accent-gold);
      transform: scaleY(0);
      transition: transform 0.2s ease;
    }

    .nav-item:hover::before,
    .nav-item.active::before {
      transform: scaleY(1);
    }

    /* 主内容区域 */
    .main-content {
      margin-left: 72px;
      width: calc(100% - 72px);
      max-width: 1200px;
      margin-right: auto;
      padding: 0 2rem;
    }

    /* 移动端顶部导航 */
    .mobile-header {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 64px;
      background-color: var(--primary-bg);
      align-items: center;
      justify-content: space-between;
      padding: 0 1.5rem;
      z-index: 55;
    }

    .hamburger {
      color: var(--warm-paper);
      font-size: 1.5rem;
      background: none;
      border: none;
      cursor: pointer;
    }

    .mobile-logo {
      font-weight: 700;
      color: var(--accent-gold);
      letter-spacing: 0.1em;
    }

    .drawer {
      position: fixed;
      top: 0;
      left: 0;
      width: 280px;
      height: 100vh;
      background-color: var(--primary-bg);
      z-index: 60;
      transform: translateX(-100%);
      transition: transform 0.3s ease;
      padding: 2rem 1.5rem;
      display: flex;
      flex-direction: column;
    }

    .drawer.open {
      transform: translateX(0);
    }

    .drawer a {
      color: #ccc;
      font-size: 1.1rem;
      padding: 0.8rem 0;
      text-decoration: none;
      border-bottom: 1px solid rgba(255,255,255,0.08);
      transition: color 0.2s;
    }

    .drawer a:hover {
      color: var(--accent-gold);
    }

    /* 基础重置 */
    a, button, input {
      font-family: inherit;
    }

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

    h1, h2, h3, p {
      margin: 0;
    }

    .container-custom {
      width: 100%;
      max-width: 1100px;
      margin: 0 auto;
    }

    /* 按钮 */
    .btn-primary {
      background-color: var(--accent-gold);
      color: #0B0E14;
      font-weight: 600;
      border-radius: 6px;
      padding: 14px 36px;
      text-decoration: none;
      display: inline-block;
      transition: all 0.25s;
      border: none;
      cursor: pointer;
      letter-spacing: 0.02em;
    }

    .btn-primary:hover {
      background-color: #B8962E;
      transform: translateY(-2px);
      box-shadow: 0 10px 20px rgba(0,0,0,0.1);
    }

    .btn-secondary {
      background: transparent;
      border: 1px solid var(--accent-gold);
      color: var(--accent-gold);
      font-weight: 600;
      border-radius: 6px;
      padding: 14px 36px;
      text-decoration: none;
      display: inline-block;
      transition: all 0.25s;
    }

    .btn-secondary:hover {
      background-color: rgba(212,175,55,0.1);
    }

    .card {
      background: #fff;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-lg);
      padding: 32px;
      box-shadow: var(--shadow-card);
      transition: all var(--transition-smooth);
    }

    .card:hover {
      box-shadow: var(--shadow-hover);
      border-color: var(--accent-gold);
      transform: translateY(-4px);
    }

    .section-spacing {
      margin: 120px 0;
    }

    .fade-up {
      opacity: 0;
      transform: translateY(20px);
      transition: opacity 0.6s ease, transform 0.6s ease;
    }

    .fade-up.visible {
      opacity: 1;
      transform: translateY(0);
    }

    @media (max-width: 768px) {
      .app-nav {
        display: none;
      }
      .mobile-header {
        display: flex;
      }
      .main-content {
        margin-left: 0;
        width: 100%;
        padding: 80px 1.5rem 0;
      }
      .section-spacing {
        margin: 64px 0;
      }
      .btn-primary, .btn-secondary {
        display: block;
        width: 100%;
        text-align: center;
        padding: 16px 0;
      }
      h1 {
        font-size: 2.5rem !important;
      }
      h2 {
        font-size: 2rem !important;
      }
    }