一、需求：
背景实现透明度0.3，其他组件正常显示
二、代码：
<!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title>
</head>
<style>html,body,#ele-body {width: 100%;height: 100%;margin: 0;padding: 0;}#ele-body {position: relative;}#ele-one {opacity: 0.3;position: absolute;width: 100%;height: 100%;background-color: orange;}#ele-two {position: absolute;width: 300px;height: 300px;text-align: center;line-height: 300px;background-color: blueviolet;left: 0;top: 0;bottom: 0;right: 0;margin: auto;}
</style><body><div id="ele-body"><div id="ele-one"></div><div id="ele-two">春有百花秋有月</div></div>
</body></html>效果显示：
