/* roulang page: index */
:root {
      --primary-black: #1A1A1A;
      --accent-gold: #D4AF37;
      --bg-warm: #FAF9F6;
      --deep-green: #2E4A3A;
      --card-bg: #F5F2EB;
      --border-soft: #E8E4DB;
      --text-gray: #6B6B6B;
      --text-dark: #3A3A3A;
      --white: #FFFFFF;
      --font-serif: 'Noto Serif SC', 'Times New Roman', serif;
      --font-sans: 'Noto Sans SC', 'Inter', system-ui, -apple-system, sans-serif;
      --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
      --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.08);
      --radius-card: 8px;
      --transition-smooth: 0.25s ease;
      --container-max: 1280px;
      --section-gap: 100px;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--bg-warm);
      color: var(--text-gray);
      line-height: 1.75;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color var(--transition-smooth);
    }
    button, .btn {
      cursor: pointer;
      font-family: var(--font-sans);
      border: none;
      background: transparent;
    }
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
      width: 100%;
    }
    /* 导航系统 - 资讯门户吸顶风格 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      background: var(--primary-black);
      transition: all 0.3s ease;
      backdrop-filter: blur(0px);
    }
    .header-brand-row {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 56px;
      padding: 0 24px;
      border-bottom: 1px solid rgba(255,255,255,0.08);
    }
    .logo {
      font-family: var(--font-serif);
      font-size: 1.5rem;
      font-weight: 700;
      color: var(--white);
      letter-spacing: 0.04em;
      white-space: nowrap;
    }
    .logo .gold-dot {
      color: var(--accent-gold);
    }
    .search-trigger {
      background: none;
      border: none;
      color: var(--white);
      font-size: 1.4rem;
      width: 44px;
      height: 44px;
      display: flex;
      align-items: center;
      justify-content: center;
      transition: color 0.2s;
    }
    .search-trigger:hover {
      color: var(--accent-gold);
    }
    .search-bar {
      position: absolute;
      top: 100%;
      left: 0;
      width: 100%;
      background: var(--primary-black);
      padding: 0 24px;
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease, padding 0.2s;
      display: flex;
      align-items: center;
    }
    .search-bar.active {
      max-height: 70px;
      padding: 12px 24px;
    }
    .search-bar input {
      width: 100%;
      background: transparent;
      border: none;
      border-bottom: 2px solid var(--accent-gold);
      color: var(--white);
      font-size: 1rem;
      padding: 10px 0;
      outline: none;
    }
    .nav-channels {
      display: flex;
      align-items: center;
      height: 44px;
      padding: 0 24px;
      gap: 32px;
      overflow-x: auto;
      white-space: nowrap;
    }
    .nav-channels a {
      color: var(--white);
      font-size: 0.875rem;
      font-weight: 500;
      letter-spacing: 0.04em;
      padding: 12px 0;
      border-bottom: 2px solid transparent;
      transition: border-color 0.3s, color 0.2s;
      flex-shrink: 0;
    }
    .nav-channels a:hover,
    .nav-channels a.active {
      border-bottom-color: var(--accent-gold);
      color: var(--accent-gold);
    }
    .mobile-menu-toggle {
      display: none;
      background: none;
      border: none;
      color: var(--white);
      font-size: 1.8rem;
      width: 44px;
      height: 44px;
      align-items: center;
      justify-content: center;
    }
    @media (max-width: 991px) {
      .nav-channels {
        display: none;
        position: absolute;
        top: 56px;
        left: 0;
        width: 100%;
        background: rgba(26,26,26,0.98);
        flex-direction: column;
        align-items: flex-start;
        gap: 0;
        padding: 16px 24px;
        backdrop-filter: blur(12px);
      }
      .nav-channels.mobile-open {
        display: flex;
      }
      .nav-channels a {
        padding: 14px 0;
        width: 100%;
        border-bottom: 1px solid rgba(255,255,255,0.1);
      }
      .mobile-menu-toggle {
        display: flex;
      }
      .header-brand-row {
        justify-content: space-between;
      }
    }
    .scrolled .site-header {
      background: rgba(26,26,26,0.97);
      backdrop-filter: blur(12px);
      box-shadow: 0 4px 20px rgba(0,0,0,0.2);
    }
    .scrolled .header-brand-row {
      height: 56px;
      border-bottom: none;
    }
    .scrolled .nav-channels {
      height: 44px;
    }
    @media (min-width: 992px) {
      .scrolled .header-brand-row {
        height: 56px;
      }
      .scrolled .nav-channels {
        display: flex;
      }
    }
    /* 板块通用 */
    section {
      padding: var(--section-gap) 0;
    }
    .section-title {
      font-family: var(--font-serif);
      font-size: 2.25rem;
      font-weight: 600;
      color: var(--text-dark);
      margin-bottom: 0.5rem;
      position: relative;
      display: inline-block;
    }
    .section-title::after {
      content: '';
      display: block;
      width: 40px;
      height: 2px;
      background: var(--accent-gold);
      margin-top: 8px;
    }
    .section-sub {
      font-size: 1.125rem;
      color: var(--text-gray);
      margin-bottom: 2.5rem;
      max-width: 600px;
    }
    .bg-soft {
      background-color: var(--card-bg);
    }
    /* Hero */
    .hero {
      padding: 140px 0 80px;
      display: flex;
      align-items: center;
