Styling Templates

Use Only Inline CSS

When authoring templates in HTML, it is important to avoid using internal or external CSS style sheets, but to only use inline CSS to apply styles within the template content. This is because when templates are deployed to Outlook and OWA, or injected into emails by the Transport Agent, it is not possible to merge any CSS style sheet that may be present in an email with those in the template. This is also true when campaigns and disclaimers are appended to signatures.

In short, all styles within your HTML templates should be applied inline, for example:

<SPAN STYLE="font-family: arial; font-size: 10pt; color: black">Your text here</SPAN>

The best method to produce a clean template is to first complete the content of the template without any styles, and then apply the styles (such as bold, italic etc.) to the content as required. It is also recommended to avoid pasting into the HTML WYSIWYG editor from word processors, such as Microsoft Word, which may include a large amount of Word specific HTML tags and content, which can lead to formatting problems.

HTML and CSS Support in Outlook

Microsoft Outlook uses the HTML parsing and rendering engine from Microsoft Word to display HTML message bodies. The same HTML and CSS support available in Word is available in Outlook.

To learn about support for the HTML and CSS specifications provided by Word and Outlook please refer to the following Microsoft articles:

•Word 2007 HTML and CSS Rendering Capabilities in Outlook 2007 (Part 1 of 2)

•Word 2007 HTML and CSS Rendering Capabilities in Outlook 2007 (Part 2 of 2)

These articles provides reference documentation related to supported and unsupported HTML elements, attributes, and CSS properties.

Note that while the articles date back to 2006 and were written for Word 2007 and Outlook 2007, the content remains valid for Office 2013, 2016, 2019, 2021 and 365, and therefore remains valuable reference documentation when designing email signatures for the Outlook client.

More Information

Please refer to our Knowledge Base for more information on signature design.