.markdown-body h1 {
    font-size: 2rem !important;      /* 32px - 适中，不突兀 */
    line-height: 1.2;
    margin-bottom: 1.25rem;
    font-weight: 800;
}

.markdown-body h2 {
    font-size: 1.625rem !important;  /* 26px - 明显的二级区分 */
    border-bottom: 1px solid #eaecef;
    padding-bottom: 0.3rem;
    margin-top: 1.6rem;
    font-weight: 700;
}

.markdown-body h3 {
    font-size: 1.375rem !important;  /* 22px */
    font-weight: 600;
}

.markdown-body h4 {
    font-size: 1.1875rem !important; /* 19px */
    font-weight: 600;
}

.markdown-body h5 {
    font-size: 1.0625rem !important; /* 17px - 仅比正文大一点，靠字重区分 */
    font-weight: 600;
}

.markdown-body h6 {
    font-size: 1rem !important;      /* 16px - 与正文等大 */
    color: #6a737d;                  /* 依靠颜色变淡来体现它是最低级标题 */
    font-weight: 600;
}