图片宽度大于父元素宽度时，水平居中。
如果图片宽度大于父元素宽度，不能使用 margin: 0 auto;或者text-align: center;让图片居中
使用定位
弊端：受图片大小限制
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
div {
800px;
height: 1000px;
background-color: aqua;
margin: 0 auto;
}
img {
position: absolute;
left: 50%;
margin-left: -960px;
}
</style>
</head>
<body>
<div>
<img src="./img.jpg" alt="">
</div>
</body>
</html>
使用transform优化
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
div {
800px;
height: 1000px;
background-color: aqua;
margin: 0 auto;
}
img {
position: relative;
left: 50%;
/* margin-left: -960px; */
transform: translateX(-50%);
}
</style>
</head>
<body>
<div>
<img src="./img.jpg" alt="">
</div>
</body>
</html>
奇技淫巧
margin: 0 -100%;必须和父元素 text-align: center;搭配使用
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
div {
800px;
height: 1000px;
background-color: aqua;
margin: 0 auto;
text-align: center;
}
img {
margin: 0 -100%;
}
</style>
</head>
<body>
<div>
<img src="./img.jpg" alt="">
</div>
</body>
</html>
