.calculator {
    font-family: Arial, Helvetica, sans-serif;
    background-color: rgb(29, 29, 29);
    border-radius: 10px;
    max-width: 500px;
    overflow: hidden;
    margin: 5px; 
}

.keys {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(80px, 1fr)); 
    gap: 10px;
    padding: 25px;
}

button {
    width: 90%;
    height: 70px; 
    border-radius: 15px; 
    border: none;
    background-color: rgb(68, 68, 68);
    color: white;
    font-size: 2rem; 
    font-weight: bold;
    cursor: pointer;
}

.operator-btn {
    background-color: orange;
    grid-column: span 2; 
}

#display {
    width: 100%;
    padding: 30px;
    font-size: 3rem; 
    text-align: left;
    border: none;
    background-color: rgb(63, 63, 63);
    color: white;
}

body {
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: rgb(209, 209, 209);
}


@media (max-width: 500px) {
    .calculator {
        max-width: 100%; 
    }

    #display {
        font-size: 4rem; 
    }

    .operator-btn {
        grid-column: 4; 
    }
}