solid black;
  border-bottom-width: 45px;
  width: 100px;
  height: 100px;
}
.abspos {
  position: absolute;
  width: 50px;
  height: 50px;
  background-color: green;
  align-self: end;
}
</style>
</head>
<body>
<div class="grid">
  <div class="abspos"></div>
</div>
</body>
</html>
