margin

This property is a shorthand for the following CSS properties:

• margin-top
• margin-right
• margin-bottom
• margin-left

/* Apply to all four sides */
margin: 1em;
margin: -3px;

/* top and bottom | left and right */
margin: 5% auto;

/* top | left and right | bottom */
margin: 1em auto 2em;

/* top | right | bottom | left */
margin: 2px 1em 0 auto;

/* Global values */
margin: inherit;
margin: initial;
margin: revert;
margin: revert-layer;
margin: unset;

The margin property may be specified using one, two, three, or four values. Each value is a <length>, a <percentage>, or the keyword auto. Negative values draw the element closer to its neighbors than it would be by default.

• When one value is specified, it applies the same margin to all four sides.
• When two values are specified, the first margin applies to the top and bottom, the second to the left and right.
• When three values are specified, the first margin applies to the top, the second to the right and left, the third to the bottom.
• When four values are specified, the margins apply to the top, right, bottom, and left in that order (clockwise).

<length>

The size of the margin as a fixed value.

<percentage>

The size of the margin as a percentage, relative to the inline size (width in a horizontal language, defined by writing-mode) of the containing block.

auto

The browser selects a suitable margin to use. For example, in certain cases this value can be used to center an element.

This property can be used to set a margin on all four sides of an element. Margins create extra space around an element, unlike padding, which creates extra space within an element.

The top and bottom margins have no effect on non-replaced inline elements, such as <span> or <code>.

You can horizontally center an element within its parent by setting margin: 0 auto;.

A more common method to center an element horizontally is by setting display: flex; and justify-content: center; on a container, which centers its flex item children.

Elements' top and bottom margins are sometimes collapsed into a single margin that is equal to the larger of the two margins. See Mastering margin collapsing for more information.

margin = 
  <'margin-top'>{1,4}  

<margin-top> = 
  <length-percentage>  |
  auto                 

<length-percentage> = 
  <length>      |
  <percentage>  

HTML

<div class="center">This element is centered.</div>

<div class="outside">This element is positioned outside of its container.</div>

CSS

.center {
  margin: auto;
  background: lime;
  width: 66%;
}

.outside {
  margin: 3rem 0 0 -3rem;
  background: cyan;
  width: 66%;
}

• Introduction to the CSS basic box model
• Margin collapsing
• margin-top, margin-right, margin-bottom, and margin-left
• 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