body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: #f4f4f4;
    font-family: Arial, sans-serif;
}

.calculator {
    background: white;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 2px 2px 10px rgba(0, 0, 0, 0.2);
    text-align: center;
}

#display {
    width: 90%;
    height: 50px;
    font-size: 1.5rem;
    margin-bottom: 10px;
    text-align: right;
    padding: 10px;
}

.buttons {
    display: grid;
    grid-template-columns: repeat(4, 60px);
    gap: 10px;
}

button {
    padding: 15px;
    font-size: 1.2rem;
    cursor: pointer;
    border: none;
    background-color: #007BFF;
    color: white;
    border-radius: 5px;
}

button:hover {
    background-color: #0056b3;
}