tablas.css

table,td,th{
    text-align: center;
    border: 1px solid black;
    border-collapse: collapse;
}

caption{
    font-weight:bold;
}

td,th{
    padding: 10px;
}

th{
    background: lightgreen;
}

.uno{
    background-color: cornflowerblue;
}

.dos{
    background-color: darkcyan;
}

#horas{
    background-color: coral;
    vertical-align: center;
}