:root {
      --primary: #2563eb;
      --primary-light: #eff6ff;
      --primary-hover: #1d4ed8;
      --text: #1f2937;
      --text-muted: #6b7280;
      --bg: #f8fafc;
      --card: #ffffff;
      --border: #e2e8f0;
      --shadow: 0 10px 30px rgba(37, 99, 235, 0.08);
      --radius: 16px;}

  

    .section {
      max-width: 1400px;
      margin: 0 auto;}

    .section-header {
      text-align: center;
      margin-bottom: 40px;}

    .section-header h2 {
      font-size: 32px;
      font-weight: 700;
      color: var(--text);
      margin-bottom: 12px;}

    .section-header p {
      font-size: 16px;
      color: var(--text-muted);}

    /* Group image tabs */
    .tabs {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
      
      margin-top: 26px;
      padding: 16px 0 30px;}

    .tab {
      position: relative;
      padding: 0;
      border: 3px solid transparent;
      border-radius: var(--radius);
      overflow: hidden;
      background: none;
      cursor: pointer;
      box-shadow: var(--shadow);
      opacity: 0.5;
      filter: grayscale(45%);
      transform: scale(0.92);
      transition: transform 0.35s ease, box-shadow 0.35s ease, border-color 0.35s ease, opacity 0.35s ease, filter 0.35s ease;}

    .tab img {
      width: 100%;
      aspect-ratio: 16 / 9;
      object-fit: cover;
      display: block;}

    .tab:hover {
      transform: scale(0.97) translateY(-3px);
      opacity: 0.9;
      filter: grayscale(0);
      box-shadow: 0 14px 32px rgba(37, 99, 235, 0.18);}

    .tab.active {
      border-color: var(--tab-color, var(--primary));
      transform: scale(1.16) translateY(-6px);
      opacity: 1;
      filter: none;
      box-shadow: 0 22px 46px rgba(37, 99, 235, 0.32);
      z-index: 3;}

    /* 指向下方赛道的三角指示器 */
    .tab.active::before {
      content: "";
      position: absolute;
      bottom: 0;
      left: 50%;
      transform: translateX(-50%);
      width: 0;
      height: 0;
      border-left: 15px solid transparent;
      border-right: 15px solid transparent;
      border-bottom: 15px solid var(--tab-color, var(--primary));
      z-index: 2;}

    .tab.active::after {
      content: "";
      position: absolute;
      top: 12px;
      right: 12px;
      width: 30px;
      height: 30px;
      border-radius: 50%;
      background: var(--tab-color, var(--primary)) url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="white"><path d="M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z"/></svg>') center / 18px no-repeat;
      box-shadow: 0 4px 12px rgba(37, 99, 235, 0.45);
      z-index: 2;}

    /* 初始默认态：三张图等大、等亮 */
    .tabs.is-idle .tab {
      transform: scale(1);
      opacity: 1;
      filter: none;}

    .tabs.is-idle .tab:hover {
      transform: scale(1.03) translateY(-3px);}

    /* 赛道区标题：与赛组关联 */
    .tracks-caption {
      grid-column: 1 / -1;
      display: flex;
      align-items: center;
      gap: 10px;
      margin-bottom: 4px;}

    .caption-dot {
      width: 10px;
      height: 10px;
      border-radius: 50%;
      background: var(--group-color, var(--primary));
      box-shadow: 0 0 0 4px var(--group-light, var(--primary-light));}

    .caption-text {
      font-size: 22px;
      font-weight: 600;
      color: var(--text);}

    .caption-count {
      font-size: 22px;
      color: var(--text-muted);}

    /* Tracks grid */
    .tracks-wrapper {
      position: relative;
      min-height: 260px;
      transform-origin: top center;}

    .tracks {
      display: none;
      grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
      gap: 24px;
      animation: zoomIn 0.45s ease;}

    .tracks.active {
      display: grid;}

    @keyframes zoomIn {
      from {
        opacity: 0;
        transform: scale(0.94) translateY(10px);}
      to {
        opacity: 1;
        transform: scale(1) translateY(0);}
    }

    .track-card {
      background: var(--card);
      border: 1px solid var(--border);
      border-radius: var(--radius);
      padding: 28px;
      box-shadow: var(--shadow);
      transition: all 0.3s ease;
      position: relative;
      overflow: hidden;}

    .track-card::before {
      content: "";
      position: absolute;
      top: 0;
      left: 0;
      width: 4px;
      height: 100%;
      background: var(--group-color, var(--primary));
      transform: scaleY(0);
      transition: transform 0.3s ease;}

    .track-card:hover {
      transform: translateY(-6px);
      box-shadow: 0 18px 40px rgba(37, 99, 235, 0.12);}

    .track-card:hover::before {
      transform: scaleY(1);}

    .track-icon {
      width: 48px;
      height: 48px;
      background: var(--group-light, var(--primary-light));
      border-radius: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 18px;}
.track-icon img{
    width: auto;
    height: 50px;
}
    .track-icon svg {
      width: 24px;
      height: 24px;
      fill: var(--group-color, var(--primary));}

    .track-title {
      font-size: 24px;
      font-weight: 600;
      color: var(--text);
      margin-bottom: 8px;}

    .track-desc {
      font-size: 16px;
      color: var(--text-muted);
      line-height: 1.6;}

    /* Detail button */
    .detail-btn-wrapper {
      display: flex;
      justify-content: center;
      margin-top: 40px;}

    .detail-btn {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      padding: 14px 40px;
      background: var(--card);
      color: var(--primary);
      border: 1px solid var(--primary);
      border-radius: 999px;
      font-size: 16px;
      font-weight: 600;
      text-decoration: none;
      cursor: pointer;
      transition: all 0.3s ease;}

    .detail-btn svg {
      width: 18px;
      height: 18px;
      fill: currentColor;
      transition: transform 0.3s ease;}

    .detail-btn:hover {
      background: var(--primary);
      color: #fff;
      box-shadow: 0 8px 20px rgba(37, 99, 235, 0.25);
      transform: translateY(-2px);}

    .detail-btn:hover svg {
      transform: translateX(4px);}

    /* Responsive */
    @media (max-width: 768px) {
      body {
        padding: 0;
        }

      .section-header h2 {
        font-size: 24px;}

      .tabs {

        gap: 10px;
        padding: 10px 0 20px;}

      .tab {
        transform: scale(0.95);}

      .tabs.is-idle .tab {
        transform: scale(1);}

      .tabs.is-idle .tab:hover {
        transform: scale(1.02) translateY(-2px);}

      .tab:hover {
        transform: scale(0.99) translateY(-2px);}

      .tab.active {
        transform: scale(1.09) translateY(-4px);}

      .tab.active::before {
        border-left-width: 10px;
        border-right-width: 10px;
        border-bottom-width: 10px;}

      .tab.active::after {
        top: 6px;
        right: 6px;
        width: 20px;
        height: 20px;
        background-size: 12px;}

      .caption-text {
        font-size: 22px;}

      .tracks {
        grid-template-columns: 1fr;
        gap: 16px;}

      .track-card {
        padding: 22px;}

      .detail-btn-wrapper {
        margin-top: 28px;}

      .detail-btn {
        padding: 12px 32px;
        font-size: 15px;}
    }