CSS property · data last changed 10 Nov 2026
inset in email clients
Works in 3 of 21. Not supported in Gmail, Gmail Android, Gmail iOS and 12 more. Untested in HEY Mail, Fastmail and Superhuman.
Your reader in Outlook Classic sees the email without inset, even if it looks right where you tested it.
caniemail (MIT) via @emailens/engine 0.18.22
What to do instead in Outlook Classic
There is no drop-in fix for inset in Outlook Classic. Design so the email still reads without it.
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inset is not among the 24 features we have screenshotted on real installs. The ones we have →
All 21 clients, problems first
| Client | Support |
|---|---|
| Gmail | Not supported |
| Gmail Android | Not supported |
| Gmail iOS | Not supported |
| Outlook 365 | Not supported |
| Outlook (New) | Not supported |
| Outlook Classic | Not supported |
| Outlook iOS | Not supported |
| Outlook Android | Not supported |
| Outlook for Mac | Not supported |
| Yahoo Mail | Not supported |
| Yahoo Mail Android | Not supported |
| Yahoo Mail iOS | Not supported |
| Samsung Mail | Not supported |
| Proton Mail | Not supported See caveat 1 |
| AOL Mail | Not supported |
| HEY Mail | Untested |
| Fastmail | Untested |
| Superhuman | Untested |
| Apple Mail | Works |
| Apple Mail iOS | Works |
| Thunderbird | Works |
Caveats (1)
- 1. Proton Mail: Buggy. Almost all values are replaced by
unset.
Caveats as recorded by caniemail (MIT), one entry per wording.
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