I'm building a two-column hybrid email from a template in Dream Weaver. I've changed very little of the framework of the template, but it's completely breaking in the gmail app. Instead of stacking and filling the screen, the two columns stack but become much smaller and are centered on the screen. Any ideas why this might happen? It's working everywhere else that I've tested so far, both mobile and desktop. Code below with most of the actual content removed.

    <!doctype html>
<html style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;margin: 0 !important;padding: 0 !important;height: 100% !important;width: 100% !important;">
<head style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
<meta charset="utf-8" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
<!-- utf-8 works for most cases -->
<meta name="viewport" content="width=device-width" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
<!-- Forcing initial-scale shouldn't be necessary -->
<meta http-equiv="X-UA-Compatible" content="IE=edge" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
<!-- Use the latest (edge) version of IE rendering engine -->
<title style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">EmailTemplate-Hybrid</title>
<!-- The title tag shows in email notifications, like Android 4.4. -->

<!-- Please use an inliner tool to convert all CSS to inline as inpage or external CSS is removed by email clients -->
<!-- important in CSS is used to prevent the styles of currently inline CSS from overriding the ones mentioned in media queries when corresponding screen sizes are encountered -->

<!-- CSS Reset -->
<style type="text/css" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
/* What it does: Remove spaces around the email design added by some email clients. */
      /* Beware: It can remove the padding / margin and add a background color to the compose a reply window. */
html, body {
    margin: 0 !important;
    padding: 0 !important;
    height: 100% !important;
    width: 100% !important;
}
/* What it does: Stops email clients resizing small text. */
{
    -ms-text-size-adjust: 100%;
    -webkit-text-size-adjust: 100%;
}
/* What it does: Forces Outlook.com to display emails full width. */
.ExternalClass {
    width: 100%;
}
/* What is does: Centers email on Android 4.4 */
div[style*="margin: 16px 0"] {
    margin: 0 !important;
}
/* What it does: Stops Outlook from adding extra spacing to tables. */
table, td {
    mso-table-lspace: 0pt !important;
    mso-table-rspace: 0pt !important;
}
/* What it does: Fixes webkit padding issue. Fix for Yahoo mail table alignment bug. Applies table-layout to the first 2 tables then removes for anything nested deeper. */
table {
    border-spacing: 0 !important;
    border-collapse: collapse !important;
    table-layout: fixed !important;
    margin: 0 auto !important;
}
table table table {
    table-layout: auto;
}
/* What it does: Uses a better rendering method when resizing images in IE. */
img {
    -ms-interpolation-mode: bicubic;
}
/* What it does: Overrides styles added when Yahoo's auto-senses a link. */
.yshortcuts a {
    border-bottom: none !important;
}
/* What it does: Another work-around for iOS meddling in triggered links. */
a[x-apple-data-detectors] {
    color: inherit !important;
}
</style>

<!-- Progressive Enhancements -->
<style type="text/css" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
/* What it does: Hover styles for buttons */
/* What it does: Hover styles for buttons */
.button-td, .button-a {
    transition: all 100ms ease-in;
}
.button-td:hover, .button-a:hover {
    background: #4d104a !important;
    border-color: #4d104a !important;
}


/* Media Queries */
@media screen and (max-width: 515px) {
/* What it does: Forces elements to resize to the full width of their container. Useful for resizing images beyond their max-width. */
.fluid, .fluid-centered {
    width: 100% !important;
    max-width: 100% !important;
    height: auto !important;
    margin-left: auto !important;
    margin-right: auto !important;
}
/* And center justify these ones. */
.fluid-centered {
    margin-left: auto !important;
    margin-right: auto !important;
}
/* What it does: Forces table cells into full-width rows. */
.stack-column, .stack-column-center {
    display: block !important;
    width: 100% !important;
    max-width: 100% !important;
    direction: ltr !important;
}

