img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* レスポンシブテーブルの指定 */
.responsive-table {
  width: 100%;
  border-collapse: collapse;
  border: 1px solid gray;
}
.responsive-table tr {
  border-top: 1px solid gray;
}

@media screen and (max-width: 600px) {
  /* スマホ表示の場合はヘッダ行を非表示にする */
  .responsive-table thead {
    display: none;
  }

  .responsive-table tr {
    display: block;
    margin-bottom: 1em;
  }

  .responsive-table th,
  .responsive-table td {
    display: block;
    width: 100%;
    padding: 6px 10px;
    box-sizing: border-box;
  }

  .responsive-table th {
    font-weight: bold;
    background-color: var(--table-header-bg, silver);
  }
}