body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    font-family: 'Arial', sans-serif;
    background-color: #F4EAE0;
}

.calculator {
    background-color: #000000;
    border-radius: 8px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    padding: 10px;
}

.display {
    padding: 70px 20px 16px 16px;
    text-align: right;
    font-size: 3em;
    color: #fff;
    background-color: #000000;
}

.keys {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
}

button {
    padding: 16px;
    margin: 5px;
    font-size: 1.5em;
    border: none;
    cursor: pointer;
    outline: none;
    border-radius: 50%;
    color: #fff;
    background-color: rgb(71, 71, 71);
}

.operator {
    background-color: #ff9500;
    color: #fff;
}

#zero {
    grid-column: span 2;
    text-align: left;
    padding-left: 25px;
    border-radius: 35%;
}

#clear,
#plusminus,
#percent {
    color: #000000;
    background-color: #9e9e9e;
}