:root {
    --rc-blue: #0A3489;
    --rc-blue-mid: #1a4db5;
    --rc-blue-light: #3a6fd8;
    --rc-blue-subtle: #e8eef8;
    --rc-blue-border: #c5d3ef;
    --rc-text-primary: #1a2332;
    --rc-text-secondary: #4a5b6e;
    --rc-bg: #ffffff;
    --rc-bg-alt: #f4f7fd;
    --rc-border: #e0e7f4;
    --rc-radius: 10px;
    --rc-ease: cubic-bezier(0.22, 1, 0.36, 1);
  }

  /* ===== 顶部标题区 ===== */
  .rc_hero {
    position: relative;
    padding: 48px 24px 40px;
    text-align: center;
    background: #ffffff;
  }

  .rc_hero_inner {
    position: relative;
    z-index: 1;
    max-width: 860px;
    margin: 0 auto;
  }

  /* 要求3：顶部研究中心标题 */
  .rc_hero_title {
    color: #0A3489;
    font-size: 2.1vw !important;
    font-weight: 800;
    line-height: 1.2;
    letter-spacing: -0.02em;
    margin: 0 0 16px;
  }

  /* ===== 内容区 ===== */
  .rc_sections {
    max-width: 1200px;
    margin: 0 auto;
    padding: 32px 24px 64px;
  }

  .rc_section {
    margin-bottom: 32px;
    border: 1.5px solid var(--rc-blue-border);
    border-radius: 14px;
    overflow: hidden;
    box-shadow: 0 2px 12px rgba(10, 52, 137, 0.06);
  }

  .rc_section:last-child {
    margin-bottom: 0;
  }

  /* ===== 层级标题（升级版 — 玻璃质感图标 + 精致渐变头部） ===== */
  .rc_section_header {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 18px 26px 18px 28px;
    background:
      radial-gradient(ellipse 600px 120px at 20% 50%, rgba(10, 52, 137, 0.06) 0%, transparent 70%),
      linear-gradient(105deg, #eaf0fb 0%, #f5f7fd 35%, #fafbfe 65%, #f0f5fc 100%);
    border-bottom: 1.5px solid var(--rc-blue-border);
    position: relative;
    transition: background 0.4s var(--rc-ease), box-shadow 0.4s var(--rc-ease);
  }

  .rc_section_header:hover {
    background:
      radial-gradient(ellipse 600px 120px at 20% 50%, rgba(10, 52, 137, 0.09) 0%, transparent 70%),
      linear-gradient(105deg, #e2ebf9 0%, #eef2fa 35%, #f7f9fd 65%, #eaf2fb 100%);
    box-shadow: inset 0 0 0 1px rgba(10, 52, 137, 0.04);
  }

  /* 左侧高光蓝条 */
  .rc_section_header::before {
    content: '';
    position: absolute;
    left: 0;
    top: 6px;
    bottom: 6px;
    width: 4px;
    border-radius: 0 3px 3px 0;
    background: linear-gradient(180deg,
        var(--rc-blue-light) 0%,
        var(--rc-blue) 40%,
        var(--rc-blue-mid) 70%,
        var(--rc-blue-light) 100%);
    transition: width 0.35s var(--rc-ease), opacity 0.35s;
  }

  /* 图标 — 纯线条，无背景 */
  .rc_section_icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    flex-shrink: 0;
    transition: transform 0.35s var(--rc-ease), opacity 0.35s;
  }

  .rc_section_header:hover .rc_section_icon {
    transform: scale(1.1);
    opacity: 0.8;
  }

  .rc_section_icon img {
    width: 26px;
    height: 26px;
    display: block;
  }

  /* 标题 — 精致字距 + 微妙文字阴影 */
  .rc_section_title {
    font-size: clamp(1.05rem, 1.85vw, 1.3rem);
    font-weight: 700;
    color: var(--rc-blue);
    line-height: 1.3;
    margin: 0;
    letter-spacing: 0.03em;
    text-shadow: 0 1px 0 rgba(255, 255, 255, 0.7);
    transition: color 0.3s;
  }