}
/* What it does: Generic utility class for centering. Useful for images, buttons, and nested tables. */
.center-on-narrow {
    display: block !important;
    margin-left: auto !important;
    margin-right: auto !important;
    float: none !important;
}
table.center-on-narrow {
    display: inline-block !important;
}
}
</style>
</head>
<body width="100%" bgcolor="#78777a" style="margin: 0 !important;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;padding: 0 !important;height: 100% !important;width: 100% !important;" yahoo="yahoo">
<table cellpadding="0" cellspacing="0" border="0" height="100%" width="100%" bgcolor="#78777a" style="border-collapse: collapse;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;border-spacing: 0 !important;table-layout: fixed !important;margin: 0 auto !important;">
  <tr style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
    <td style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;"><center style="width: 100%;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">

        <!-- Visually Hidden Preheader Text : BEGIN -->
        <div style="display: none;font-size: 1px;line-height: 1px;max-height: 0px;max-width: 0px;opacity: 0;overflow: hidden;mso-hide: all;font-family: sans-serif;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;"> Find out how to qualify! </div>
        <!-- Visually Hidden Preheader Text : END -->

        <div style="max-width: 600px;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;"> 
          <!--[if (gte mso 9)|(IE)]>
            <table cellspacing="0" cellpadding="0" border="0" width="600" align="center">
            <tr>
            <td>
            <![endif]--> 

          <!-- Email Body : BEGIN -->
          <table cellspacing="0" cellpadding="0" border="0" align="center" bgcolor="#ffffff" width="100%" style="max-width: 600px;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;border-spacing: 0 !important;border-collapse: collapse !important;table-layout: fixed !important;margin: 0 auto !important;">

            <!-- Hero Image, Flush : BEGIN -->
            <tr style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
              <td class="full-width-image" align="center" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;"><img src="https://s3.amazonaws.com/production.campaign.talemetry/uploads/emails/images/9015/content_72923_C_REV_Altna_Tlmtry_Header.jpg" width="600" alt="alt_text" border="0" style="width: 100%;max-width: 600px;height: auto;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;-ms-interpolation-mode: bicubic;"></td>
            </tr>
            <!-- Hero Image, Flush : END --> 

            <!-- 1 Column Text : BEGIN -->
            <tr style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
              <td style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;"><table cellspacing="0" cellpadding="0" border="0" width="100%" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;table-layout: fixed !important;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;border-spacing: 0 !important;border-collapse: collapse !important;margin: 0 auto !important;">
                  <tr style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
                    <td style="padding: 20px 40px;text-align: left;font-family: sans-serif;font-size: 15px;mso-height-rule: exactly;line-height: 20px;color: #555555;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;"> <h1 style="color: #771b61;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;font-size: 28px;line-height: 32px;font-family: arial, sans-sarif;">
                    Text text text text

                    </td>
                  </tr>
                </table></td>
            </tr>
            <!-- 1 Column Text : END --> 

            <!-- Two Even Columns : BEGIN -->
            <tr style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
              <td bgcolor="#ffffff" align="center" height="100%" valign="top" width="100%" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;"><!--[if mso]>
                        <table border="0" cellspacing="0" cellpadding="0" align="center" width="580">
                        <tr>
                        <td align="center" valign="top" width="580">
                        <![endif]-->

                <table border="0" cellpadding="0" cellspacing="0" align="center" width="100%" style="max-width: 580px;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;table-layout: fixed !important;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;border-spacing: 0 !important;border-collapse: collapse !important;margin: 0 auto !important;">
                  <tr style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
                    <td align="center" valign="top" style="font-size: 0;padding: 10px 0;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;"><!--[if mso]>
                                    <table border="0" cellspacing="0" cellpadding="0" align="center" width="580">
                                    <tr>
                                    <td align="left" valign="top" width="330">
                                    <![endif]-->

                      <div style="display: inline-block;max-width: 50%;margin: 0 -2px;min-width: 200px;vertical-align: top;width: 100%;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;" class="stack-column">
                        <table cellspacing="0" cellpadding="0" border="0" width="100%" style="border-collapse: collapse;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;table-layout: fixed !important;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;border-spacing: 0 !important;margin: 0 auto !important;">
                          <tr style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
                            <td style="padding: 10px 10px;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;"><table cellspacing="0" cellpadding="0" border="0" width="100%" style="font-size: 14px;text-align: left;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;table-layout: fixed !important;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;border-spacing: 0 !important;border-collapse: collapse !important;margin: 0 auto !important;">
                                <tr style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
                                  <td style="background-color: #771b61;font-family: sans-serif;font-size: 20px;mso-height-rule: exactly;line-height: 20px;color: #ffffff;padding: 10px 0px 10px 15px;font-weight: bold;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;" class="stack-column-center">Heading</td>
                                </tr>
                                <tr style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
                                  <td style="font-family: sans-serif;font-size: 15px;mso-height-rule: exactly;line-height: 20px;color: #555555;padding-top: 10px;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;" class="stack-column-center"> text text text  </td>
                                </tr>
                              </table></td>
                          </tr>
                        </table>
                      </div>

