margin-block-start

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. It corresponds to the margin-top, margin-right, margin-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 value	0
Applies to	same as margin
Inherited	no
Percentages	depends on layout model
Media	visual
Computed value	if specified as a length, the corresponding absolute length; if specified as a percentage, the specified value; otherwise, auto
Animation type	discrete
Canonical order	the unique non-ambiguous order defined by the formal grammar

Syntax

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

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 Level 1 The definition of 'margin-block-start' in that specification.	Editor's Draft	Initial definition

Browser compatibility

[1] Available since Gecko 38, but behind the preference layout.css.vertical-text.enabled, then disabled by default. The preference has been removed in Gecko 51 and this property cannot be disabled since this version.

See also

• The mapped physical properties: margin-top, margin-right, margin-bottom, and margin-left
• writing-mode, direction, text-orientation