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Does CSS :only-of-type Work in HTML Email?
Selects an element that is the only one of its type among siblings.
Quick Answer
Does :only-of-type work in HTML email?
The CSS :only-of-type property is supported in Outlook (Mac / Web), Apple Mail, Yahoo! Mail, Samsung Email, and others. It is NOT supported in Gmail, Outlook (Windows). Always include a safe fallback for unsupported clients.
Which Email Clients Support CSS :only-of-type?
CSS support for :only-of-type across email clients
| Email Client | Desktop | Mobile / Web | Notes |
|---|---|---|---|
| Gmail | ✗ No | ✗ No | — |
| Outlook (Windows) | ✗ No | ? | — |
| Outlook (Mac / Web) | ✓ Yes | ✓ Yes | — |
| Apple Mail | ✓ Yes | ✓ Yes | — |
| Yahoo! Mail | ✓ Yes | ✓ Yes | — |
| Samsung Email | ? | ✓ Yes | — |
| Thunderbird | ✓ Yes | ? | — |
| ProtonMail | ✗ No | ✓ Yes | — |
| Fastmail | ✓ Yes | ? | — |
Notes
- #1 Partial. Only supported on type selectors.
Frequently Asked Questions
Test Your Email Now
Paste your HTML and see how it renders in clients that don't support :only-of-type.
Building a new email instead of checking an existing one? MailViewr's Email Builder only lets you use CSS that's known to render across clients, so :only-of-type can't sneak into your markup by accident. Open the Email Builder →