#tdc-calculator {
    max-width: 500px;
    margin: auto;
    font-family: Arial, sans-serif;
}
#tdc-calculator label {
    display: block;
    margin-top: 10px;
}
#tdc-calculator input, #tdc-calculator select {
    width: 100%;
    padding: 8px;
    margin-top: 5px;
    box-sizing: border-box;
}
#tdc-calculator button {
    margin-top: 15px;
    padding: 10px;
    width: 100%;
    background-color: #0073aa;
    color: #fff;
    border: none;
    cursor: pointer;
}
#tdc-results {
    margin-top: 20px;
    padding: 10px;
    background: #f9f9f9;
    border-radius: 5px;
}