                      <!--[if mso]>
                                    </td>
                                    <td align="left" valign="top" width="330">
                                    <![endif]-->

                      <div style="display: inline-block;max-width: 50%;margin: 0 -2px;min-width: 200px;vertical-align: top;width: 100%;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;" class="stack-column">
                        <table width="100%" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;table-layout: fixed !important;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;border-spacing: 0 !important;border-collapse: collapse !important;margin: 0 auto !important;">
                          <tr style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
                            <td style="padding: 10px 10px;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;"><table cellspacing="0" cellpadding="0" border="0" width="100%" style="font-size: 14px;text-align: left;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;table-layout: fixed !important;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;border-spacing: 0 !important;border-collapse: collapse !important;margin: 0 auto !important;">
                                <tr style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
                                  <td style="background-color: #771b61;font-family: sans-serif;font-size: 20px;mso-height-rule: exactly;line-height: 20px;color: #ffffff;padding: 10px 0px 10px 15px;font-weight: bold;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;" class="stack-column-center">Heading</td>
                                </tr>
                                <tr style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
                                  <td style="font-family: sans-serif;font-size: 15px;mso-height-rule: exactly;line-height: 20px;color: #555555;padding-top: 10px;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;" class="stack-column-center"> text text text </td>
                                </tr>
                              </table></td>
                          </tr>
                        </table>
                      </div>

                      <!--[if mso]>
                                    </td>
                                    </tr>
                                    </table>
                                    <![endif]--></td>
                  </tr>
                </table>

                <!--[if mso]>
                        </td>
                        </tr>
                        </table>
                        <![endif]--></td>
            </tr>
            <!-- Two Even Columns : END --> 
              <!-- 1 Column Text : BEGIN -->
            <tr style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
              <td style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;"><table cellspacing="0" cellpadding="0" border="0" width="100%" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;table-layout: fixed !important;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;border-spacing: 0 !important;border-collapse: collapse !important;margin: 0 auto !important;">
                  <tr style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
                    <td style="padding: 10px 40px 30px 40px;font-family: arial, sans-serif;mso-height-rule: exactly;line-height: 20px;color: #555555;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;">

                      <!-- Button : Begin -->

                      <table cellspacing="0" cellpadding="0" border="0" align="center" style="margin: auto;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;table-layout: fixed !important;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;border-spacing: 0 !important;border-collapse: collapse !important;">
                        <tr style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
                          <td style="border-radius: 4px;background: #771B61;text-align: center;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;transition: all 100ms ease-in;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;" class="button-td"><a href="http://careers.upmc.com/pages/nursing" style="background: #771B61;border: 15px solid #771B61;padding: 0 10px;color: #ffffff;font-family: sans-serif;font-size: 18px;line-height: 1.5;text-align: center;text-decoration: none;display: block;font-weight: bold;letter-spacing: 0.7px;border-radius: 4px;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;transition: all 100ms ease-in;" class="button-a"> 
                            <!--[if mso]>&nbsp;&nbsp;&nbsp;&nbsp;<![endif]-->APPLY NOW<!--[if mso]>&nbsp;&nbsp;&nbsp;&nbsp;<![endif]--> 
                            </a></td>
                        </tr>
                      </table>

