.single_post {
    width: 100%;
    margin: 0 auto;
    padding: 40px 0;
  }
  
  .post_detail {
    max-width: 700px;
    margin: 0 auto;
  }
  
  .post_thumbnail {
    width: 100%;
    height: 576px;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #f9f9f9; /* 背景色があると画像外の余白も見やすい */
    overflow: hidden;
  }
  
  .post_thumbnail img {
    max-width: 100%;
    max-height: 100%;
    height: auto;
    width: auto;
    object-fit: contain;
    display: block;
  }
  
  .post_title {
    font-size: 2rem;
    margin-bottom: 20px;
  }
  
  .post_meta {
    font-size: 0.9rem;
    color: #666;
    margin-bottom: 20px;
  }
  
  .post_content {
    font-size: 1rem;
    line-height: 1.8;
  }