      min-height: 85vh;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .hero-content h1 {
      font-family: var(--font-serif);
      font-size: 3rem;
      font-weight: 700;
      line-height: 1.15;
      letter-spacing: -0.02em;
      color: var(--primary-black);
      margin-bottom: 1.5rem;
    }
    .hero-sub {
      color: var(--accent-gold);
      font-size: 1rem;
      letter-spacing: 0.08em;
      font-weight: 500;
      margin-bottom: 2rem;
    }
    .btn-group {
      display: flex;
      flex-wrap: wrap;
      gap: 16px;
    }
    .btn-primary {
      background: var(--deep-green);
      color: var(--accent-gold);
      padding: 14px 32px;
      border-radius: 4px;
      font-weight: 600;
      transition: all 0.2s;
      border: 1px solid transparent;
      display: inline-block;
      text-align: center;
    }
    .btn-primary:hover {
      background: #1F3A2C;
      transform: scale(1.02);
      box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    }
    .btn-outline {
      border: 1px solid var(--accent-gold);
      color: var(--primary-black);
      padding: 14px 32px;
      border-radius: 4px;
      font-weight: 600;
      transition: all 0.2s;
      background: transparent;
    }
    .btn-outline:hover {
      background: rgba(212, 175, 55, 0.1);
      transform: scale(1.02);
    }
    .hero-image {
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      border-radius: var(--radius-card);
      height: 450px;
      position: relative;
      overflow: hidden;
      box-shadow: var(--shadow-md);
    }
    @media (max-width: 768px) {
      .hero-grid {
        grid-template-columns: 1fr;
      }
      .hero-content h1 {
        font-size: 2rem;
      }
      .hero-image {
        height: 280px;
      }
      section {
        padding: 60px 0;
      }
    }
    /* 卡片网格 */
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .card {
      background: var(--white);
      border: 1px solid var(--border-soft);
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--shadow-sm);
      transition: all var(--transition-smooth);
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    .card-icon {
      font-size: 2rem;
      color: var(--accent-gold);
      margin-bottom: 1rem;
    }
    .card h3 {
      font-size: 1.375rem;
      font-weight: 600;
      color: var(--text-dark);
      margin-bottom: 0.75rem;
    }
    .learn-more {
      color: var(--deep-green);
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      margin-top: 1rem;
      transition: gap 0.2s;
    }
    .learn-more:hover {
      gap: 8px;
    }
    @media (max-width: 991px) {
      .grid-3 { grid-template-columns: repeat(2, 1fr); }
    }
    @media (max-width: 576px) {
      .grid-3 { grid-template-columns: 1fr; }
    }
    /* 挑战板块 */
    .challenge-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 40px;
      align-items: center;
    }
    .challenge-list {
      display: flex;
      flex-direction: column;
      gap: 28px;
    }
    .challenge-item {
      display: flex;
      gap: 16px;
    }
    .challenge-num {
      font-size: 2rem;
      font-weight: 700;
      color: var(--accent-gold);
      line-height: 1;
    }
    .challenge-text h4 {
      font-weight: 600;
      color: var(--text-dark);
    }
    .challenge-img {
      background: url('/assets/images/backpic/back-2.webp') center/cover;
      border-radius: var(--radius-card);
      height: 320px;
    }
    @media (max-width: 768px) {
      .challenge-row { grid-template-columns: 1fr; }
    }
    /* 数据 */
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
      text-align: center;
    }
    .stat-item {
      background: transparent;
      padding: 24px 16px;
      border-bottom: 2px solid var(--accent-gold);
    }
    .stat-number {
      font-size: 3rem;
      font-weight: 700;
      color: var(--deep-green);
      line-height: 1.2;
    }
    @media (max-width: 768px) {
      .stats-grid { grid-template-columns: repeat(2, 1fr); }
    }
    /* 证言 */
    .testimonial-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 24px;
    }
    .testimonial-card {
      background: var(--white);
      border-radius: var(--radius-card);
      padding: 28px;
      border-left: 4px solid var(--accent-gold);
    }
    @media (max-width: 768px) {
      .testimonial-grid { grid-template-columns: 1fr; }
    }
    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border-soft);
      margin-bottom: 8px;
    }
    .faq-question {
      width: 100%;
      text-align: left;
      padding: 18px 0;
      font-weight: 600;
      font-size: 1.125rem;
      color: var(--text-dark);
      display: flex;
      justify-content: space-between;
      align-items: center;
      background: transparent;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      background: var(--card-bg);
      padding: 0 20px;
    }
    .faq-answer.open {
      max-height: 200px;
      padding: 20px;
    }
    /* CTA */
    .cta-dark {
      background: var(--primary-black);
      color: var(--white);
      text-align: center;
      padding: 80px 0;
    }
    .cta-dark h2 {
      color: white;
    }
    .footer {
      background: var(--primary-black);
      color: #ccc;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
    }
    @media (max-width: 768px) {
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }
    .animate-on-scroll {
      opacity: 0;
      transform: translateY(20px);
      transition: opacity 0.6s ease, transform 0.6s ease;
    }
    .visible {
      opacity: 1;
      transform: translateY(0);
    }