CSS Properties

gap

CSS property · 8 supported, 7 partial, 6 unsupported across 21 clients

Client Support

Client	Category	Engine	Support
Gmail	webmail	Gmail Web	Partial
Gmail Android	mobile	Gmail Mobile	Partial
Gmail iOS	mobile	Gmail Mobile	Partial
Outlook 365	webmail	Outlook Web	Partial
Outlook (New)	desktop	Outlook Web	Unsupported
Outlook Classic	desktop	Microsoft Word	Unsupported
Outlook iOS	mobile	Outlook Mobile	Partial
Outlook Android	mobile	Outlook Mobile	Partial
Outlook for Mac	desktop	WebKit	Supported
Apple Mail	desktop	WebKit	Supported
Apple Mail iOS	mobile	WebKit	Supported
Yahoo Mail	webmail	Yahoo	Unsupported
Yahoo Mail Android	mobile	Yahoo	Unsupported
Yahoo Mail iOS	mobile	Yahoo	Unsupported
Samsung Mail	mobile	Samsung	Supported
Thunderbird	desktop	Gecko	Supported
HEY Mail	webmail	WebKit	Supported
Proton Mail	webmail	Proton	Supported
AOL Mail	webmail	AOL	Unsupported
Fastmail	webmail	Fastmail	Partial
Superhuman	desktop	Blink	Supported

Client-by-client behaviour for gap

Fully supports gap (8): Outlook for Mac, Apple Mail, Apple Mail iOS, Samsung Mail, Thunderbird, HEY Mail, Proton Mail, Superhuman.

Partial support (7): Gmail, Gmail Android, Gmail iOS, Outlook 365, Outlook iOS, Outlook Android, Fastmail. Expect rendering quirks unique to each engine. Partial support typically means a subset of values, an ignored shorthand, or sanitizer-specific rewrites.

No support (6): Outlook (New), Outlook Classic, Yahoo Mail, Yahoo Mail Android, Yahoo Mail iOS, AOL Mail. Plan fallbacks for these clients before relying on gap in production sends.

Fixes & Workarounds

Outlook (New)

Unsupported

Use padding/margin on child elements instead of gap.

Before

<div style="display: flex; gap: 16px;">
  <div>Item 1</div>
  <div>Item 2</div>
  <div>Item 3</div>
</div>

After

<table role="presentation" cellpadding="0"
  cellspacing="0" border="0">
  <tr>
    <td style="padding-right: 16px;">Item 1</td>
    <td style="padding-right: 16px;">Item 2</td>
    <td>Item 3</td>
  </tr>
</table>

Use padding or margin on child elements instead of gap

Outlook Classic

Unsupported

Use cellpadding/cellspacing on tables, or padding on cells.

Before

<div style="display: flex; gap: 16px;">
  <div>Item 1</div>
  <div>Item 2</div>
  <div>Item 3</div>
</div>

After

<table role="presentation" cellpadding="0"
  cellspacing="0" border="0">
  <tr>
    <td style="padding-right: 16px;">Item 1</td>
    <td style="padding-right: 16px;">Item 2</td>
    <td>Item 3</td>
  </tr>
</table>

Use padding or margin on child elements instead of gap

Yahoo Mail

Unsupported

Use padding/margin on child elements instead of gap.

Before

<div style="display: flex; gap: 16px;">
  <div>Item 1</div>
  <div>Item 2</div>
  <div>Item 3</div>
</div>

After

<table role="presentation" cellpadding="0"
  cellspacing="0" border="0">
  <tr>
    <td style="padding-right: 16px;">Item 1</td>
    <td style="padding-right: 16px;">Item 2</td>
    <td>Item 3</td>
  </tr>
</table>

Use padding or margin on child elements instead of gap

Yahoo Mail Android

Unsupported

Use padding/margin on child elements instead of gap.

Before

<div style="display: flex; gap: 16px;">
  <div>Item 1</div>
  <div>Item 2</div>
  <div>Item 3</div>
</div>

After

<table role="presentation" cellpadding="0"
  cellspacing="0" border="0">
  <tr>
    <td style="padding-right: 16px;">Item 1</td>
    <td style="padding-right: 16px;">Item 2</td>
    <td>Item 3</td>
  </tr>
</table>

Use padding or margin on child elements instead of gap

Yahoo Mail iOS

Unsupported

Use padding/margin on child elements instead of gap.

Before

<div style="display: flex; gap: 16px;">
  <div>Item 1</div>
  <div>Item 2</div>
  <div>Item 3</div>
</div>

After

<table role="presentation" cellpadding="0"
  cellspacing="0" border="0">
  <tr>
    <td style="padding-right: 16px;">Item 1</td>
    <td style="padding-right: 16px;">Item 2</td>
    <td>Item 3</td>
  </tr>
</table>

Use padding or margin on child elements instead of gap

AOL Mail

Unsupported

Use padding/margin on child elements instead of gap.

