/* roulang page: index */
:root {
      --gold: #C8963E;
      --gold-dark: #A67B2E;
      --ink: #2C2E33;
      --paper: #FBF7F2;
      --vermillion: #B83A2A;
      --vermillion-dark: #8C2A1D;
      --success-green: #2D6A4F;
      --border-light: #E8E2D8;
      --text-secondary: #5A5D63;
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 6px;
      --shadow-sm: 0 2px 12px rgba(44,46,51,0.06);
      --shadow-md: 0 6px 20px rgba(44,46,51,0.10);
      --font-serif: 'Noto Serif SC', 'Source Han Serif SC', serif;
      --font-sans: 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
    }
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--paper);
      color: var(--ink);
      line-height: 1.75;
      font-size: 16px;
      display: flex;
      min-height: 100vh;
      overflow-x: hidden;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s ease, border-color 0.2s ease;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    button, input, textarea {
      font-family: inherit;
      outline: none;
    }
    /* 左侧导航桌面 */
    #main-nav {
      width: 220px;
      min-width: 220px;
      background-color: var(--ink);
      color: white;
      height: 100vh;
      position: sticky;
      top: 0;
      left: 0;
      display: flex;
      flex-direction: column;
      padding: 2rem 1.25rem;
      z-index: 50;
      box-shadow: 2px 0 12px rgba(0,0,0,0.04);
    }
    .nav-brand {
      font-family: var(--font-serif);
      font-size: 1.6rem;
      font-weight: 700;
      color: white;
      margin-bottom: 3rem;
      display: flex;
      align-items: center;
      gap: 0.5rem;
      letter-spacing: 0.5px;
    }
    .nav-brand i {
      color: var(--gold);
      font-size: 1.8rem;
    }
    .nav-links {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 0.75rem;
      flex: 1;
    }
    .nav-links li a {
      display: block;
      padding: 0.7rem 1rem;
      border-radius: 6px;
      color: rgba(255,255,255,0.8);
      font-weight: 500;
      font-size: 1rem;
      transition: all 0.2s;
      border-left: 3px solid transparent;
    }
    .nav-links li a:hover, .nav-links li a.active {
      color: var(--gold);
      background-color: rgba(255,255,255,0.05);
      border-left-color: var(--gold);
    }
    .nav-footer {
      font-size: 0.75rem;
      color: rgba(255,255,255,0.5);
      margin-top: auto;
      padding-top: 1.5rem;
      border-top: 1px solid rgba(255,255,255,0.15);
    }
    /* 主内容区 */
    .main-content {
      flex: 1;
      background-color: var(--paper);
      overflow-x: hidden;
    }
    /* 移动端导航 */
    .mobile-nav {
      display: none;
      background: var(--ink);
      color: white;
      padding: 0.8rem 1.25rem;
      align-items: center;
      justify-content: space-between;
      position: sticky;
      top: 0;
      z-index: 60;
    }
    .hamburger {
      font-size: 1.6rem;
      background: none;
      border: none;
      color: white;
      cursor: pointer;
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: 56px;
      left: 0;
      width: 100%;
      background: var(--ink);
      flex-direction: column;
      padding: 1.5rem;
      z-index: 55;
      box-shadow: 0 10px 15px rgba(0,0,0,0.2);
    }
    .mobile-menu a {
      color: white;
      padding: 0.8rem 0;
      border-bottom: 1px solid rgba(255,255,255,0.15);
      font-weight: 500;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 2rem;
    }
    section {
      padding: 4rem 0;
    }
    h1, h2, h3 {
      font-family: var(--font-serif);
    }
    .btn-primary {
      background: var(--gold);
      color: white;
      padding: 0.75rem 1.8rem;
      border-radius: var(--radius-btn);
      font-weight: 600;
      display: inline-block;
      transition: all 0.25s;
      border: none;
      cursor: pointer;
      box-shadow: 0 4px 10px rgba(200,150,62,0.25);
    }
    .btn-primary:hover {
      background: var(--gold-dark);
      transform: translateY(-2px);
      box-shadow: 0 8px 18px rgba(166,123,46,0.3);
    }
    .btn-outline {
      background: transparent;
      border: 1px solid var(--ink);
      color: var(--ink);
      padding: 0.7rem 1.8rem;
      border-radius: var(--radius-btn);
    }
    .btn-outline:hover {
      border-color: var(--gold);
      color: var(--gold);
    }
    .card {
      background: white;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-card);
      padding: 1.8rem;
      box-shadow: var(--shadow-sm);
      transition: all 0.2s;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    @media (max-width: 768px) {
      body {
        flex-direction: column;
      }
      #main-nav {
        display: none;
      }
      .mobile-nav {
        display: flex;
      }
      .container {
        padding: 0 1.25rem;
      }
      section {
        padding: 2.5rem 0;
      }
    }