JSFiddle - React, Tailwind, and code Playground

HTML

<div class="ikigai">
  <div class="header">this is a header</div>
  <div class="content">content</div>
  <div class="footer">footer 12</div>
</div>

CSS

.ikigai {
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
}

.header, .footer {
  height: 80px;
  margin: 10px;
  border: 1px dashed lightgray;
}

.content {
  margin: 10px;
  border: 1px dashed lightgray;
  flex-grow: 1;
}