/* roulang page: index */
:root {
      --tropical-green: #2A7F4F;
      --tropical-green-deep: #236B42;
      --deep-ocean: #1A4B5C;
      --warm-sand: #D4A853;
      --soft-gray-green: #F4F7F4;
      --pure-white: #FFFFFF;
      --text-primary: #2E3A2F;
      --text-secondary: #5A6B5C;
      --text-light: #C5D6CD;
      --border-light: rgba(42, 127, 79, 0.1);
      --card-shadow: 0 4px 20px rgba(0,0,0,0.04);
      --card-shadow-hover: 0 12px 32px rgba(0,0,0,0.08);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-pill: 50px;
      --transition-default: all 0.25s ease;
    }
    * {
      box-sizing: border-box;
    }
    body {
      font-family: 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
      margin: 0;
      background-color: var(--pure-white);
      color: var(--text-primary);
      line-height: 1.75;
      display: flex;
      flex-direction: column;
      min-height: 100vh;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition-default);
    }
    button, input, textarea {
      font-family: inherit;
    }
    .main-layout {
      display: flex;
      flex: 1;
      width: 100%;
      max-width: 1440px;
      margin: 0 auto;
      position: relative;
    }
    /* 左侧竖向导航 */
    .side-nav {
      width: 240px;
      background-color: var(--deep-ocean);
      color: white;
      display: flex;
      flex-direction: column;
      padding: 2rem 1.5rem;
      position: fixed;
      top: 0;
      left: 0;
      bottom: 0;
      z-index: 40;
      box-shadow: 2px 0 15px rgba(0,0,0,0.08);
      transition: transform 0.3s ease;
    }
    .brand-area {
      margin-bottom: 2.5rem;
      padding-bottom: 1.5rem;
      border-bottom: 1px solid rgba(255,255,255,0.15);
    }
    .brand-logo {
      font-size: 1.8rem;
      font-weight: 700;
      color: var(--warm-sand);
      letter-spacing: 1px;
      display: flex;
      align-items: center;
      gap: 0.5rem;
    }
    .brand-logo i {
      font-size: 2rem;
      color: var(--tropical-green);
    }
    .brand-domain {
      font-size: 0.75rem;
      color: var(--text-light);
      margin-top: 0.25rem;
      letter-spacing: 0.3px;
    }
    .nav-menu {
      list-style: none;
      padding: 0;
      margin: 0;
      display: flex;
      flex-direction: column;
      gap: 0.5rem;
    }
    .nav-item a {
      display: block;
      padding: 0.7rem 1rem;
      border-radius: 8px;
      color: var(--text-light);
      font-weight: 500;
      font-size: 1rem;
      transition: var(--transition-default);
      position: relative;
    }
    .nav-item a:hover,
    .nav-item a.active {
      color: var(--warm-sand);
      background-color: rgba(255,255,255,0.08);
    }
    .nav-item a.active::before {
      content: '';
      position: absolute;
      left: 0;
      top: 8px;
      bottom: 8px;
      width: 4px;
      background-color: var(--warm-sand);
      border-radius: 0 4px 4px 0;
    }
    .social-icons {
      margin-top: auto;
      display: flex;
      gap: 1rem;
      padding-top: 2rem;
      color: var(--text-light);
    }
    .social-icons a {
      color: var(--text-light);
      font-size: 1.2rem;
    }
    .social-icons a:hover {
      color: var(--warm-sand);
    }
    /* 右侧内容区 */
    .content-area {
      margin-left: 240px;
      flex: 1;
      width: calc(100% - 240px);
    }
    /* 移动端顶部导航 */
    .mobile-header {
      display: none;
      background-color: var(--deep-ocean);
      color: white;
      padding: 1rem 1.5rem;
      position: sticky;
      top: 0;
      z-index: 50;
      align-items: center;
      justify-content: space-between;
    }
    .mobile-brand {
      font-size: 1.4rem;
      font-weight: 700;
      color: var(--warm-sand);
    }
    #menu-toggle {
      background: none;
      border: none;
      color: white;
      font-size: 1.8rem;
      cursor: pointer;
    }
    .mobile-menu {
      display: none;
      flex-direction: column;
      background-color: var(--deep-ocean);
      position: fixed;
      top: 60px;
      left: 0;
      right: 0;
      bottom: 0;
      padding: 2rem;
      z-index: 45;
      gap: 0.8rem;
    }
    .mobile-menu a {
