请教一下CSS布局排列写法？

Question

<div>
    <em>1</em>
    <em>2</em>
    <em>3</em>
    <em>4</em>
</div>

不改变HTML下如何使用flex或grid，将其排列成下列效果？
1和4自适应，2与3成上下两行，占剩余空间。

Answer 1

用flex布局：

div {
  display: flex;
  justify-content: space-between;
}

em:nth-child(2), em:nth-child(3) {
  flex-grow: 1;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

grid布局：

div {
  display: grid;
  grid-template-columns: auto 1fr auto;
  grid-template-rows: auto auto;
}

em:nth-child(1) {
  grid-column: 1;
  grid-row: 1 / span 2;
}

em:nth-child(2) {
  grid-column: 2;
  grid-row: 1;
}

em:nth-child(3) {
  grid-column: 2;
  grid-row: 2;
}

em:nth-child(4) {
  grid-column: 3;
  grid-row: 1 / span 2;
}

Answer 2

<template>
  <div class="container">
      <div class="one">11111</div>
      <div class="two">2</div>
      <div class="three">3</div>
      <div class="four">444444</div>
  </div>
</template>
<style lang="scss">
.container {
  display: grid;
  grid-template-columns: auto 1fr auto;
  grid-template-areas: 
      "左 中上 右"
      "左 中下 右";
  div{
    background: #ccc;
    border: 5px solid #fff;
  }
}

.one { grid-area: 左;}
.two { grid-area: 中上;}
.three { grid-area: 中下;}
.four { grid-area: 右;}
</style>