.contenedor{
    display:grid;
    grid-template-columns: 
    1fr 1fr 1fr 1fr;
    grid-gap: 2em;
    background-color: lightgray;
    padding: 10px;
}

.tarjeta{
    padding: 10px;
    background-color: white;
}

.tarjeta:hover{
    border: 2px solid; 
    border-color: darkgray;
}

.tarjeta img{
   width: 200px;
   height: 150px;
   margin: auto;
   display: block;
}