W3Schools Tryit Editor

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

.blue {
  background-color: lightblue;
  height: 95%;
  aspect-ratio: 1/2;
}

.green {
  background-color: lightgreen;
  height: 50%;
  aspect-ratio: 2/1;
}

.blue, .green {
  display: inline-block;
  margin: 5px;
  scroll-snap-align: center;
}
</style>
</head>
<body>

<h3>CSS scroll-snap-align property.</h3>
<p>Scroll-snap-align property is set on scrollable child elements inside the container, to snap on center position.</p>
<p>Drag the scrollbar horizontally inside the container box, let go, and see the scroll-snap-align center effect.</p>
<p>Click on a box, then navigate through the blue and green boxes with the left and right arrow keys.</p>

</body>
</html>

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<!DOCTYPE html><html><head><style>#container {  width: 80%;  aspect-ratio: 2/1;  margin: auto;  border: solid black 2px;  overflow-x: scroll;  overflow-y: hidden;  white-space: nowrap;  scroll-snap-type: x mandatory;}​.blue {  background-color: lightblue;  height: 95%;  aspect-ratio: 1/2;}​.green {  background-color: lightgreen;  height: 50%;  aspect-ratio: 2/1;}​.blue, .green {  display: inline-block;  margin: 5px;  scroll-snap-align: center;}</style></head><body>​<h3>CSS scroll-snap-align property.</h3><p>Scroll-snap-align property is set on scrollable child elements inside the container, to snap on center position.</p><p>Drag the scrollbar horizontally inside the container box, let go, and see the scroll-snap-align center effect.</p><p>Click on a box, then navigate through the blue and green boxes with the left and right arrow keys.</p>​<div id="container">  <div class="blue"></div>  <div class="green"></div>  <div class="blue"></div>  <div class="green"></div>  <div class="blue"></div>