body {
    font-family: sans-serif;
}
th, td {
    border: 1px solid black;
    padding: 10px;
    width: 20px;
    transition: 0.7s;
}
tr:nth-child(1) {background-color: #d0d0d0;}
td:nth-child(1) {background-color: #d0d0d0;}
 
td:hover {
    background-color: rgb(228, 228, 228);
}
 
.tbl {
    border-collapse: collapse;
    text-align: center;
    margin: 10px;
}
 
.num_inp {
    width: 50px;
    height: 20px;
    text-align: left;
}
 
button {
    width: 80px;
    height: 30px;
    text-align: center;
    text-decoration: none;
    display: inline-block;
    border: none;
    border-radius: 3px;
    background-color: #d0d0d0;
    transition: 0.7s;
}
 
button:hover {
    background-color: #dedede;
}