body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: #f4f4f9;
    font-family: Arial, sans-serif;
    margin: 0;
}

.calculator {
    background-color: #333;
    padding: 20px;
    border-radius: 15px;
    box-shadow: 0px 5px 15px rgba(0, 0, 0, 0.3);
    width: 300px;
}

#display {
    width: 100%;
    height: 50px;
    font-size: 2rem;
    text-align: right;
    margin-bottom: 20px;
    padding: 10px;
    box-sizing: border-box;
    border: none;
    background-color: #fff;
    color: #333;
    border-radius: 5px;
}

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

button {
    height: 60px;
    font-size: 1.5rem;
    border: none;
    border-radius: 5px;
    background-color: #555;
    color: white;
    cursor: pointer;
    transition: background-color 0.2s;
}

button:hover {
    background-color: #777;
}

.operator {
    background-color: #ff9500;
}

.operator:hover {
    background-color: #cc7a00;
}

.clear {
    background-color: #ff3b30;
}

.clear:hover {
    background-color: #cc2e26;
}

.zero {
    grid-column: span 2; /* Le bouton 0 prend la largeur de deux colonnes */
}