W3Schools Tryit Editor

<!DOCTYPE html>
<html>
<head>
<style>
#container {
  width: 80%;
  aspect-ratio: 3/1;
  padding: 40px 0;
  margin: auto;
  border: solid black 2px;
  overflow-x: hidden;
  overflow-y: scroll;
  scroll-snap-type: y mandatory;
}

.blue {
  background-color: lightblue;
  width: 95%;
  aspect-ratio: 3/1;
}

.green {
  background-color: lightgreen;
  width: 80%;
  aspect-ratio: 4/1;
}

.blue, .green {
  margin: 2px;
  scroll-snap-align: start;
  scroll-margin: 20px;
}
</style>
</head>
<body>

<h3>CSS scroll-margin property.</h3>
<p>Scroll-margin property is set on the child elements inside the container, so that snap position is offset by a margin inside the container.</p>
<p>In this case, snap position is set to start in y direction, so the element in focus should snap into place at the very top of the container. But instead, because of the scroll-margin value, the element in focus is offset by 20px margin between child element and container.</p>

</body>
</html>