body {
    font-family: 'Arial', sans-serif;
    background-color: #1d1f27;
    color: #fff;
    text-align: center;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}

.calculator {
    background-color: #2a2d3e;
    padding: 20px;
    border-radius: 15px;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.5);
}

.display {
    margin-bottom: 20px;
}

input {
    width: 100%;
    font-size: 2em;
    text-align: right;
    padding: 10px;
    border: none;
    background-color: #3a3e54;
    color: #fff;
    border-radius: 10px;
}

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

button {
    background-color: #4a4e6a;
    color: #fff;
    padding: 20px;
    font-size: 1.5em;
    border: none;
    border-radius: 10px;
    cursor: pointer;
}

button:hover {
    background-color: #63688b;
}

.saved-calculations {
    margin-top: 20px;
}

ul {
    list-style: none;
    padding: 0;
}