I am trying to hide my preheader in Gmail and have tried all the tricks but its still visible. Any help would be great.

<body leftmargin="0" topmargin="0" marginwidth="0" marginheight="0" yahoo="fix" 
      style="font-family: 'Open Sans', Arial, sans-serif">
      <span class="preheader" style="display: none !important; visibility: hidden; opacity: 0; color: transparent; height: 0; width: 0; mso-hide: all; line=height: 0px; font-size: 0px; overflow: hidden; max-height: 0;">Test preheader</span>