ID selector
The ID selector (#id) allows to apply styles to an element with the corresponding id attribute.
Outlook
Windows
2003
2007
2010
2013
2016
2019
Windows Mail
2019-10
macOS
2011
2016
Outlook.com
2019-10
iOS
2019-10
Android
2019-10
Samsung Email
Android
6.0
Mozilla Thunderbird
macOS
60.3
Fastmail
Desktop Webmail
2021-07
HEY
Desktop Webmail
2020-06
LaPoste.net
Desktop Webmail
2021-08
1&1
Desktop Webmail
2022-06
Android
2022-06
Mail.ru
Desktop Webmail
2020-10