body {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100vh;
    margin: 0;
    background-color: rgb(80, 80, 80);
}

.calculator {
    border: 2px solid #333;
    border-radius: 10px;
    overflow: hidden;
    width: 300px;
    background-color: rgb(35, 35, 35);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.display {
    color: rgb(199, 199, 199);
    padding: 10px;
    text-align: right;
    font-size: 1.5em;
    border-bottom: 2px solid #333;
}

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

button {
    padding: 15px;
    font-size: 1em;
    border: none;
    outline: none;
    cursor: pointer;
    background-color: #4CAF50;
    color: white;
}

button:hover {
    background-color: #45a049;
}