:root {
    --primary: #2D68D5;
    --primary-light: #EEF2FF;
    --text: #1E293B;
    --text-secondary: #64748B;
    --bg: #F8FAFC;
    --card-bg: #FFFFFF;
    --border: #E2E8F0;
    --hover-bg: #F1F5F9;
    --shadow: 0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.06);
    --shadow-lg: 0 20px 25px -5px rgba(0,0,0,.1), 0 10px 10px -5px rgba(0,0,0,.04);
    --radius: 12px;
  }
  /*.container {*/
     
  /*  width: 100%;*/
  /*  max-width: 1200px;*/
  /*}*/
.header {
    text-align: center;
    margin-bottom: 40px;
  }
  .header h1 {
    font-size: 28px;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 8px;
  }
  .header p {
    font-size: 15px;
    color: var(--text-secondary);
  }

  /* Tab 导航 */
  .tab-nav {
    display: flex;
    gap: 4px;
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 5px;
    box-shadow: var(--shadow);
    margin-bottom: 24px;
    border: 1px solid var(--border);
  }
  .tab-btn {
    flex: 1;
    padding: 12px 20px;
    border: none;
    background: transparent;
    border-radius: 10px;
    font-size: 14px;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all .2s ease;
    white-space: nowrap;
  }
  .tab-btn:hover {
    color: var(--text);
    background: var(--hover-bg);
  }
  .tab-btn.active {
    background: var(--primary);
    color: #FFFFFF;
    box-shadow: 0 2px 8px rgba(79,70,229,.3);
  }

  /* QA 列表 */
  .qa-list {
    display: flex;
    flex-direction: column;
    gap: 2px;
  }

  /* QA 卡片 */
  .qa-card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px 24px;
    cursor: default;
    transition: all .2s ease;
    position: relative;
  }
  .qa-card.hidden {
    display: none;
  }
  .qa-card:hover {
    background: #FAFBFF;
    border-color: #C7D2FE;
    box-shadow: var(--shadow);
    z-index: 10;
  }

  /* 问题行 */
  .qa-question {
    display: flex;
    align-items: flex-start;
    gap: 14px;
  }
  .qa-icon {
    width: 28px;
    height: 28px;
    border-radius: 8px;
    background: var(--primary-light);
    color: var(--primary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 13px;
    font-weight: 700;
    flex-shrink: 0;
    margin-top: 1px;
  }
  .qa-title {
    font-size: 15px;
    font-weight: 600;
    color: var(--text);
    line-height: 1.5;
    flex: 1;
  }
  .qa-badge {
    font-size: 11px;
    padding: 3px 10px;
    border-radius: 20px;
    font-weight: 500;
    flex-shrink: 0;
    margin-top: 2px;
  }
  .badge-hot { background: #FEF2F2; color: #DC2626; }
  .badge-new { background: #ECFDF5; color: #059669; }
  .badge-common { background: #F1F5F9; color: #64748B; }

  .qa-hover-hint {
    font-size: 12px;
    color: #94A3B8;
    margin-left: 42px;
    margin-top: 2px;
    opacity: 1;
    transition: opacity .2s;
  }
  .qa-card:hover .qa-hover-hint {
    opacity: 1;
  }

  /* 悬浮答案浮层 */
  .qa-answer-popup {
    position: absolute;
    left: 50%;
    transform: translateX(-50%) translateY(8px);
    background: var(--card-bg);
    border: 1px solid #C7D2FE;
    border-radius: 12px;
    padding: 20px 24px;
    width: calc(100% - 40px);
    max-width: 1000px;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transition: all .25s ease;
    z-index: 100;
    pointer-events: none;
  }
  .qa-answer-popup::before {
    content: '';
    position: absolute;
    top: -8px;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 0;
    border-left: 8px solid transparent;
    border-right: 8px solid transparent;
    border-bottom: 8px solid #C7D2FE;
  }
  .qa-answer-popup::after {
    content: '';
    position: absolute;
    top: -7px;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 0;
    border-left: 7px solid transparent;
    border-right: 7px solid transparent;
    border-bottom: 7px solid #fff;
  }

  .qa-card:hover .qa-answer-popup {
    opacity: 1;
    visibility: visible;
    transform: translateX(-50%) translateY(12px);
  }

  .answer-label {
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: .5px;
    color: var(--primary);
    margin-bottom: 10px;
  }
  .answer-text {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.8;
  }
  .answer-text ul {
    list-style: none;
    padding: 0;
  }
  .answer-text ul li {
    padding: 5px 0;
    padding-left: 16px;
    position: relative;
  }
  .answer-text ul li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 12px;
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--primary);
    opacity: .4;
  }

  .answer-footer {
    margin-top: 14px;
    padding-top: 12px;
    border-top: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 12px;
    color: #94A3B8;
  }
  .answer-tag {
    padding: 3px 8px;
    background: var(--primary-light);
    color: var(--primary);
    border-radius: 4px;
    font-size: 11px;
    font-weight: 500;
  }

  @media (max-width: 600px) {
    body { padding: 30px 12px; }
    .tab-btn { font-size: 12px; padding: 10px 8px; }
    .qa-card { padding: 16px 18px; }
    .qa-answer-popup { width: calc(100% - 20px); left: 10px; transform: translateY(8px); }
    .qa-card:hover .qa-answer-popup { transform: translateY(12px); }
  }