  margin-block: 50px;
    block-size: 0px
}
.with-border-and-margin {
    border: 1px solid black;
    margin-block-start: 30px;
}
</style>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/check-layout-th.js"></script>
</head>
<body onload="checkLayout('item')">
    <container>
        <item data-expected-margin-top="0" class="collapsed">
            <item data-expected-margin-top="0" class="collapsed"></item>
        </item>
 