body{
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background: linear-gradient(to right, rgb(85, 102, 9), rgb(172, 116, 33));
}


#calculator{
    font-family: Arial, sans-serif;
    background-color: hsl(224, 78%, 18%);
    border-radius: 15px;
    max-width: 500px;
    overflow: hidden;
}

#display{
    width: 100%;
    height: 100px;
    text-align: right;
    font-size: 5rem;
    padding: 25px;
    box-sizing: border-box;
}

#keys{
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
    padding: 25px;  
}

button{
     width: 100px;
     height: 100px;
     border-radius: 50px;
     border: none;
     background-color: hsl(51, 86%, 46%);
     color: white;
     font-size: 3rem;
     font-weight: bold;
     cursor: pointer;    
}

button:hover{
     background-color: hsl(49, 87%, 27%);
}

button:active{
    background-color: hsl(69, 70%, 36%);
}

.operator-btn{
    background-color: hsl(101, 94%, 46%);
}

.operator-btn:hover{
    background-color: hsl(96, 34%, 51%);
}