body {
    font-family: Arial, sans-serif;
    background-color: #f4f4f4;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}

.container {
    max-width: 400px;
    background: linear-gradient(to bottom right, #ffffff, #e7e7e7);
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
    text-align: center;
}

.calculator {
    margin-top: 20px;
}

#display {
    width: 100%;
    padding: 10px;
    border-radius: 5px;
    border: 1px solid #ccc;
    font-size: 24px;
    margin-bottom: 20px; /* Added margin to space from buttons */
}

.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
}

button {
    padding: 20px;
    border-radius: 5px;
    border: none;
    background-color: #007bff;
    color: white;
    font-size: 18px;
    cursor: pointer;
    transition: background-color 0.3s;
}

button:hover {
    background-color: #0056b3;
}
footer {
    margin-top: 20px;
    font-size: 14px;
}