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Does CSS ::before Work in HTML Email?
Inserts generated content before an element's actual content using the content property.
Quick Answer
Does ::before work in HTML email?
The CSS ::before property is supported in Apple Mail, Samsung Email, Thunderbird, ProtonMail, and others. It is NOT supported in Gmail, Outlook (Windows), Yahoo! Mail. Always include a safe fallback for unsupported clients.
Which Email Clients Support CSS ::before?
CSS support for ::before across email clients
| Email Client | Desktop | Mobile / Web | Notes |
|---|---|---|---|
| Gmail | ✗ No | ✗ No | — |
| Outlook (Windows) | ✗ No | ? | — |
| Outlook (Mac / Web) | ~ Partial | ✗ No | — |
| Apple Mail | ✓ Yes | ✓ Yes | — |
| Yahoo! Mail | ✗ No | ✗ No | — |
| Samsung Email | ? | ✓ Yes | — |
| Thunderbird | ✓ Yes | ? | — |
| ProtonMail | ✗ No | ✓ Yes | — |
| Fastmail | ✓ Yes | ? | — |
Notes
- #1 Not supported with non Outlook accounts.
- #2 The pseudo-element is supported but the `content` property is not.
- #3 Partial. Only supported on type selectors.
Frequently Asked Questions
Related CSS Properties
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