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<!DOCTYPE html>
<html>
<head>
<style>
#div1, #div2{
  width: 40%;
  border: solid black 3px;
  float: left;
  margin: 2px;
}
#div1{
  max-block-size: 100px;
}
#div2{
  block-size: 100px;
}
p.content{
  margin: 0;
  background-color: lightgreen;
  height: 50px;
  animation: mymove 5s infinite;
}
@keyframes mymove {
  50% {height: 150px;}
}
</style>
</head>
<body>
<h1>Max-block-size and block-size comparison</h1>
<p>Content gradually changes size in the same way inside both boxes, but the effects from max-block-size and block-size are different. The box with max-block-size is able to shrink along with its shrinking content:<p>
<div id="div1">
  <p class="content">Div element with max-block-size 100px;</p>
</div>