我可以只为填充添加背景色吗？

You can't set colour of the padding.

You will have to create a wrapper element with the desired background colour. Add border to this element and set it's padding.

Look here for an example: http://jsbin.com/abanek/1/edit

I'd just wrap the header with another div and play with borders.

<div class="header-border"><div class="header-real">


<p>Foo</p>


</div></div>

CSS:

.header-border { border: 2px solid #000000; }
.header-real { border: 10px solid #003399; background: #cccccc; padding: 10px; }

There is no exact functionality to do this.

Without wrapping another element inside, you could replace the border by a box-shadow and the padding by the border. But remember the box-shadow does not add to the dimensions of the element.

jsfiddle is being really slow, otherwise I'd add an example.

You can use background-gradients for that effect. For your example just add the following lines (it is just so much code because you have to use vendor-prefixes):

background-image:
-moz-linear-gradient(top, #000 10px, transparent 10px),
-moz-linear-gradient(bottom, #000 10px, transparent 10px),
-moz-linear-gradient(left, #000 10px, transparent 10px),
-moz-linear-gradient(right, #000 10px, transparent 10px);
background-image:
-o-linear-gradient(top, #000 10px, transparent 10px),
-o-linear-gradient(bottom, #000 10px, transparent 10px),
-o-linear-gradient(left, #000 10px, transparent 10px),
-o-linear-gradient(right, #000 10px, transparent 10px);
background-image:
-webkit-linear-gradient(top, #000 10px, transparent 10px),
-webkit-linear-gradient(bottom, #000 10px, transparent 10px),
-webkit-linear-gradient(left, #000 10px, transparent 10px),
-webkit-linear-gradient(right, #000 10px, transparent 10px);
background-image:
linear-gradient(top, #000 10px, transparent 10px),
linear-gradient(bottom, #000 10px, transparent 10px),
linear-gradient(left, #000 10px, transparent 10px),
linear-gradient(right, #000 10px, transparent 10px);

No need for unecessary markup.

If you just want to have a double border you could use outline and border instead of border and padding.

While you could also use pseudo-elements to achieve the desired effect, I would advise against it. Pseudo-elements are a very mighty tool CSS provides, if you "waste" them on stuff like this, you are probably gonna miss them somewhere else.

I only use pseudo-elements if there is no other way. Not because they are bad, quite the opposite, because I don't want to waste my Joker.

Another option with pure CSS would be something like this:

nav {
margin: 0px auto;
width: 100%;
height: 50px;
background-color: white;
float: left;
padding: 10px;
border: 2px solid red;
position: relative;
z-index: 10;
}


nav:after {
background-color: grey;
content: '';
display: block;
position: absolute;
top: 10px;
left: 10px;
right: 10px;
bottom: 10px;
z-index: -1;
}

<nav>Some text or anything</nav>

Demo here

This would be a proper CSS solution which works for IE8/9 as well (IE8 with html5shiv of course): codepen

nav {
margin: 0px auto;
height: 50px;
background-color: gray;
padding: 10px;
border: 2px solid red;
position: relative;
color: white;
z-index: 1;
}


nav:after {
content: '';
background: black;
display: block;
position: absolute;
margin: 10px;
top: 0;
right: 0;
bottom: 0;
left: 0;
z-index: -1;
}

<nav>lorem ipsum dolor sit amet</nav>

the answers said all the possible solutions

I have another one with BOX-SHADOW

here it is JSFIDDLE

and the code

nav {
margin:0px auto;
width:100%;
height:50px;
background-color:grey;
float:left;
padding:10px;
border:2px solid red;
box-shadow: 0 0 0 10px blue inset;
}

it also support in IE9, so It's better than gradient solution, add proper prefixes for more support

IE8 dont support it, what a shame !

I am sorry everyone that this is the solution the true one where you don't have to actually set the padding.

https://jsfiddle.net/techsin/TyXRY/1/

What I have done...

• Applied two gradients on background with both having one start and end color. Instead of using solid color. Reason being that you can't have two solid colors for one background.
• Then applied different background-clip property to each.
• thus making one color extend to content box and other to border, revealing the padding.

