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<h1 class="h1">flex inner height 100%</h1>

<div class="wrap">

  <div class="inner">
    <div class="inner_inner">
      <h1>test</h1>
      <div class="textarea">
        <p>test</p>
        <p>test test</p>
      </div>
    </div>
  </div>
  
  <div class="inner">
    <div class="inner_inner">
      <h1>test</h1>
      <div class="textarea">
        <p>test</p>
        <p>test test</p>
        <p>test test</p>
      </div>
    </div>
  </div>
  
  <div class="inner">
    <div class="inner_inner">
      <h1>test</h1>
      <div class="textarea">
        <p>test</p>
        <p>test test</p>
        <p>test test</p>
        <p>test test</p>
      </div>
    </div>
  </div>
  
</div>
 

body {
	width: 100%;
  min-height: 100vh;
	padding-bottom: 50px;
  background-image: linear-gradient(45deg, #F7CAC9 15%, #91A8D0 85%);
}


.h1 {
  margin: 2em;
  font-family: 'Dancing Script', cursive;
  color: rgba(white, .85);
}

.wrap {
  display: flex;
  justify-content: space-around;
}

.inner {
  display: flex;
  background-image: linear-gradient(0deg, rgba(white, .5) 20%, rgba(white,0) 90%) ;
}

.inner_inner {
  display: flex;
  justify-content: space-between;
  flex-direction: column;
}