Pseudo-Classes & Selectors

pseudo-class-active

CSS property · 9 supported, 2 partial, 9 unsupported across 21 clients

9 of 21 email clients render pseudo-class-active fully (Sep 2, 2026 data); it breaks outright in Gmail, Gmail Android, Gmail iOS and 6 more.

4/7 webmail, 2/6 desktop, 3/8 mobile clients support pseudo-class-active fully.
Unsupported in Gmail, Gmail Android, Gmail iOS, Outlook (New) and 5 more.
Partial in Outlook 365, Apple Mail, behavior differs from browsers, test before relying on it.
Outlook Classic (Word engine, supported to at least 2029) does not fully support pseudo-class-active, and its replacement changes little here; see the deprecation diff.
Across all clients, only 6 of 298 tracked HTML/CSS features render identically everywhere.

Source: caniemail.com (MIT), via the Emailens engine. Last tested upstream Oct 28, 2019, synced by Emailens Sep 2, 2026.

Client Support

Client	Category	Engine	Support
Gmail	webmail	Gmail Web	Unsupported
Gmail Android	mobile	Gmail Mobile	Unsupported
Gmail iOS	mobile	Gmail Mobile	Unsupported
Outlook 365	webmail	Outlook Web	Partial^{See caveat 1}
Outlook (New)	desktop	Outlook Web	Unsupported
Outlook Classic	desktop	Microsoft Word	Unsupported
Outlook iOS	mobile	Outlook Mobile	Unsupported
Outlook Android	mobile	Outlook Mobile	Supported
Outlook for Mac	desktop	WebKit	Supported
Apple Mail	desktop	WebKit	Partial^{See caveat 2}
Apple Mail iOS	mobile	WebKit	Unsupported
Yahoo Mail	webmail	Yahoo	Supported
Yahoo Mail Android	mobile	Yahoo	Supported
Yahoo Mail iOS	mobile	Yahoo	Supported
Samsung Mail	mobile	Samsung	Unsupported
Thunderbird	desktop	Gecko	Supported
HEY Mail	webmail	WebKit	Supported
Proton Mail	webmail	Proton	Supported
AOL Mail	webmail	AOL	Unsupported
Fastmail	webmail	Fastmail	Supported
Superhuman	desktop	Blink	Unknown

Documented caveats (2)

1.Outlook 365: Partial. Only supported on type selectors.
2.Apple Mail: Partial. Supported with mouse clicks. Not supported with keyboard input.

Caveats recorded by caniemail.com (MIT) and carried verbatim, one entry per wording rather than per client.

Client-by-client behaviour for pseudo-class-active

Fully supports pseudo-class-active (9): Outlook Android, Outlook for Mac, Yahoo Mail, Yahoo Mail Android, Yahoo Mail iOS, Thunderbird, HEY Mail, Proton Mail, Fastmail.

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

No support (9): Gmail, Gmail Android, Gmail iOS, Outlook (New), Outlook Classic, Outlook iOS, Apple Mail iOS, Samsung Mail, AOL Mail. Plan fallbacks for these clients before relying on pseudo-class-active in production sends.

Behaviour unverified in: Superhuman.