                      <!-- Button : END --> 
                      </td>
                  </tr>
                </table></td>
            </tr>
            <!-- 1 Column Text : END --> 
              <!-- 1 Column Text : BEGIN -->
            <tr style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
              <td style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;"><table cellspacing="0" cellpadding="0" border="0" width="100%" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;table-layout: fixed !important;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;border-spacing: 0 !important;border-collapse: collapse !important;margin: 0 auto !important;">
                  <tr style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
                    <td style="background-color: #F3F3F3;padding: 20px 40px;text-align: left;font-family: arial, sans-serif;font-size: 16px;mso-height-rule: exactly;line-height: 20px;color: #555555;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;"> Text text text

                      </td>
                  </tr>
                </table></td>
            </tr>
            <!-- 1 Column Text : END --> 
                <!-- Footer Banner : BEGIN-->
               <tr style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
              <td class="full-width-image" align="center" padding="0" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;">
                  <a href="http://careers.upmc.com" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;color: #0092B3;text-decoration: none;font-weight: bold;"><img src="https://s3.amazonaws.com/production.campaign.talemetry/uploads/emails/images/9016/content_72923_C_REV_Footer.jpg" width="600" height="auto" alt="UPMC Center for Nursing Excellence" border="0" style="width: 100%;max-width: 600px;height: auto;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;-ms-interpolation-mode: bicubic;"></a>
                   </td>
            </tr>
              <!-- Footer Banner : END -->
          </table>
          <!-- Email Body : END --> 


          <!-- Email Footer : BEGIN -->
          <table cellspacing="0" cellpadding="0" border="0" align="center" width="100%" style="max-width: 600px;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;border-spacing: 0 !important;border-collapse: collapse !important;table-layout: fixed !important;margin: 0 auto !important;">
            <tr style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
              <td style="padding: 40px 10px;width: 100%;font-size: 12px;font-family: sans-serif;mso-height-rule: exactly;line-height: 18px;text-align: center;color: #DBD9D6;-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;mso-table-lspace: 0pt !important;mso-table-rspace: 0pt !important;">
                <a href="https://www.facebook.com/UPMCCareers" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;color: #0092B3;text-decoration: none;font-weight: bold;"><img alt="Facebook" width="30" height="30" src="https://s3.amazonaws.com/production.campaign.talemetry/uploads/emails/images/8849/content_iconmonstr-facebook-5-64.png" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;-ms-interpolation-mode: bicubic;"></a>
                  <a href="https://www.instagram.com/upmchealthbeat/?hl=en" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;color: #0092B3;text-decoration: none;font-weight: bold;"><img alt="Instagram" width="30" height="30" src="https://s3.amazonaws.com/production.campaign.talemetry/uploads/emails/images/8850/content_iconmonstr-instagram-10-64.png" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;-ms-interpolation-mode: bicubic;"></a>
                  <a href="https://www.linkedin.com/company/upmc/" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;color: #0092B3;text-decoration: none;font-weight: bold;"><img alt="LinkedIn" width="30" height="30" src="https://s3.amazonaws.com/production.campaign.talemetry/uploads/emails/images/8851/content_iconmonstr-linkedin-5-64.png" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;-ms-interpolation-mode: bicubic;"></a>
                  <a href="https://twitter.com/UPMCCareers" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;color: #0092B3;text-decoration: none;font-weight: bold;"><img alt="Twitter" width="30" height="30" src="https://s3.amazonaws.com/production.campaign.talemetry/uploads/emails/images/8852/content_iconmonstr-twitter-5-64.png" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;-ms-interpolation-mode: bicubic;"></a>
                  <a href="https://www.youtube.com/channel/UC2j6o6EbL-boXOC2kmntNng" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;color: #0092B3;text-decoration: none;font-weight: bold;"><img alt="YouTube" width="30" height="30" src="https://s3.amazonaws.com/production.campaign.talemetry/uploads/emails/images/8853/content_iconmonstr-video-15-64.png" style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;-ms-interpolation-mode: bicubic;"></a>
                  <br style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">

                  Company
                  <br style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
                  Address
                  <br style="-ms-text-size-adjust: 100%;-webkit-text-size-adjust: 100%;">
                  Address


                      </td>
            </tr>
          </table>
          <!-- Email Footer : END --> 
          <!--[if (gte mso 9)|(IE)]>
            </td>
            </tr>
            </table>
            <![endif]--> 
        </div>
      </center></td>
  </tr>
</table>
</body>
</html>