ch unit
Support for ch unit, relative to the width of a ‘0’.
Outlook
Windows
2003
2007
2010
2013
2016
2019
Windows Mail
2020-02
macOS
2016
Outlook.com
2020-02
iOS
2020-02
Android
2020-02
Samsung Email
Android
9.0
Fastmail
Desktop Webmail
2021-07
HEY
Desktop Webmail
2020-06
LaPoste.net
Desktop Webmail
2021-08
1&1
Desktop Webmail
2022-08
Android
2022-08
Mail.ru
Desktop Webmail
2020-10