Font Sizes in Pixels (px)

The temptation will inevitably arise to use points or ems as the measurements for font sizes. Don’t do it! Stick with pixels. Everything inline and everything pixels.

<td align="left" valign="top" style="font-family:Helvetica, Arial, sans-serif; font-size:12px; mso-line-height-rule:exactly; line-height:20px; color:#58595b; padding:10px 20px 10px 20px;" bgcolor="#ffffff">Content</td>