body{
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: silver;
}
#calculator{
    font-family: Arial,sans-serif;
    background-color:  rgb(1, 1, 1);
    overflow: hidden;
    border-radius: 15px;
    max-width: 500px;
}
#display{
    width: 100%;
    padding: 15px;
    font-size: 5rem;
    border: none;
    background-color : rgb(32, 32, 32);
    color: white;

}
#keys{
    display: grid;
    grid-template-columns: repeat(4,1fr);
    padding: 25px;
    gap: 10px;
}
button{
    height: 100px;
    width: 100px;
    border-radius: 50px;
    border: none;
    background-color: rgb(32, 32, 37) ;
    color: white;
    font-weight: bold;  
    font-size: 3rem;
    cursor: pointer;
}

button:hover{
    background-color:  hsl(0, 0%, 55%);
}
button:active{
    background-color:   hsl(0, 0%, 65%);
}

.opreator-btn{
    background-color: hsl(39, 100%, 40%);

}
.opreator-btn:hover{
   background-color:  hsl(39, 100%, 65%);
}
.opreator-btn:active{
    background-color:  hsl(39, 100%, 45%);
}