table, td, th {
  border: 1px solid #ddd;
  }
  
  table {
  border-collapse: collapse;
  width: 100%;
}

th, td {
  border: 1px solid black;
  width: 400px;
  overflow: hidden;
  font-size: 12px;
  margin: 0;
  padding: 10px;
  border-bottom: 1px solid #ddd;
}

tr:hover {background-color: yellow;}