* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

.calculator {
    background-color: #fff;
    border-radius: 10px;
    padding: 20px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

#display {
    width: 100%;
    height: 50px;
    font-size: 2em;
    text-align: right;
    padding: 10px;
    margin-bottom: 20px;
    border: 2px solid #ccc;
    border-radius: 5px;
    background-color: #f1f1f1;
}

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

button {
    font-size: 1.5em;
    padding: 20px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

button:hover {
    background-color: #f0f0f0;
}

button.operator {
    background-color: #ff9800;
    color: white;
}

button.operator:hover {
    background-color: #f57c00;
}

button.clear {
    background-color: #e91e63;
    color: white;
}

button.clear:hover {
    background-color: #d81b60;
}