/* roulang page: index */
:root {
      --primary: #E94E1B;      /* 斗战橙红 */
      --primary-dark: #C43D14;
      --secondary: #1B1B1B;    /* 深岩黑 */
      --accent: #F5A623;       /* 金箍棒金 */
      --warm-bg: #F5F0E8;      /* 暖沙白 */
      --white: #FFFFFF;
      --text-main: #1B1B1B;
      --text-secondary: #444444;
      --text-muted: #6B7280;
      --border-light: rgba(0,0,0,0.04);
      --shadow-sm: 0 2px 12px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.08);
      --shadow-lg: 0 16px 32px rgba(0,0,0,0.1);
      --radius-card: 16px;
      --radius-btn: 8px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --transition: 0.25s ease;
      --container-max: 1280px;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--warm-bg);
      color: var(--text-main);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
      transition: background-color 0.2s;
    }

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

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

    button, input {
      font-family: inherit;
    }

    .container {
      max-width: var(--container-max);
      margin-left: auto;
      margin-right: auto;
      padding-left: 24px;
      padding-right: 24px;
    }

    /* 导航卡片化面板 */
    .nav-panel {
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(8px);
      border-radius: 16px;
      box-shadow: var(--shadow-sm);
      padding: 12px 24px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      flex-wrap: wrap;
      margin-top: 20px;
      border: 1px solid rgba(0,0,0,0.03);
    }

    .nav-logo {
      font-weight: 800;
      font-size: 1.5rem;
      letter-spacing: -0.3px;
      color: var(--primary);
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .nav-logo i {
      font-size: 1.8rem;
      color: var(--accent);
    }

    .nav-links {
      display: flex;
      gap: 8px;
      flex-wrap: wrap;
      align-items: center;
    }

    .nav-item {
      background: transparent;
      border-radius: 8px;
      padding: 8px 16px;
      font-weight: 600;
      font-size: 0.95rem;
      color: var(--secondary);
      transition: all var(--transition);
      display: flex;
      align-items: center;
      gap: 6px;
    }
    .nav-item i {
      font-size: 1rem;
      color: var(--text-muted);
    }
    .nav-item:hover {
      background: rgba(233,78,27,0.08);
      color: var(--primary);
      transform: translateY(-1px);
    }

    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      font-size: 1rem;
      letter-spacing: 0.3px;
      border: none;
      cursor: pointer;
      transition: all var(--transition);
      display: inline-flex;
      align-items: center;
      gap: 8px;
      box-shadow: 0 4px 10px rgba(233,78,27,0.25);
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      transform: scale(1.02);
      box-shadow: 0 8px 18px rgba(233,78,27,0.35);
    }

    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      transition: all var(--transition);
      display: inline-flex;
      align-items: center;
      gap: 8px;
    }
    .btn-outline:hover {
      background: rgba(233,78,27,0.1);
      transform: translateY(-2px);
    }

    /* 卡片通用 */
    .card {
      background: var(--white);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      border: 1px solid var(--border-light);
      transition: all var(--transition);
    }
    .card:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-4px);
    }

    /* 指标数字 */
    .metric-number {
      font-size: 2.8rem;
      font-weight: 800;
      letter-spacing: -0.5px;
      color: var(--accent);
      line-height: 1.2;
    }

    /* FAQ 手风琴 */
    .faq-item {
      background: var(--white);
      border-radius: 12px;
      padding: 16px 24px;
      margin-bottom: 12px;
      border: 1px solid rgba(0,0,0,0.03);
      cursor: pointer;
      transition: all 0.2s;
    }
    .faq-question {
      font-weight: 700;
      display: flex;
      justify-content: space-between;
      align-items: center;
      color: var(--secondary);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease, padding 0.2s;
      color: var(--text-secondary);
      padding-top: 0;
    }
    .faq-item.active .faq-answer {
      max-height: 300px;
      padding-top: 14px;
    }
    .faq-item.active .faq-icon {
      transform: rotate(180deg);
      color: var(--primary);
    }

    /* 对比褪色/高亮 */
    .compare-old {
      opacity: 0.7;
      background: #f3f4f6;
      filter: grayscale(20%);
    }
    .compare-new {
      background: #fff6f2;
      border-left: 4px solid var(--primary);
      box-shadow: var(--shadow-sm);
    }

    /* 汉堡菜单 */
    .mobile-menu {
      display: none;
      flex-direction: column;
      background: white;
      border-radius: 24px;
      box-shadow: var(--shadow-lg);
      position: absolute;
      top: 85px;
      right: 24px;
      width: 260px;
      padding: 20px;
      z-index: 50;
    }
    .mobile-menu a {
      padding: 14px 12px;
      display: block;
      font-weight: 600;
      border-radius: 12px;
      margin-bottom: 4px;
    }
    @media (max-width: 768px) {
      .desktop-nav { display: none; }
      .mobile-toggle { display: flex; }
      .nav-panel { padding: 12px 20px; }
    }

    @media (min-width: 769px) {
      .mobile-toggle { display: none; }
      .mobile-menu { display: none; }
    }

    /* 表单 */
    .input-field {
      border: 1px solid #d1d5db;
      border-radius: 8px;
      padding: 12px 16px;
      width: 100%;
      transition: border 0.2s;
    }
    .input-field:focus {
      outline: none;
      border-color: var(--primary);
      box-shadow: 0 0 0 3px rgba(233,78,27,0.1);
    }

    footer {
      background: var(--secondary);
      color: #e5e7eb;
    }