<!DOCTYPE html>
<link rel="help" href="https://drafts.csswg.org/css-align-3/#baseline-rules">
<style>
#target {
display: grid;
grid-template: 50px 50px 50px / 50px 50px;
grid-auto-flow: column;
align-items: last baseline;
width: 200px;
border: solid 3px;
position: relative;
line-height: 0;
font-size: 20px;
}
span {
display: inline-block;
width: 1em;
height: 1em;
outline: solid cyan 3px;
outline-offset: -3px;
}
</style>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/check-layout-th.js"></script>
<body onload="checkLayout('#target > div')">
<div id="target">
<div style="grid-area: 3 / 1; margin-bottom: 10px;" data-offset-y="100"><span></span><br><span></span></div>
<div style="grid-area: 1 / 2 / 4 / 2;" data-offset-y="100"><span></span><br><span></span></div>
</div>