/* roulang page: index */
/* 设计变量与全局重置 */
    :root {
      --color-primary: #1A1F36;
      --color-accent: #C8A96E;
      --color-accent-hover: #B8944F;
      --color-bg: #FAF8F5;
      --color-dark: #0F1322;
      --color-white: #FFFFFF;
      --color-border: #E8E4DD;
      --color-text: #1A1F36;
      --color-text-soft: #4A4F63;
      --color-text-light: #6B7083;
      --color-nav-text: #8A8FA3;
      --color-nav-active: #FFFFFF;
      --font-heading: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
      --font-body: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
      --font-number: "Inter", "SF Pro Display", sans-serif;
      --radius-card: 12px;
      --radius-button: 8px;
      --radius-tag: 6px;
      --shadow-card: 0 2px 12px rgba(26, 31, 54, 0.04);
      --shadow-card-hover: 0 8px 28px rgba(26, 31, 54, 0.08);
      --transition-smooth: 0.25s cubic-bezier(0.25, 0.46, 0.45, 0.94);
      --nav-width: 240px;
      --nav-collapsed: 64px;
    }

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

    html {
      scroll-behavior: smooth;
      background-color: var(--color-bg);
    }

    body {
      font-family: var(--font-body);
      background-color: var(--color-bg);
      color: var(--color-text);
      line-height: 1.7;
      font-size: 16px;
      display: flex;
      min-height: 100vh;
      -webkit-font-smoothing: antialiased;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s;
    }

    button {
      font-family: inherit;
      cursor: pointer;
      border: none;
      background: none;
    }

    /* 左侧竖向导航（桌面端） */
    .side-nav {
      position: fixed;
      left: 0;
      top: 0;
      width: var(--nav-width);
      height: 100vh;
      background-color: var(--color-primary);
      display: flex;
      flex-direction: column;
      z-index: 1000;
      transition: width 0.3s ease;
      padding: 32px 0 24px;
      box-shadow: 2px 0 12px rgba(0,0,0,0.06);
    }

    .nav-brand {
      display: flex;
      align-items: center;
      justify-content: center;
      height: 80px;
      padding: 0 20px;
      margin-bottom: 48px;
    }

    .logo-text {
      font-family: var(--font-heading);
      font-weight: 700;
      font-size: 1.5rem;
      letter-spacing: 0.04em;
      color: var(--color-accent);
      white-space: nowrap;
    }

    .nav-links {
      flex: 1;
      display: flex;
      flex-direction: column;
      gap: 8px;
      padding: 0 20px;
    }

    .nav-link {
      display: flex;
      align-items: center;
      color: var(--color-nav-text);
      font-weight: 500;
      font-size: 0.95rem;
      padding: 10px 16px;
      border-radius: 8px;
      position: relative;
      transition: all 0.2s ease;
      border-left: 3px solid transparent;
    }

    .nav-link:hover {
      color: var(--color-accent);
      background-color: rgba(255,255,255,0.04);
    }

    .nav-link.active {
      color: var(--color-nav-active);
      background-color: rgba(255,255,255,0.06);
      border-left: 3px solid var(--color-accent);
    }

    .nav-footer {
      padding: 24px 20px 8px;
      font-size: 0.75rem;
      color: #5A5F73;
      border-top: 1px solid rgba(255,255,255,0.08);
      margin-top: auto;
    }

    /* 右侧内容区 */
    .main-content {
      margin-left: var(--nav-width);
      flex: 1;
      width: 100%;
      transition: margin-left 0.3s ease;
    }

    .container {
      max-width: 1040px;
      margin: 0 auto;
      padding: 0 32px;
    }

    section {
      padding: 120px 0;
    }

    /* 移动端顶部导航 */
    .mobile-header {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 56px;
      background-color: var(--color-primary);
      z-index: 1100;
      align-items: center;
      justify-content: space-between;
      padding: 0 20px;
      box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    }

    .mobile-logo {
      font-weight: 700;
      font-size: 1.2rem;
      color: var(--color-accent);
    }

    .hamburger {
      display: flex;
      flex-direction: column;
      gap: 5px;
      width: 24px;
      height: 18px;
      justify-content: center;
    }

    .hamburger span {
      display: block;
      height: 2px;
      background: #FFFFFF;
      border-radius: 2px;
      transition: 0.2s;
    }

    .mobile-menu {
      display: none;
      position: fixed;
      top: 56px;
      left: 0;
      width: 100%;
      background: var(--color-primary);
      flex-direction: column;
      padding: 16px;
      gap: 8px;
      z-index: 1050;
      box-shadow: 0 8px 20px rgba(0,0,0,0.2);
    }

