<html lang="en">
<head>
    <title>iOS 12 iframe + position: fixed + translate3d bug</title>
    <meta charset="UTF-8">
    <meta name="viewport" content="user-scalable=no, initial-scale=1, maximum-scale=1, minimum-scale=1, width=device-width, height=device-height, target-densitydpi=device-dpi">
    <style>
        html, body {
            height: 100%;
            width: 100%;
            margin: 0;
        }

        body {
            height: 1500px;
        }

        iframe {
            width: 100%;
        }
    </style>
</head>
<body>
    <iframe src="iframe.html"></iframe>
</body>
</html>
<html lang="en">
<head>
    <title>iOS 12 iframe + position: fixed + translate3d bug</title>
    <meta name="viewport" content="user-scalable=no, initial-scale=1, maximum-scale=1, minimum-scale=1, width=device-width, height=device-height, target-densitydpi=device-dpi">
    <style>
        #app {
            height: 800px;
            width: 100%;
            box-sizing: border-box;
            font-size: 1rem;
        }

        #gallery {
            position: fixed;
            transform: translate3d(0, 0, 0);
        }

        .item {
            width: 1025px; 
            height: 800px;
            background: lime
        }
    </style>
</head>

<body>
    <div id="app">
        <div id="gallery">
            <div class="item">
              <ol>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
                <li>Part of this div vanishes when scrolled up.</li>
              </ol>
            </div>
        </div>
    </div>
</body>
</html>