<details>
    <summary class="dropdown">
    Useful
    </summary>
    <table border="2px solid black" cellspacing="0px" cellpadding="2px">
        <caption align="top">
        Refer it!</caption>
        <tr>
        <th>Name</th>
        <th>Type</th>
        <th>Information</th>
        </tr>
        <tr>
        <td>
        <a href="www.google.com">Google</a>
        </td>
        <td>
        Search Engine, Every kind of developer
        </td>
        <td>
        -
        </td>
        </tr>
    </table>
    </details>