#tahvel{
    background-color: cyan;
    width: 30%;
    height: 30%;
    border: solid 2pt;
}
h1{
    background-color: violet;
    color: darkmagenta;
    border: solid 3pt deeppink;
    text-align: center;
}
input[type=button]{
    background-color: blue;
    color: white;
    padding: 10px 17px;
    border: 0;
}
input[type=button]:hover{
    background-color: lightskyblue;
}