Gmail显示HTML简报的边框

Question

我正在用HTML编写简报，GMAIL总是在下表中显示边框：

        <tr>
          <td align="center" bgcolor="#ffffff" style="padding: 20px 0 20px 0;margin:20px 0 20px 0;height:150px;">
            <table border="0" cellpadding="0" cellspacing="0" width="60%">
              <tr>
                <td align="center" style="padding: 20px 0 20px 0; color: #000000; font-family:Helvetica,verdana,sans-serif;border-top:5px solid;border-bottom:5px solid;solid;border-color:#000000;">
                    <span style="font-size:24px;padding: 0 0 0 0;color:#000000;"><b>THE MILAN DESIGN WEEK CONTINUES IN BRERA !</b></span>
                </td>                       
              </tr>
            </table>
          </td>
        </tr>
        <tr bgcolor="#ffffff">
          <td bgcolor="#ffffff" style="padding: 10px 20px 20px 20px;">
            <table border="0" cellpadding="0" cellspacing="0" width="100%">
              <tr>
                <td align="center">
                    <img src="DCW_RAW_1.jpg" alt="DCW éditions lampes Gras at Raw Brera" width="560" height="382" style="display: block;" />
                </td>                       
              </tr>
            </table>
          </td>
        </tr>

有人能解释我为什么吗？

这是代码的JSFiddle

JSFIDDLE

非常感谢！