我知道有很多这样的线程，但我似乎无法解决这个width:100%问题。我在菜单上有一个滑动的描述，它比按钮还大。我试过添加box-sizing: border-box;但没有成功。我不知道有什么问题。可能与#mainicons和#mainicons i的边距、填充和两个不同的css代码有关？
我的代码：
#mainicons {
height: 50px;
width: 70px;
position: fixed;
top: 250px;
left: 0px;
text-align: center;
}
#mainicons>a {
position: relative;
margin-top: 20px;
display: flex;
justify-content: center;
align-items: center;
}
#mainicons i {
display: flex;
flex-direction: column;
margin-top: 20px;
height: 40px;
width: 50px;
padding: 10px;
color: #fff;
background: #CE9C87;
text-align: center;
font-size: 15px;
line-height: 40px;
-webkit-transition: all .5s ease;
-moz-transition: all .5s ease;
-o-transition: all .5s ease;
transition: all .5s ease;
}
#mainicons i:hover {
-webkit-box-shadow: inset 7px 0px 0px 0px #CE9C87;
-moz-box-shadow: inset 7px 0px 0px 0px #CE9C87;
box-shadow: inset 7px 0px 0px 0px #CE9C87;
color: #CE9C87;
background: #fff;
-webkit-transition: all .5s ease;
-moz-transition: all .5s ease;
-o-transition: all .5s ease;
transition: all .5s ease;
}
#mainicons span {
color: #CE9C87;
background: #fff;
width: 100%;
height: 100%;
z-index: -1;
font-size: 15px;
position: absolute;
display: flex;
align-items: center;
justify-content: center;
left: -100px;
-webkit-transition: all .5s ease;
-moz-transition: all .5s ease;
-o-transition: all .5s ease;
transition: all .5s ease;
}
#mainicons a:hover>span {
left: 70px;
}<link href="//maxcdn.bootstrapcdn.com/font-awesome/4.1.0/css/font-awesome.min.css" rel="stylesheet">
<body bgcolor="#E6E6FA">
<div id="mainicons">
<a href="/"><i class="fa fa-home"></i><span>Home</span></a>
<a href="/ask"><i class="fa fa-envelope"></i><span>Ask</span></a>
<a href="/submit"><i class="fa fa-pencil "></i><span>Request</span></a>
<a href="/archive"><i class="fa fa-clock-o"></i><span>Archive</span></a>
</div>谢谢你的帮助！：）
最佳答案
移除margin-top: 20px;和#mainicons>a中的#mainicons i
这样地：
http://output.jsbin.com/romotisalo/3
关于html - 宽度: child 比 parent 大100％，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/44184031/