table{
    border-collapse: collapse;
}

th,td{
    border: 3px solid blue;
    width: 45px;
    text-align: center;
    transition: 0.5s;
}

td:hover{background-color: cadetblue;
}

.not_current{
    opacity: 0.4;
}

#current_day{background-color: blue;
color: white;
}

#merging_cells_table td{
    width: 100px;
    height: 100px;
    font-size: 50px;
    font-weight: bold;
}