#leistungsrechner {
    max-width: 300px;
    padding: 15px;
    border: 1px solid #ccc;
    border-radius: 8px;
    font-family: sans-serif;
    background: #2b2b2b;
    color: #fff;
}

#leistungsrechner input {
    width: 100%;
    margin-bottom: 10px;
    padding: 6px;
    box-sizing: border-box;
    background: #444;
    color: #fff;
    border: 1px solid #666;
}

#leistungsrechner button {
    width: 100%;
    padding: 8px;
    background: #0078d4;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
}

#leistungsrechner button:hover {
    background: #005fa3;
}