The margin attribute sets "as the name says" a distance beyond the previously set boundary. The defined edge will not have any color, in other words it will be transparent. The CSS margin properties are used to create space around boundary, outside of any defined borders.

With CSS, you have full control over the margins and you can add any value. There are properties for setting the margin for each side of an element (margin-top, margin-right, margin-bottom, and margin-left).

All the margin properties can have the next value:

• length - specifies a margin in px, pt, cm, etc. for top, bottom, left, right,
• % - specifies a margin in % of the width of the containing element for top, bottom, left, right,
• inherit - specifies that the CSS margin should be inherited from the parent element,

If the margin property has this four value:
margin: 12px 15px 12px 16px;
top margin is 12px
right margin is 15px
bottom margin is 12px
left margin is 16px

To shorten the code, it is possible to specify all the margin properties in one property.
The css margin property is a shorthand property for the following individual margin properties:
margin-top is 12px
margin-right is 15px
margin-bottom 12px
margin-left 16px

If the margin property has three values:
margin: 12px 15px 14px;
top margin is 12px
right and left margins are 15px
bottom margin is 14px

If the margin property has two values:
margin: 15px 20px;
top and bottom margin are 15px
right and left margin are 20px

If the margin property has one value:
margin: 16px;
all four margins are 16px

You can set the margin property to auto to horizontally center the element within its container.



CSS margin top, margin bottom, margin left, margin right, css margin 0 auto
CSS Margin, top, bottom, left, righ, auto - css tutorial