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

.calculator {
    background-color: #fff;
    border-radius: 8px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    padding: 20px;
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
    max-width: 300px;
}

.display {
    grid-column: 1 / -1;
    background-color: #f9f9f9;
    padding: 10px;
    border-radius: 4px;
    font-size: 1.5rem;
    text-align: right;
}

button {
    background-color: #f0f0f0;
    border: none;
    padding: 15px;
    font-size: 1.2rem;
    border-radius: 4px;
    cursor: pointer;
}

.clear {
    grid-column: span 2;
    background-color: #ffcccc;
}

.equal {
    background-color: #80ff80;
}

.operator {
    background-color: #cceeff;
}