    .mobile-menu.active {
      display: flex;
    }

    .mobile-menu a {
      color: var(--color-nav-text);
      padding: 12px 16px;
      font-weight: 500;
      border-radius: 8px;
    }

    .mobile-menu a:hover {
      background: rgba(255,255,255,0.05);
      color: var(--color-accent);
    }

    /* 排版组件 */
    h1 {
      font-family: var(--font-heading);
      font-size: clamp(2.6rem, 5vw, 4.5rem);
      font-weight: 700;
      letter-spacing: -0.02em;
      color: var(--color-primary);
      line-height: 1.2;
    }

    h2 {
      font-family: var(--font-heading);
      font-size: clamp(2rem, 4vw, 2.8rem);
      font-weight: 600;
      color: var(--color-primary);
      margin-bottom: 16px;
      position: relative;
      display: inline-block;
    }

    .section-title-wrapper {
      margin-bottom: 56px;
    }

    .decor-line {
      width: 40px;
      height: 4px;
      background-color: var(--color-accent);
      margin-top: 8px;
      border-radius: 2px;
    }

    h3 {
      font-family: var(--font-heading);
      font-size: 1.35rem;
      font-weight: 500;
      color: var(--color-primary);
    }

    p {
      max-width: 68ch;
      color: var(--color-text-soft);
    }

    .text-number {
      font-family: var(--font-number);
      font-weight: 700;
      color: var(--color-accent);
    }

    /* 卡片 */
    .card {
      background: var(--color-white);
      border: 1px solid var(--color-border);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      transition: transform 0.3s cubic-bezier(0.25,0.46,0.45,0.94), box-shadow 0.3s;
      overflow: hidden;
    }

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

    .btn-primary {
      background: var(--color-accent);
      color: var(--color-primary);
      font-weight: 600;
      border-radius: var(--radius-button);
      height: 48px;
      padding: 0 48px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: all 0.2s ease;
      font-size: 1rem;
      letter-spacing: 0.02em;
    }

    .btn-primary:hover {
      background: var(--color-accent-hover);
      transform: translateY(-1px);
      box-shadow: 0 6px 20px rgba(200, 169, 110, 0.25);
    }

    .text-link {
      color: var(--color-primary);
      font-weight: 500;
      border-bottom: 1px solid var(--color-primary);
      transition: all 0.2s;
      display: inline-block;
    }

    .text-link:hover {
      border-color: var(--color-accent);
      color: var(--color-accent);
      transform: translateX(4px);
    }

    /* Hero悬浮CTA */
    .floating-cta {
      position: fixed;
      bottom: 32px;
      right: 32px;
      background: var(--color-accent);
      color: var(--color-primary);
      font-weight: 600;
      padding: 12px 28px;
      border-radius: 40px;
      box-shadow: 0 6px 18px rgba(0,0,0,0.1);
      z-index: 99;
      transition: opacity 0.3s;
      display: none;
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--color-border);
    }

    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 20px 0;
      font-weight: 500;
      cursor: pointer;
      transition: background 0.2s;
    }

    .faq-question:hover {
      background: #FAF8F5;
    }

    .faq-icon {
      font-size: 1.4rem;
      transition: transform 0.25s;
      color: var(--color-primary);
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease;
      color: var(--color-text-soft);
      font-size: 0.95rem;
    }

    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-bottom: 20px;
    }

    .faq-item.open .faq-icon {
      transform: rotate(45deg);
      color: var(--color-accent);
    }

    /* 页脚 */
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }

    @media (max-width: 1024px) {
      .side-nav {
        width: var(--nav-collapsed);
        padding: 24px 0;
      }
      .nav-brand .logo-text {
        font-size: 1.2rem;
      }
      .nav-links .nav-link span {
        display: none;
      }
      .main-content {
        margin-left: var(--nav-collapsed);
      }
      .container {
        padding: 0 24px;
      }
    }

    @media (max-width: 768px) {
      .side-nav {
        display: none;
      }
      .mobile-header {
        display: flex;
      }
      .main-content {
        margin-left: 0;
        padding-top: 56px;
      }
      section {
        padding: 80px 0;
      }
      .footer-grid {
        grid-template-columns: 1fr;
        gap: 32px;
      }
      .floating-cta {
        display: none !important;
      }
    }

    /* 动画 */
    @keyframes fadeInUp {
      from { opacity: 0; transform: translateY(18px); }
      to { opacity: 1; transform: translateY(0); }
    }
    .animate-in {
      animation: fadeInUp 0.7s ease forwards;
    }