body {
    font-family: 'Times New Roman', Times, serif;
    background-color: aliceblue;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}

.calculator {
    background-color: #f4f4f4;
    border-radius: 15px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
    padding: 20px;
    width: 320px;
}

.display {
    background-color: #fff;
    border-radius: 10px;
    padding: 15px;
    font-size: 1.5rem;
    text-align: right;
    border: 1px solid #ccc;
    margin-bottom: 15px;
    overflow-x: auto;
    min-height: 40px;
}

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

button {
    padding: 15px;
    font-size: 1.2rem;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    background-color: #e0e0e0;
    transition: background-color 0.2s ease, transform 0.1s ease;
}

button:hover {
    background-color: chartreuse;
    transform: scale(1.05);
}

button:active {
    transform: scale(0.98);
}

button.operator {
    background-color: #ffb84d;
}

button.equal {
    background-color: #4CAF50;
    color: white;
    grid-column: span 2; /* Make '=' button larger */
}

button.clear {
    background-color: #f44336;
    color: white;
}