/* ===== 并排图片：同一行两张图自动并排 ===== */
#article-container p img:first-child:nth-last-child(2),
#article-container p img:first-child:nth-last-child(2) ~ img {
  display: inline-block;
  margin: 0 5px 20px;
  max-width: calc(50% - 15px);
}

/* ===== 并排图片：同一行三张图自动并排 ===== */
#article-container p img:first-child:nth-last-child(3),
#article-container p img:first-child:nth-last-child(3) ~ img {
  display: inline-block;
  margin: 0 4px 20px;
  max-width: calc(33.33% - 12px);
}