如何将图像放在背景图像的中央？
我正在尝试将图片<div class="shape"></div>放在中心内的图片<div class="hero"></div>上。我可以添加什么编码来上下移动我的需求？
在<div class="shape"></div>图片下方，我想在中间放置一个矩形框。在这个CSS中，我需要添加什么代码才能让我上下移动形状。此外，在CSS中我会使用height:;＆amp; width:;更改框的高度/宽度？
HTML
<body>
<nav class="navbar navbar-default navbar-fixed-top">
<div class="container-fluid">
<!-- Brand and toggle get grouped for better mobile display -->
<div class="navbar-header">
<button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1" aria-expanded="false">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="#"><img src="http://placehold.it/60x60" alt="Your Brand Name"></a>
<h1 class="nav-title">Liam Docherty's Digital Portfolio</h1>
</div>
<!-- Collect the nav links, forms, and other content for toggling -->
<div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
<ul class="nav navbar-nav">
<li><a href="#">Home</a>
</li>
<li class="dropdown">
<a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="true">About Me <span class="caret"></span></a>
<ul class="dropdown-menu">
<li><a href="#">Action</a>
</li>
<li><a href="#section3">Contact</a>
</li>
<li><a href="#">Something else here</a>
</li>
<li><a href="#">Separated link</a>
</li>
<li><a href="#">One more separated link</a>
</li>
</ul>
</li>
<li class="dropdown">
<a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="false">Units <span class="caret"></span></a>
<ul class="dropdown-menu">
<li><a href="#">Action</a>
</li>
<li><a href="#">Another action</a>
</li>
<li><a href="#">Something else here</a>
</li>
<li><a href="#">Separated link</a>
</li>
<li><a href="#">One more separated link</a>
</li>
</ul>
</li>
<li><a href="#">Clients</a>
</li>
<li><a href="#contact-me">Contact Me</a>
</li>
</ul>
</div><!-- /.navbar-collapse -->
</div><!-- /.container-fluid -->
</nav>
<section id="section1" class="section1">
<div class="shape"></div>
<div class="hero"></div>
<a href="#section2"><i class="fa fa-angle-down" style="font-size:100px;"></i></a>
</section>
</body>
CSS
<style>
body {
margin: 0;
padding: 0;
}
.navbar.navbar-default {
background-color: #4D5061;
height: 10vh;
z-index: 100;
}
.navbar.navbar-default ul {
list-style-type: none;
text-align: right;
}
.navbar.navbar-default ul li {
display: inline-block;
}
.dropdown-menu li {
text-align:center
}
.dropdown .dropdown-menu {
background-color: #4D5061;
}
.dropdown .dropdown-menu a {
color: white;
}
.navbar.navbar-default ul li a {
display: inline-block;
padding: 3.5vh 8px 4px;
color: white;
text-decoration: none;
font-size: 14pt;
font-family: 'Roboto', sans-serif;
}
.navbar.navbar-default ul li:after {
content: '';
position: absolute;
right: 50%;
bottom: 0;
left: 50%;
height: 3px;
background-color: #FFFFFF;
border-radius: 9px;
transition: all .2s;
}
.navbar.navbar-default ul li a:hover {
color: white;
}
.nav.navbar-nav,
.nav.navbar-nav>li {
float: none;
}
.navbar.navbar-default ul li:hover:after {
right: 0;
left: 0;
}
.nav>li>a:hover {
background-color: rgba(17, 17, 17, 0.2);
}
#logo {
padding-top: 2vh;
padding-left: 20px;
float: left;
}
.shape {
content:url(http://i1126.photobucket.com/albums/l611/ldocherty1/IMG_0730_zpsiz4dqc47.jpg);
border-radius: 25px;
background:darkgrey;
color:white;
padding:3px;
margin:50px auto 0 auto;
width:150px;
height:150px;
}
.hero {
background-image: url("https://static.pexels.com/photos/48727/pexels-photo-48727.jpeg");
background-attachment: fixed;
position:absolute;
width: 100%;
width: 100vw;
height: 100%;
height: 70vh;
}
section {
position: relative;
height: 95vh;
}
.section1 {
height: 100vh;
text-align: center;
color: white;
}
.section2 {
//height: 95vh;
background-color: #11B5E4;
text-align: center;
color: white;
}
.section3 {
//height: 95vh;
background-color: #EDF7F6;
text-align: center;
color: white;
}
.fa-angle-down {
color: #4D5061;
position: absolute;
bottom: 0px;
}
.fa-angle-up {
color: #4D5061;
position: absolute;
bottom: 0px;
}
.footer {
height: 5vh;
background-color: #4D5061;
text-align: center;
padding:0;
right:0;
bottom:0;
left:0:
}
.nav-title {
font-size: 14pt;
margin:0;
top: 32px;
left: 50px;
width: 100%;
position: absolute;
text-align: center;
color: white;
font-family: 'Roboto', sans-serif;
}
.navbar.navbar-default ul.dropdown-menu li,
.navbar.navbar-default ul.dropdown-menu li a {
position: relative;
display: block;
}
</style>
答案 0 :(得分：2)
要将一个DIV放在另一个DIV上，你将那个应该出现在顶部的那个（=孩子）INTO到另一个（=父元素），例如
<div class="x1"><div class="x2">...content...</div></div>
这些最重要的CSS设置是：
div.x1 {
position: relative;
}
div.x2 {
position: absolute;
top: 30px;
left: 50px;
width: 100px;
height: 50px;
}
上面的所有px值都是完全随机的，它们取决于您的实际情况 - 根据您的需要进行调整。但是你确实需要第二个div的这些或类似的参数。
另外一个矩形可以采用相同的方式处理（如div.x2）。
此外，您可以为那些绝对定位的DIV分配background（只能是一个颜色值），以实际覆盖它们背后的内容。
评论后补充说，关于codepen：
你是用HTML做的另一种方式 - 形状必须在英雄内部
CSS：绝对/相对：其他方式。