table,td{
    border: 1px solid black;
    border-collapse: collapse;
    width: 500px; /*ESTA PROPIEDAD SOLO SE APLICA A LA TABLA*/
    height: 50px; /*ESTA PROPIEDAD SOLO SE APLICA A LA Tr*/
}
tr:nth-child(even)
td:nth-child(even),
tr:nth-child(odd)
td:nth-child(odd){
  background-color: #25a9bb;  
}

tr:nth-child(odd)
td:nth-child(even),
tr:nth-child(even)
td:nth-child(odd){
  background-color: #135c72;  
}