.serainne-about-section {
    --sa-charcoal: #333333;
    --sa-navy: #1e3a6f;
    --sa-light-gray: #e8e6e4;
    --sa-text-light: #ffffff;
    --sa-text-dark: #1a1a1a;
    --sa-text-muted: #555555;
    --sa-accent: #1e3a6f;

    width: 100%;
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
  }

  .serainne-about-section *,
  .serainne-about-section *::before,
  .serainne-about-section *::after {
    box-sizing: border-box;
  }

  /* 顶部深灰区块 */
  .serainne-about-hero {
    background-color: var(--sa-charcoal);
    color: var(--sa-text-light);
    text-align: center;
    padding: 80px 20px;
  }

  .serainne-about-hero h2 {
    margin: 0 0 20px 0;
    font-size: 40px;
    font-weight: 700;
    color: var(--sa-text-light);
  }

  .serainne-about-hero p {
    margin: 0 auto;
    max-width: 900px;
    font-size: 17px;
    color: var(--sa-text-light);
  }

  /* 中间两栏：stretch 让左右等高 */
  .serainne-about-row {
    display: flex;
    flex-wrap: wrap;
    align-items: stretch;
    width: 100%;
    margin: 0;
  }

  .serainne-about-col {
    flex: 1 1 50%;
    padding: 60px 50px;
    min-width: 320px;
  }

  /* 左栏作为纵向 flex，按钮置底以保持等高 */
  .serainne-about-col.light {
    background-color: var(--sa-light-gray);
    color: var(--sa-text-dark);
    display: flex;
    flex-direction: column;
  }

  .serainne-about-col.dark {
    background-color: var(--sa-navy);
    color: var(--sa-text-light);
  }

  .serainne-about-col h3 {
    margin: 0 0 12px 0;
    font-size: 22px;
    font-weight: 700;
    line-height: 1.4;
  }

  .serainne-about-col .subtitle {
    margin: 0 0 16px 0;
    font-size: 15px;
    font-weight: 600;
    color: var(--sa-navy);
  }

  .serainne-about-col h4 {
    margin: 28px 0 14px 0;
    font-size: 15px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.5px;
  }

  .serainne-about-col p {
    margin: 0 0 16px 0;
    font-size: 15px;
    color: inherit;
  }

  .serainne-about-col .lead {
    font-size: 16px;
    margin-bottom: 8px;
  }

  .serainne-about-col .closing {
    margin: 18px 0 0 0;
    font-size: 15px;
  }

  /* 左侧勾选列表 */
  .serainne-checklist {
    margin: 0;
    padding: 0;
    list-style: none;
  }

  .serainne-checklist li {
    position: relative;
    padding-left: 24px;
    margin-bottom: 12px;
    font-size: 15px;
    line-height: 1.5;
  }

  .serainne-checklist li::before {
    content: "✔";
    position: absolute;
    left: 0;
    top: 0;
    color: var(--sa-accent);
    font-weight: 700;
  }

  /* 左栏按钮（置底） */
  .serainne-cta {
    margin-top: auto;
    padding-top: 28px;
  }

  .serainne-btn {
    display: inline-block;
    background-color: var(--sa-navy);
    color: var(--sa-text-light);
    text-decoration: none;
    font-size: 15px;
    font-weight: 700;
    padding: 14px 32px;
    border-radius: 4px;
    transition: background-color 0.2s ease;
  }

  .serainne-btn:hover {
    background-color: #16305a;
  }

  /* 右侧编号列表 */
  .serainne-numbered-list {
    margin: 24px 0 0 0;
    padding: 0;
    list-style: none;
  }

  .serainne-numbered-list li {
    margin-bottom: 24px;
  }

  .serainne-numbered-list .item-title {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 8px;
  }

  .serainne-numbered-list .item-title .num {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background-color: var(--sa-text-light);
    color: var(--sa-navy);
    font-size: 13px;
    font-weight: 700;
    flex-shrink: 0;
  }

  .serainne-numbered-list p {
    margin: 0 0 8px 34px;
    font-size: 15px;
  }

  .serainne-numbered-list .sub-list {
    margin: 0 0 0 34px;
    padding: 0;
    list-style: none;
  }

  .serainne-numbered-list .sub-list li {
    position: relative;
    padding-left: 14px;
    margin-bottom: 4px;
    font-size: 15px;
  }

  .serainne-numbered-list .sub-list li::before {
    content: "•";
    position: absolute;
    left: 0;
    top: 0;
  }

  /* 移动端适配 */
  @media (max-width: 768px) {
    .serainne-about-hero {
      padding: 50px 20px;
    }

    .serainne-about-hero h2 {
      font-size: 28px;
    }

    .serainne-about-hero p {
      font-size: 15px;
    }

    .serainne-about-col {
      flex: 1 1 100%;
      padding: 40px 24px;
      min-width: auto;
    }

    .serainne-about-col h3 {
      font-size: 20px;
    }

    .serainne-about-col .subtitle {
      font-size: 14px;
    }

    .serainne-about-col h4 {
      font-size: 14px;
    }

    .serainne-about-col p,
    .serainne-about-col .lead,
    .serainne-about-col .closing,
    .serainne-checklist li,
    .serainne-numbered-list p,
    .serainne-numbered-list .sub-list li {
      font-size: 14px;
    }

    .serainne-cta {
      padding-top: 24px;
    }

    .serainne-btn {
      display: block;
      text-align: center;
      padding: 14px 20px;
    }
  }