代码示例：（标识：css_css_image_overlay_slideleft）
<!DOCTYPE html>
<html>
<head>
<style>
.container {
position: relative;
width: 50%;
}
.image {
display: block;
width: 100%;
height: auto;
}
.overlay {
position: absolute;
bottom: 0;
left: 0;
right: 0;
background-color: #008CBA;
overflow: hidden;
width: 0;
height: 100%;
transition: .5s ease;
}
.container:hover .overlay {
width: 100%;
}
.text {
white-space: nowrap;
color: white;
font-size: 20px;
position: absolute;
overflow: hidden;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
-ms-transform: translate(-50%, -50%);
}
</style>
</head>
<body>
<h1>滑入（从左）</h1>
<div class="container">
<img src="/static/demo/images/avatar.png" alt="Avatar" class="image">
<div class="overlay">
<div class="text">Hello World</div>
</div>
</div>
</body>
</html>
