margin-left - CSS: Cascading Style Sheets 编辑

The margin-left CSS property sets the margin area on the left side of an element. A positive value places it farther from its neighbors, while a negative value places it closer.

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The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

The vertical margins of two adjacent boxes may fuse. This is called margin collapsing.

In the rare cases where width is overconstrained (i.e., when all of width, margin-left, border, padding, the content area, and margin-right are defined), margin-left is ignored, and will have the same calculated value as if the auto value was specified.

Syntax

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

/* Keyword values */
margin-left: auto;

/* Global values */
margin-left: inherit;
margin-left: initial;
margin-left: unset;

The margin-left property is specified as the keyword auto, or a <length>, or a <percentage>. Its value can be positive, zero, or negative.

Values

<length>

The size of the margin as a fixed value.

<percentage>

The size of the margin as a percentage, relative to the width of the containing block.

auto

The left margin receives a share of the unused horizontal space, as determined mainly by the layout mode that is used. If the values of margin-left and margin-right are both auto, the calculated space is evenly distributed. This table summarizes the different cases:

Value of display	Value of float	Value of position	Computed value of auto	Comment
inline, inline-block, inline-table	any	static or relative	0	Inline layout mode
block, inline, inline-block, block, table, inline-table, list-item, table-caption	any	static or relative	0, except if both margin-left and margin-right are set to auto. In this case, it is set to the value centering the element inside its parent.	Block layout mode
block, inline, inline-block, block, table, inline-table, list-item, table-caption	left or right	static or relative	0	Block layout mode (floating element)
any table-*, except table-caption	any	any	0	Internal table-* elements don't have margins, use border-spacing instead
any, except flex, inline-flex, or table-*	any	fixed or absolute	0, except if both margin-left and margin-right are set to auto. In this case, it is set to the value centering the border area inside the available width, if fixed.	Absolutely positioned layout mode
flex, inline-flex	any	any	0, except if there is any positive horizontal free space. In this case, it is evenly distributed to all horizontal auto margins.	Flexbox layout mode

Formal definition

Initial value	0
Applies to	all elements, except elements with table display types other than table-caption, table and inline-table. It also applies to ::first-letter and ::first-line.
Inherited	no
Percentages	refer to the width of the containing block
Computed value	the percentage as specified or the absolute length
Animation type	a length

Formal syntax

<length> | <percentage> | auto

Examples

Setting left margin using pixels and percentages

.content { margin-left: 5%; }
.sidebox { margin-left: 10px; }
.logo    { margin-left: -5px; }

Specifications

Specification	Status	Comment
CSS Basic Box Model The definition of 'margin-left' in that specification.	Working Draft	No significant change from CSS 2.1.
CSS Flexible Box Layout Module The definition of 'margin-left' in that specification.	Candidate Recommendation	Defines the behavior of margin-left on flex items.
CSS Level 2 (Revision 1) The definition of 'margin-left' in that specification.	Recommendation	Like in CSS1, but removes its effect on inline elements.
CSS Level 1 The definition of 'margin-left' in that specification.	Recommendation	Initial definition.

Browser compatibility

BCD tables only load in the browser

See also

• margin-top, margin-right, and margin-bottom and the margin shorthand
• The mapped logical properties: margin-block-start, margin-block-end, margin-inline-start, and margin-inline-end and the shorthands margin-block and margin-inline