CSS知识点-- Padding

The CSS padding properties define the space between the element border and the element content.

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Padding

The padding clears an area around the content (inside the border) of an element. The padding is affected by the background color of the element.

The top, right, bottom, and left padding can be changed independently using separate properties. A shorthand paddingproperty can also be used, to change all paddings at once.

Possible Values

Value	Description
length	Defines a fixed padding (in pixels, pt, em, etc.)
%	Defines a padding in % of the containing element

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Padding - Individual sides

In CSS, it is possible to specify different padding for different sides:

Example

p {
    padding-top: 25px;
    padding-right: 50px;
    padding-bottom: 25px;
    padding-left: 50px;
}

Padding - Shorthand property

To shorten the code, it is possible to specify all the padding properties in one property. This is called a shorthand property.

The shorthand property for all the padding properties is "padding":

Example

p {
    padding: 25px 50px;
}

The padding property can have from one to four values.

• padding: 25px 50px 75px 100px;
  • top padding is 25px
  • right padding is 50px
  • bottom padding is 75px
  • left padding is 100px
• padding: 25px 50px 75px;
  • top padding is 25px
  • right and left paddings are 50px
  • bottom padding is 75px
• padding: 25px 50px;
  • top and bottom paddings are 25px
  • right and left paddings are 50px
• padding: 25px;
  • all four paddings are 25px

http://www.w3schools.com/css/css_padding.asp