Before

<div style="display: flex; gap: 16px;">
  <div>Item 1</div>
  <div>Item 2</div>
  <div>Item 3</div>
</div>

After

<table role="presentation" cellpadding="0"
  cellspacing="0" border="0">
  <tr>
    <td style="padding-right: 16px;">Item 1</td>
    <td style="padding-right: 16px;">Item 2</td>
    <td>Item 3</td>
  </tr>
</table>

Use padding or margin on child elements instead of gap

Gmail

Partial

Use padding/margin on child elements instead of gap.

Before

<div style="display: flex; gap: 16px;">
  <div>Item 1</div>
  <div>Item 2</div>
  <div>Item 3</div>
</div>

After

<table role="presentation" cellpadding="0"
  cellspacing="0" border="0">
  <tr>
    <td style="padding-right: 16px;">Item 1</td>
    <td style="padding-right: 16px;">Item 2</td>
    <td>Item 3</td>
  </tr>
</table>

Use padding or margin on child elements instead of gap

Gmail Android

Partial

Use padding/margin on child elements instead of gap.

Before

<div style="display: flex; gap: 16px;">
  <div>Item 1</div>
  <div>Item 2</div>
  <div>Item 3</div>
</div>

After

<table role="presentation" cellpadding="0"
  cellspacing="0" border="0">
  <tr>
    <td style="padding-right: 16px;">Item 1</td>
    <td style="padding-right: 16px;">Item 2</td>
    <td>Item 3</td>
  </tr>
</table>

Use padding or margin on child elements instead of gap

Gmail iOS

Partial

Use padding/margin on child elements instead of gap.

Before

<div style="display: flex; gap: 16px;">
  <div>Item 1</div>
  <div>Item 2</div>
  <div>Item 3</div>
</div>

After

<table role="presentation" cellpadding="0"
  cellspacing="0" border="0">
  <tr>
    <td style="padding-right: 16px;">Item 1</td>
    <td style="padding-right: 16px;">Item 2</td>
    <td>Item 3</td>
  </tr>
</table>

Use padding or margin on child elements instead of gap

Outlook 365

Partial

Use padding/margin on child elements instead of gap.

Before

<div style="display: flex; gap: 16px;">
  <div>Item 1</div>
  <div>Item 2</div>
  <div>Item 3</div>
</div>

After

<table role="presentation" cellpadding="0"
  cellspacing="0" border="0">
  <tr>
    <td style="padding-right: 16px;">Item 1</td>
    <td style="padding-right: 16px;">Item 2</td>
    <td>Item 3</td>
  </tr>
</table>

Use padding or margin on child elements instead of gap

Outlook iOS

Partial

Use padding/margin on child elements instead of gap.

Before

<div style="display: flex; gap: 16px;">
  <div>Item 1</div>
  <div>Item 2</div>
  <div>Item 3</div>
</div>

After

<table role="presentation" cellpadding="0"
  cellspacing="0" border="0">
  <tr>
    <td style="padding-right: 16px;">Item 1</td>
    <td style="padding-right: 16px;">Item 2</td>
    <td>Item 3</td>
  </tr>
</table>

Use padding or margin on child elements instead of gap

Outlook Android

Partial

Use padding/margin on child elements instead of gap.

Before

<div style="display: flex; gap: 16px;">
  <div>Item 1</div>
  <div>Item 2</div>
  <div>Item 3</div>
</div>

After

<table role="presentation" cellpadding="0"
  cellspacing="0" border="0">
  <tr>
    <td style="padding-right: 16px;">Item 1</td>
    <td style="padding-right: 16px;">Item 2</td>
    <td>Item 3</td>
  </tr>
</table>

Use padding or margin on child elements instead of gap

Fastmail

Partial

Use padding/margin on child elements instead of gap.

Before

<div style="display: flex; gap: 16px;">
  <div>Item 1</div>
  <div>Item 2</div>
  <div>Item 3</div>
</div>

After

<table role="presentation" cellpadding="0"
  cellspacing="0" border="0">
  <tr>
    <td style="padding-right: 16px;">Item 1</td>
    <td style="padding-right: 16px;">Item 2</td>
    <td>Item 3</td>
  </tr>
</table>

Use padding or margin on child elements instead of gap

Production guidance for gap

gap is a CSS property. Across the email client matrix, 8 of 15 tracked clients support it fully, 7 only partially, and 6 not at all. The clients most likely to require a workaround for this feature are Outlook (New), Outlook Classic, Yahoo Mail. Each of them needs a tailored fallback. See the per-client examples above for the specific code fix Emailens recommends.

When in doubt, ship a baseline that renders without gap and treat it as progressive enhancement on clients where support is verified. Emailens automatically detects cross-client divergence on this feature when you preview an email, so you can see exactly which template paths break before a campaign goes out.

Related Features

!important accent-color align-items animation aspect-ratio backdrop-filter background background-blend-mode

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Support data last updated Apr 27, 2026 · synced from caniemail.com via @emailens/engine.