table{
  border-collapse: collapse;
  width : 100%;
}
table th,
table td{
  padding: 10px;
  border: 1px solid #999;
}
table th{
  background-color: #eee;
  text-align: center;
  width: 30%;
}

@media screen and (max-width: 400px) {
  table{
    border-top: 1px solid #999;
  }
  table td{
    display: block;
    text-align: center;
  }
  table th{
    display: block;
    border-top: none;
    border-bottom: none;
    width: 100%;
  }
}