      color: var(--text-light);
      font-size: 1.2rem;
      padding: 0.8rem;
      border-radius: 8px;
    }
    .mobile-menu a:hover,
    .mobile-menu a.active {
      color: var(--warm-sand);
      background: rgba(255,255,255,0.1);
    }
    /* 通用板块 */
    .section-padding {
      padding: 5rem 2rem;
    }
    .container-inner {
      max-width: 1100px;
      margin: 0 auto;
    }
    h1 {
      font-size: 3rem;
      font-weight: 700;
      line-height: 1.2;
      letter-spacing: -0.5px;
      color: var(--text-primary);
    }
    h2 {
      font-size: 2.25rem;
      font-weight: 600;
      line-height: 1.3;
      margin-bottom: 2.5rem;
      color: var(--deep-ocean);
      position: relative;
      display: inline-block;
    }
    h2::after {
      content: '';
      position: absolute;
      left: 0;
      bottom: -8px;
      width: 60px;
      height: 4px;
      background-color: var(--tropical-green);
      border-radius: 2px;
    }
    h3 {
      font-size: 1.375rem;
      font-weight: 600;
      line-height: 1.4;
      color: var(--text-primary);
    }
    .btn-primary {
      background-color: var(--tropical-green);
      color: white;
      padding: 0.875rem 2rem;
      border-radius: var(--radius-btn);
      font-weight: 600;
      display: inline-block;
      text-align: center;
      transition: var(--transition-default);
      border: none;
      cursor: pointer;
    }
    .btn-primary:hover {
      background-color: var(--tropical-green-deep);
      transform: translateY(-2px);
      box-shadow: 0 8px 16px rgba(42,127,79,0.2);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--deep-ocean);
      color: var(--deep-ocean);
      padding: 0.875rem 2rem;
      border-radius: var(--radius-btn);
      font-weight: 600;
      display: inline-block;
      transition: var(--transition-default);
    }
    .btn-outline:hover {
      background-color: var(--deep-ocean);
      color: white;
    }
    .btn-cta {
      background-color: var(--warm-sand);
      color: var(--text-primary);
      padding: 0.9rem 2.5rem;
      border-radius: var(--radius-pill);
      font-weight: 700;
      box-shadow: 0 8px 20px rgba(212,168,83,0.25);
      transition: var(--transition-default);
      display: inline-block;
    }
    .btn-cta:hover {
      background-color: #c49a3e;
      transform: translateY(-2px);
    }
    .card {
      background: var(--pure-white);
      border-radius: var(--radius-card);
      box-shadow: var(--card-shadow);
      padding: 2rem;
      transition: var(--transition-default);
      border: 1px solid var(--border-light);
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--card-shadow-hover);
      border-top: 4px solid var(--warm-sand);
    }
    .stat-number {
      font-size: 2.5rem;
      font-weight: 700;
      color: var(--tropical-green);
      line-height: 1.2;
    }
    /* FAQ 手风琴 */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
    }
    .faq-question {
      background: var(--soft-gray-green);
      padding: 1.2rem 1.5rem;
      font-weight: 600;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 0.8rem;
      transition: background 0.2s;
    }
    .faq-question:hover {
      background: #e8f0e8;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      background: white;
      padding: 0 1.5rem;
      border-left: 4px solid var(--tropical-green);
      margin-left: 0;
    }
    .faq-answer.open {
      max-height: 200px;
      padding: 1.2rem 1.5rem;
    }
    footer {
      background-color: var(--deep-ocean);
      color: var(--text-light);
      padding: 3rem 2rem 1.5rem;
    }
    /* 响应式 */
    @media (max-width: 1024px) {
      .side-nav {
        display: none;
      }
      .content-area {
        margin-left: 0;
        width: 100%;
      }
      .mobile-header {
        display: flex;
      }
      .mobile-menu.show {
        display: flex;
      }
      h1 {
        font-size: 2.2rem;
      }
      h2 {
        font-size: 1.8rem;
      }
    }
    @media (max-width: 768px) {
      .section-padding {
        padding: 3rem 1.5rem;
      }
      .card {
        padding: 1.5rem;
      }
    }