Hotmail and line-height are not friends to the html email coder.
Apparently Hotmail adds a class and keeps line-height to default, even if you tried to define it in your style, in your table or your td.
To solve this problem which can drive you crazy, the only thing you have to do is insert the snippet below in the head of your html email template.
[pre lang=”css”]
.ExternalClass * {
Line-height: 100%;
}
[/pre]
You can then define the line-height without fear of breaking in the popular ESP.
If you have any other simpler hack for this, please share in the comments.