Pseudo-Classes & Selectors

:hover

selector or pseudo-class · 8 supported, 2 partial, 4 unsupported across 15 clients

The :hover pseudo-class applies styles when the user points at an element. It only works in clients that render <style> blocks, since inline styles cannot express pseudo-classes. Outlook on Windows ignores :hover entirely; most webmail clients honor it, with mobile clients being a no-op (no hover surface).

Client Support

Client	Category	Engine	Support
Gmail	webmail	Gmail Web	Supported
Gmail Android	mobile	Gmail Mobile	Partial
Gmail iOS	mobile	Gmail Mobile	Unsupported
Outlook 365	webmail	Outlook Web	Partial
Outlook (New)	desktop	Outlook Web	Unsupported
Outlook Classic	desktop	Microsoft Word	Unsupported
Outlook iOS	mobile	Outlook Mobile	Unsupported
Outlook Android	mobile	Outlook Mobile	Supported
Apple Mail	desktop	WebKit	Supported
Apple Mail iOS	mobile	WebKit	Supported
Yahoo Mail	webmail	Yahoo	Supported
Samsung Mail	mobile	Samsung	Supported
Thunderbird	desktop	Gecko	Supported
HEY Mail	webmail	WebKit	Supported
Superhuman	desktop	Blink	Unknown

Client-by-client behaviour for :hover

Fully supports :hover (8): Gmail, Outlook Android, Apple Mail, Apple Mail iOS, Yahoo Mail, Samsung Mail, Thunderbird, HEY Mail.

Partial support (2): Gmail Android, Outlook 365. Expect rendering quirks unique to each engine — partial support typically means a subset of values, an ignored shorthand, or sanitizer-specific rewrites.

No support (4): Gmail iOS, Outlook (New), Outlook Classic, Outlook iOS. Plan fallbacks for these clients before relying on :hover in production sends.

Behaviour unverified in: Superhuman.

When to use :hover in email

CTA button hover state on web-mode email previews.
Underline-on-hover styling for inline links in newsletter content.
Subtle background-color shifts on interactive cards in modern email designs.

Rendering behaviour and edge cases

Outlook on Windows strips <style> blocks and ignores :hover.
Gmail Web honors :hover when <style> blocks are preserved (which depends on sanitization rules).
Mobile clients have no hover surface — :hover is effectively a no-op.

Recommended fallback strategy

Treat :hover purely as enhancement. The base CTA must look complete and tappable without any hover state. Inline the static appearance and use <style> blocks only for the hover overlay.