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This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The margin-block-start CSS property defines the logical block start margin of an element, which maps to a physical margin depending on the element's writing mode, directionality, and text orientation.

Syntax

/* <length> values */
margin-block-start: 10px;  /* An absolute length */
margin-block-start: 1em;   /* relative to the text size */
margin-block-start: 5%;    /* relative to the nearest block container's width */

/* Keyword values */
margin-block-start: auto;

/* Global values */
margin-block-start: inherit;
margin-block-start: initial;
margin-block-start: unset;

It corresponds to the margin-topmargin-rightmargin-bottom, or margin-left property depending on the values defined for writing-mode, direction, and text-orientation.

It relates to margin-block-end, margin-inline-start, and margin-inline-end, which define the other margins of the element.

Initial value0
Applies tosame as margin
Inheritedno
Percentagesdepends on layout model
Mediavisual
Computed valueif specified as a length, the corresponding absolute length; if specified as a percentage, the specified value; otherwise, auto
Animation typediscrete
Canonical orderthe unique non-ambiguous order defined by the formal grammar

Values

The margin-block-start property takes the same values as the margin-left property.

Formal syntax

<'margin-left'>

Example

HTML Content

<div>
  <p class="exampleText">Example text</p>
</div>

CSS Content

div {
  background-color: yellow;
  width: 120px;
  height: 120px;
}

.exampleText {
  writing-mode: vertical-lr;
  margin-block-start: 20px;
  background-color: #c8c800;
}

Specification

Specification Status Comment
CSS Logical Properties and Values Level 1
The definition of 'margin-block-start' in that specification.
Editor's Draft Initial definition

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Basic support
Experimental
Chrome Full support 69Edge No support NoFirefox Full support 41
Full support 41
No support 38 — 51
Disabled
Disabled From version 38 until version 51 (exclusive): this feature is behind the layout.css.vertical-text.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE No support NoOpera Full support 56Safari No support NoWebView Android Full support 69Chrome Android Full support 69Edge Mobile No support NoFirefox Android Full support 41
Full support 41
No support 38 — 51
Disabled
Disabled From version 38 until version 51 (exclusive): this feature is behind the layout.css.vertical-text.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android Full support 56Safari iOS No support NoSamsung Internet Android No support No

Legend

Full support  
Full support
No support  
No support
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
User must explicitly enable this feature.
User must explicitly enable this feature.

See also

ドキュメントのタグと貢献者

このページの貢献者: rachelandrew, fscholz, wbamberg, teoli, Sebastianz, kscarfone
最終更新者: rachelandrew,