1.css

body {
    font-family: Arial, sans-serif;
    background-color: #121212;
    color: #ffffff;
}

.calculator {
    width: 300px;
    margin: 100px auto;
    padding: 20px;
    border: 1px solid #444;
    border-radius: 5px;
    background-color: #1e1e1e;
}

#result {
    width: 100%;
    height: 50px;
    text-align: right;
    margin-bottom: 10px;
    font-size: 24px;
    background-color: #333;
    color: #ffffff;
    border: none;
    border-radius: 5px;
}

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

button {
    padding: 15px;
    font-size: 18px;
    cursor: pointer;
    background-color: #444;
    color: #ffffff;
    border: none;
    border-radius: 5px;
    transition: background-color 0.3s;
}

button:hover {
    background-color: #555;
}