The only option is to use images. You can do a lot in CSS these days but you don't know which mail client the recipient is using. If you spend time getting the styling to look good in a recent browser it might become totally unreadable if user is on some old mail client.
What you can easily do is simply put the cover as an image in the email template. (It won't have the shadow or highlight effect to make it stand out as 3D magazine)
You can find the URL if you use our oembed endpoint as described here:
As an example this oembed invocation:
Will return a lot of information about the publication. You’ll need to locate the ‘image.issuu’ link which in this case will return the following image thumbnail URL:
which can be inserted in MailChimp or any standard mail sender.