body {
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 80vh;
    background-color: hsl(0, 0%, 95%);
    padding: 100px;
    margin-top: 10px;
}

#Calculator {
    font-family: Arial, sans-serif;
    background-color: hsl(0, 0%, 15%);
    border-radius: 15px;
    max-width: 500px;
    overflow: hidden;
}

#display {
    width: 100%;
    padding: 20px;
    font-size: 3rem;
    text-align: left;
    border: none;
    background-color: hsl(0, 0%, 20%);
    color: white;
}

#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(0, 0%, 30%);
    color: white;
    font-size: 3rem;
    font-weight: bold;
    cursor: pointer;
}

button:hover {
    background-color: hsl(0, 0%, 40%);
}

/* button:active{
    background-color: hsl(0, 0%, 50%);
} */

.operator-btn {
    background-color: hsl(35, 100%, 55%);
}

.operator-btn:hover {
    background-color: hsl(35, 100%, 65%);
}

.operator-btn:active {
    background-color: hsl(35, 100%, 75%);
}

@media (max-width: 800px) {
    body {
        padding: 20px;
        margin-top: 100px;
    }
    #Calculator {
        max-width: 100%;
        border-radius: 0;
    }
    #keys {
        grid-template-columns: repeat(4, 1fr);
        gap: 5px;
        padding: 15px;
    }
    button {
        width: 70px;
        height: 70px;
        font-size: 2rem;
    }
}

@media (max-width: 400px) {
    button {
        width: 50px;
        height: 50px;
        font-size: 1.5rem;
    }
    #display {
        font-size: 2rem;
        padding: 10px;
    }
    @media (max-width: 260px) and (min-width: 232px) {
        body {
            padding: 10px;
            margin-top: 20px;
        }
        #Calculator {
            max-width: 100%;
            border-radius: 0;
        }
        #keys {
            grid-template-columns: repeat(4, 1fr);
            gap: 3px;
            padding: 10px;
        }
        button {
            width: 40px;
            height: 40px;
            font-size: 1.2rem;
        }
        #display {
            font-size: 1.5rem;
            padding: 5px;
        }
}
}