.welcome{
    margin: auto;
    background-color: lightgray;
    height: 30px;
    width: 300px;
    text-align: center;
    padding-top: 7px;
    border-radius: 10px;
}
.mainblock{
    padding-top: 0;
    margin: auto;
    margin-top: 30px;
    width: 500px;
    height: 500px;
    background-color: black;
    border-style: solid;
    border-color: black;
    border-radius: 20px;
}

.secondmainblock{
    margin: -19px 0 0 5px;
}

td{
    height:50px;
    width:50px;
    background: lightgray;
    border: 1px solid black;
    text-align: center;
    font-size: 40px;
}
.givenCell{
    background-color: yellow;/*rgba(255, 255, 255, 0.8);*/
    border: 1px solid rgba(0, 0, 0, 0.8);
    font-size: 40px;
    text-align: center;
    padding: 0;
}
table{
    margin-top: 24px;

    border-spacing: 0;
}
td:first-child{
    border-left: 2px solid black;
}

td:nth-child(3n){
    border-right: 2px solid black;
}
tr:first-child td{
    border-top: 2px solid black;

}
tr:nth-child(3n) td{
    border-bottom: 2px solid black;

}

.selectedCell{
    background: lime;
}

.redCell{
    background: red;
}
/*ambele clase*/
.givenCell.selectedCell {
    background: red;
}

/*elementele cu clasa2 care au parinte clasa1*/
.clasa1 > div.clasa2 {

}

tr:first-child td:first-child{
    border-top-left-radius: 16px;
}

tr:first-child td:last-child{
    border-top-right-radius: 16px;
}

tr:last-child td:first-child{
    border-bottom-left-radius: 16px;
}

tr:last-child td:last-child{
    border-bottom-right-radius: 16px;
}