使用 left: 明确定位我的图像正确放置它,但是当我删除 left: 并用 margin-left: auto 和 margin-right: auto 替换它时,它被定位在左侧。我做错了什么?
<body>
<div id = "main_header" href="http://xxx" >
<img id = "logo" src="logo.png"/>
<h1 id = "main_title">Title</h1>
</div>
body {
position:relative;
background-image: url("large_background.png");
font-family: Helvetica;
margin: 0; /* Amount of negative space around the outside of the body */
padding: 0; /* Amount of negative space around the inside of the body */
}
#main_header {
position: relative;
}
#logo {
position:absolute;
top: 5px;
left: 140px;
height: 50px;
width: 50px;
}