Clever if I say so to myself.

div {
padding: 35px;
background-image: linear-gradient(to bottom, rgba(240, 255, 40, 1) 0%, rgba(240, 255, 40, 1) 100%), linear-gradient(to bottom, rgba(240, 40, 40, 1) 0%, rgba(240, 40, 40, 1) 100%);
background-clip: content-box, padding-box;
}

<p>Padding IS COLORED</p>
<div>Mexican’t professor plum charlie chaplin? Facial accessory lorreto del mar Daniel plainview landed gentry circus strongman sam elliott zap rowsdower, lorreto del mar off-piste frightfully nice mustachio landed gentry Daniel plainview zap rowsdower toothbrush
circus strongman boogie nights sam elliott Daniel plainview facial accessory, Daniel plainview man markings boogie nights mr frothy-top sam elliott worn with distinction mustachio zap rowsdower off-piste Daniel plainview toothbrush lorreto del mar frightfully
nice wario facial accessory mr frothy-top landed gentry circus strongman prostate cancer? Rock n roll star gunslinger villain marquess of queensbury en time-warped cabbie off-piste graeme souness en time-warped cabbie, cunning like a fox gunslinger
dodgy uncle clive villain karl marx marquess of queensbury en time-warped cabbie graeme souness rock n roll star off-piste en time-warped cabbie, rock n roll star lemmy dodgy uncle clive graeme souness professor plum en time-warped cabbie villain gunslinger
en time-warped cabbie marquess of queensbury cunning like a fox devilish cad off-piste karl marx. John aldridge basil fawlty landed gentry louis xiii sam elliott brigadier, et sodales cum dick van dyke mouth coiffure louis xiii landed gentry basil fawlty
john aldridge stiff upper lip brigadier crumb catcher sam elliott?</div>

You can do a div over the padding as follows:

<div id= "paddingOne">
</div>
<div id= "paddingTwo">
</div>


#paddingOne {
width: 100;
length: 100;
background-color: #000000;
margin: 0;
z-index: 2;
}
#paddingTwo {
width: 200;
length: 200;
background-color: #ffffff;
margin: 0;
z-index: 3;

the width, length, background color, margins, and z-index can vary of course, but in order to cover the padding, the z-index must be higher than 0 so that it will lay over the padding. You can fiddle with positioning and such to change its orientation. Hope that helps!

P.S. the divs are html and the #paddingOne and #paddingTwo are css (in case anyone didn't get that:)

Use the background-clip and box-shadow properties.

1) Set background-clip: content-box - this restricts the background only to the content itself (instead of covering both the padding and border)

2) Add an inner box-shadow with the spread radius set to the same value as the padding.

So say the padding is 10px - set box-shadow: inset 0 0 0 10px lightGreen - which will make only the padding area light green.

Codepen demo

nav {
width: 80%;
height: 50px;
background-color: gray;
float: left;
padding: 10px; /* 10px padding */
border: 2px solid red;
background-clip: content-box; /* <---- */
box-shadow: inset 0 0 0 10px lightGreen; /* <-- 10px spread radius */
}
ul {
list-style: none;
}
li {
display: inline-block;
}

<h2>The light green background color shows the padding of the element</h2>
<nav>
<ul>
<li><a href="index.html">Home</a>
</li>
<li><a href="/about/">About</a>
</li>
<li><a href="/blog/">Blog</a>
</li>
</ul>
</nav>

For a thorough tutorial covering this technique see this great css-tricks post

Style the <hr> like this to get a solid line.

.line {
height: 10px;
color: black;
margin: 0;
border-style: solid;
background-color: black;
}

<hr class="line">

Another trick:

Stack two divs one on top of the other, then apply different background-clip for each (bottom with padding-box, top with content-box):

.rect {
width: 100px;
height: 50px;
border: red solid 5px;
padding: 10px;
position: absolute;
}
.bottom {
background: yellow padding-box;
}
.top {
background: pink content-box;
}

<div>
<div class="rect bottom"></div>
<div class="rect top"></div>
</div>

Linke:

• The backgound clip property
• Stacking divs

in case you don't want to affect the content background, and you have different padding for each direction, use the following:

div {
width: 440px;
padding: 10px 20px 30px 40px;
box-shadow: inset 0 10px 0 0 lightGreen, inset -20px 0 0 0 lightGreen, inset 0 -30px 0 0 lightGreen, inset 40px 0 0 0 lightGreen;
}

<div>The light green background color shows the padding of the element</div>