为什么我的 div 边距重叠,我如何修复它?

我不明白为什么这些 div 的边缘是重叠的。

.alignright {float: right}
#header .social {margin-top: 50px;}
#header .social a {display: inline-block;}
#header .social .fb {width: 64px; height: 1px; padding-top: 60px; overflow: hidden;}
#header .social .twit {width: 64px; height: 1px; padding-top: 60px; overflow: hidden;}
#header .contact {margin: 20px 70px 20px 0; font-size: 14px; font-weight: bold;}
#header .contact span {color: #FFFFFF;}
#header .search {margin: 10px 0 0;}
<div class="alignright">
<div class="social">
<a href="#" class="twit"></a>
<a href="#" class="fb"></a>
</div><!-- social -->
<div class="contact">
Get in Touch: <span>+44 10012 12345</span>
</div><!-- contact -->
<div class="search">
<form method="post" action="">
<input type="text" value="" name="s" gtbfieldid="28">
</form>
</div><!-- search -->
</div>

picture

91056 次浏览

I think it's a collapsed margin. Only the largest margin between the bottom of the first element and the top of the second is taken into account.

It is quite normal to don't have too much space between two paragraphs eg.

You cannot avoid that with two adjacent elements so you have to enlarge or reduce the larger margin.

EDIT: cf. W3C

Two margins are adjoining if and only if:

  • both belong to in-flow block-level boxes that participate in the same block formatting context
  • no line boxes, no clearance, no padding and no border separate them
  • both belong to vertically-adjacent box edges

So there is no collapsing with float which takes the element out of the flow.

Margins, in contrary to padding (which pads a specific width) is a “do this as a minimum distance”.

It won’t put that distance to all elements.

As you can see, the get in touch block bottom margin is marged to the input box. That is the margin active here. The other margin, top margin from the input, is not in effect, as it’s smaller and does not reach a block-element where it would actually push back the element. The 2 margins overlap and don’t affect one another.

Add a clear div tag between the two objects

If you can not use padding and really need for margin not to overlap, here is one trick:

.btn {
/* hack for a 2px margin */
border-top: 2px #fff solid;
/* this is important if you have a background-color
and don't want to see it underneath the transparent border*/
background-clip: padding-box;
}

Please launch this snippet for demo:

div {
margin: 10px;
background: rgb(48, 158, 140);
padding: 5px 15px;
font-weight: bold;
color: #fff;
}


.fake-margin {
border-top: 10px solid transparent;
background-clip: padding-box;
}
<div>Margin applied is 10px on each sides</div>
<div>the first two have only 10px between them</div>
<div class="fake-margin">the last two have 10 + 10px</div>
<div class="fake-margin">= 20 px</div>

Watch out for display: flex on the parent element.

.flex {
display: flex;
flex-direction: column;
}


.block {
display: block;
}




/* css for example only */
div {
padding: 1em;
background: #eee;
}
p {
font-size: 20px;
margin: 1em 0;
background: pink;
padding: 5px;
}
p:first-child {
margin-top: 0;
}
<h1>display: flex</h1>
<div class="flex">
<p>Aenean eu leo quam. Pellentesque ornare sem lacinia quam venenatis vestibulum. Vivamus sagittis lacus vel augue laoreet rutrum faucibus dolor auctor. Curabitur blandit tempus porttitor.</p>
<p>Duis mollis, est non commodo luctus, nisi erat porttitor ligula, eget lacinia odio sem nec elit. Fusce dapibus, tellus ac cursus commodo, tortor mauris condimentum nibh, ut fermentum massa justo sit amet risus.</p>
<p>Aenean eu leo quam. Pellentesque ornare sem lacinia quam venenatis vestibulum. Vivamus sagittis lacus vel augue laoreet rutrum faucibus dolor auctor. Curabitur blandit tempus porttitor.</p>
<p>Duis mollis, est non commodo luctus, nisi erat porttitor ligula, eget lacinia odio sem nec elit. Fusce dapibus, tellus ac cursus commodo, tortor mauris condimentum nibh, ut fermentum massa justo sit amet risus.</p>
</div>
<h1>display: block</h1>
<div class="block">
<p>Aenean eu leo quam. Pellentesque ornare sem lacinia quam venenatis vestibulum. Vivamus sagittis lacus vel augue laoreet rutrum faucibus dolor auctor. Curabitur blandit tempus porttitor.</p>
<p>Duis mollis, est non commodo luctus, nisi erat porttitor ligula, eget lacinia odio sem nec elit. Fusce dapibus, tellus ac cursus commodo, tortor mauris condimentum nibh, ut fermentum massa justo sit amet risus.</p>
<p>Aenean eu leo quam. Pellentesque ornare sem lacinia quam venenatis vestibulum. Vivamus sagittis lacus vel augue laoreet rutrum faucibus dolor auctor. Curabitur blandit tempus porttitor. Duis mollis, est non commodo luctus, nisi erat porttitor ligula, eget lacinia odio sem nec elit.</p>
<p>Fusce dapibus, tellus ac cursus commodo, tortor mauris condimentum nibh, ut fermentum massa justo sit amet risus.</p>
</div>