CSS property · data last changed 10 Nov 2026
flex-direction in email clients
Works in 12 of 21. Not supported in Gmail, Gmail Android, Gmail iOS and 6 more.
Your reader in Outlook Classic sees the email without flex-direction, even if it looks right where you tested it.
caniemail (MIT) via @emailens/engine 0.18.22
What to do instead in Outlook Classic
Avoid relying on flex-direction: column to stack columns on mobile. Instead, structure multi-column content as adjacent table cells with mobile media queries that set display: block !important and width: 100% !important on narrow screens, or use the hybrid inline-block approach that stacks automatically without requiring flexbox.
There is no drop-in fix for flex-direction in Outlook Classic. Design so the email still reads without it.
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flex-direction 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 Classic | Not supported |
| Outlook Android | Not supported |
| Yahoo Mail | Not supported |
| Yahoo Mail Android | Not supported |
| Yahoo Mail iOS | Not supported |
| AOL Mail | Not supported |
Works in 12: Outlook 365, Outlook (New), Outlook iOS and 9 more. Show all
| Client | Support |
|---|---|
| Outlook 365 | Works |
| Outlook (New) | Works |
| Outlook iOS | Works |
| Outlook for Mac | Works |
| Apple Mail | Works |
| Apple Mail iOS | Works |
| Samsung Mail | Works |
| Thunderbird | Works |
| HEY Mail | Works |
| Proton Mail | Works |
| Fastmail | Works |
| Superhuman | Works |
How flex-direction behaves
The flex-direction property establishes the main axis of a flex container, dictating whether flex items are laid out horizontally in rows or vertically in columns. While modern web layouts rely on flex-direction: column in media queries to adapt desktop rows for mobile screens, email sanitizers in Gmail and the legacy Word engine in Outlook Classic prevent flex-direction from working reliably across the broad email ecosystem.
- Gmail removes flex-direction declarations during HTML sanitization, preventing mobile media query overrides from switching rows to columns.
- Outlook Classic ignores all flex-direction values (row, column, row-reverse, column-reverse) because its Word engine predates CSS flexbox.
- Apple Mail (iOS and macOS) and modern webmail clients like Fastmail and Proton support flex-direction and responsive media query overrides.
Questions
Can I reverse column order in email using flex-direction: column-reverse?
Only in WebKit-based clients like Apple Mail. To reverse column order universally (including Gmail and Outlook), use the dir="rtl" table trick on the parent table and reset dir="ltr" on the child cells.
Does flex-direction work in Outlook Classic?
No. Microsoft Outlook 2016, 2019, 2021, and 365 on Windows do not support flex-direction or any other CSS flexbox properties.
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