JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <div class="group g1">
      <div class="item">Item</div>
      <div class="item">Item</div>
      <div class="item">Item</div>
      <div class="item">Item</div>
      <div class="item">Item</div>
      <div class="item">Item</div>
      <div class="item">Item</div>
    </div>
    <div class="group g2">
      <div class="item">Item</div>
    </div>
</div>

CSS

.container {
  display: flex;
  flex-wrap: wrap;
  flex-direction: column;
  background: #aa0000;
  height: 100px;
}

.group {
  display: flex;
  flex-wrap: wrap;
  flex-direction: column;
  align-content: flex-start;
}

.g1 {
  background: #00aa00;
}

.g2 {
  background: #0000aa;
}