@media screen and (max-width:767px) {
  /* data-label を表示 */
  .c-table__style2 tbody td:before {
    content: attr(data-label) !important;
  }
  
  /* data-labelが空の場合は非表示 */
  .c-table__style2 tbody td[data-label=""]:before,
  .c-table__style2 tbody td:not([data-label]):before {
    display: none !important;
  }
}