<!DOCTYPE html>
<html>
    <head>
        <style>
            .background {
                position: absolute;
                top: 50px;
                left: 50px;
                width: 140px;
                height: 140px;
                background: blue;
                will-change: transform;
            }

            .container {
                position: absolute;
                top: 100px;
                left: 100px;
                height: 500px;
                width: 500px;
                padding: 10px;
                background-color: orange;
            }

            .content {
                margin: 50px;
                height: 200px;
                background-color: rgba(255, 255, 255, 0.5);
            }

        </style>
    </head>
    <body>
        <div class="background">fixed</div>
        <div class="container">
            container
            <div class="content">fader</div>
        </div>
    </body>
</html>