styles.css

body {
    font-family: Arial, sans-serif;
    background-color: #113946;
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
}

.calculator {
    background: #fff;
    border-radius: 10px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
    padding: 20px;
    width: 300px;
    text-align: center;
}

input#display {
    width: 290px;
    height: 50px;
    margin-bottom: 10px;
    font-size: 18px;
    text-align: right;
    border: 2px solid #ddd;
    border-radius: 5px;
    padding: 5px;
}

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

button {
    font-size: 18px;
    padding: 15px;
    background: #f7f9fc;
    border: 1px solid #ddd;
    border-radius: 5px;
    cursor: pointer;
    transition: all 0.2s;
}

button:hover {
    background: #e9ecef;
}

.history {
    margin-top: 20px;
    text-align: left;
}

.history h2 {
    font-size: 16px;
}

.history ul {
    list-style-type: none;
    padding: 0;
    font-size: 14px;
    max-height: 100px;
    overflow-y: auto;
    border: 1px solid #ddd;
    padding: 10px;
    background: #f7f9fc;
}