AMP

Supported CSS

AMP for Email specifies additional CSS constraints which are described in AMP for Email Supported CSS.

Like all web pages, AMP pages are styled with CSS, but you can’t reference external

stylesheets.

Also certain styles are disallowed due to performance implications.

Styles may live in the head of the document or as inline style attributes (see Add styles to a page). But you can use CSS preprocessors and templating to build static pages to better manage your content.

NOTE – AMP components come with default styles to make authoring responsive pages reasonably easy. These styles are defined in the amp.css.

Disallowed styles

The following styles aren’t allowed in AMP pages:

Banned style Description
!important qualifier Use and reference to !important is not allowed. This is a necessary requirement to enable AMP to enforce its element sizing rules.
<link rel=”stylesheet”> Disallowed.
i-amphtml- class and i-amphtml- tag names. The validator disallows class and tags names with the following regex `(^|\W)i-amphtml-`. These are reserved for internal use by the AMP framework. It follows, that the user's stylesheet may not reference CSS selectors for i-amphtml- classes and tags.

Performance recommendations

These allowed styles should restrict values to the following for an optimal performance:

Restricted style Description
transition property Only GPU-accelerated properties (currently opacity, transform and -vendorPrefix-transform).