  /* 右侧装饰虚线 */
  .rc_section_line {
    flex: 1;
    height: 0;
    min-width: 24px;
    border-top: 1.5px dashed rgba(10, 52, 137, 0.13);
    mask-image: linear-gradient(90deg, rgba(0, 0, 0, 0.5) 0%, rgba(0, 0, 0, 0.08) 80%, transparent 100%);
    -webkit-mask-image: linear-gradient(90deg, rgba(0, 0, 0, 0.5) 0%, rgba(0, 0, 0, 0.08) 80%, transparent 100%);
  }

  /* 卡片网格容器加内边距 */
  .rc_section .rc_grid {
    padding: 20px 22px 22px;
    background: #ffffff;
  }

  /* ===== 卡片网格 ===== */
  .rc_grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 12px;
  }

  /* 要求6：a标签；要求5：序号替代icon；要求8：纯CSS交互 */
  .rc_card {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 14px 18px;
    background: var(--rc-bg);
    border: 1px solid var(--rc-border);
    border-radius: var(--rc-radius);
    text-decoration: none;
    color: var(--rc-text-primary);
    transition:
      border-color 0.3s var(--rc-ease),
      box-shadow 0.3s var(--rc-ease),
      transform 0.3s var(--rc-ease),
      background 0.3s;
    min-height: 56px;
    position: relative;
    overflow: hidden;
  }

  .rc_card::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 3px;
    height: 100%;
    background: var(--rc-blue);
    transform: scaleY(0);
    transform-origin: center;
    transition: transform 0.3s var(--rc-ease);
    border-radius: 0 2px 2px 0;
  }

  .rc_card:hover::before {
    transform: scaleY(1);
  }

  .rc_card:hover {
    border-color: #5a84d0;
    box-shadow: 0 6px 24px rgba(10, 52, 137, 0.15);
    transform: translateY(-2px);
    background: var(--rc-bg-alt);
  }

  /* 序号徽章 */
  .rc_card_num {
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 34px;
    height: 34px;
    padding: 0 6px;
    border-radius: 8px;
    background: var(--rc-blue-subtle);
    color: var(--rc-blue);
    font-size: 0.82rem;
    font-weight: 700;
    letter-spacing: 0.01em;
    flex-shrink: 0;
    transition: background 0.3s, color 0.3s;
  }

  .rc_card:hover .rc_card_num {
    background: var(--rc-blue);
    color: #ffffff;
  }

  .rc_card_title {
    font-size: 0.97rem;
    font-weight: 600;
    color: var(--rc-text-primary);
    line-height: 1.5;
    transition: color 0.3s;
  }

  .rc_card:hover .rc_card_title {
    color: var(--rc-blue);
  }

  /* ===== 响应式 ===== */
  @media (max-width: 1024px) {
    .rc_hero_title {
      font-size: 2.8vw !important;
    }
  }

  @media (max-width: 768px) {
    .rc_hero {
      padding: 48px 20px 36px;
    }

    .rc_hero_title {
      font-size: 1.8rem !important;
    }

    .rc_sections {
      padding: 20px 16px 48px;
    }

    .rc_section {
      border-radius: 10px;
    }

    .rc_section_header {
      padding: 14px 18px 14px 22px;
    }

    .rc_section .rc_grid {
      padding: 16px;
    }

    .rc_grid {
      grid-template-columns: 1fr;
    }
  }

  @media (max-width: 480px) {
    .rc_hero_title {
      font-size: 1.5rem !important;
    }

    .rc_section_icon {
      width: 24px;
      height: 24px;
    }

    .rc_section_icon img {
      width: 22px;
      height: 22px;
    }

    .rc_section_line {
      display: none;
    }
  }