Our corporate typeface is Source Sans Pro. We use four weights: light (h1 only), regular, semibold and occasionally bold.
Web fonts are not universally supported across email clients and it is important to specify a fallback web safe font. We use Helvetica, Arial or a sans-serif font as our default fallbacks.
More documentation on typography and the use of web fonts in email can be found on Litmus.
The full body of the email should be no more than 640px wide. To ensure maximum readability, paragraph text should be set at an ideal line length of 45-80 characters per line (CPL). This translates to body copy set within a 300-500px wide area on a large-screen device. Lines of text that are much longer or shorter can become difficult for users to read – especially with paragraphs or multiple lines of text.
There are six primary types of headings available through the standard header HTML tags. Heading elements identify important sections of content and create a logical, informational hierarchy for your message. It is important to remain consistent in the usage of headers throughout the body of the email.
Body Copy and Smaller Styles
Body copy should be identified by using the paragraph <p> style.
Small text is used for supporting text, such as captions and other secondary copy. It should not be used as the primary body copy size.
Smaller text should be used only for disclaimers or short amounts of copy.
Four weights can be applied to Source Sans Pro by using the following inline CSS styles:
Links in copy blocks are underlined. Link elements sit away from blocks of copy and are identified by using a right arrow HTML entity.
It is important to use meaningful link text that provides adequate context to let subscribers know where the link is taking them.