Flexbox，如何在400px保持至少2个cols？

Question

https://codepen.io/leon-yum/pen/XYpgzj?editors=1100

我试图确保在移动设备（400px及以下）上我的flexbox网格粘贴到2个cols / box。无论我做什么，它都会捕捉到1列，或者每行分别保持3个col或4个col。

预计宽度为400px：

结果：

HTML

<div class="flex-grid-thirds">
  <div class="col">This little piggy went to market.</div>
  <div class="col">This little piggy stayed home.</div>
  <div class="col">This little piggy had roast beef.</div>
</div>

<div class="flex-grid-four">
  <div class="col">This little piggy went to market.</div>
  <div class="col">This little piggy stayed home.</div>
  <div class="col">This little piggy had roast beef.</div>
  <div class="col">This little piggy had roast beef.</div>
</div>

CSS

.flex-grid-thirds,
.flex-grid-four {
  display: flex;
  justify-content: space-between;
  margin-bottom: 20px;
}

.flex-grid-thirds .col {
  width: 32%;
}

.flex-grid-four .col {
  width: 24%;
}

@media (max-width: 400px) {
  .flex-grid-thirds,
  .flex-grid-four {
    .col {
      width: 40%;
    }
  }
}

* {
  box-sizing: border-box;
}
body {
  padding: 20px;
}
.flex-grid { 
  margin: 0 0 20px 0;
}
.col {
  background: salmon;
  padding: 20px;
}

Answer 1

以下是工作解决方案：https://codepen.io/anon/pen/vrgZVa?editors=1100。 您只需要将所有项目放在一个包装元素中（现在您有2个元素），并为此包装器提供flex-wrap: wrap属性。还有一件事要做：给你的商品宽度（百分比是可取的），如果你给他们width: 50%，你会有2列，如果width: 33% - 3列，依此类推。我没有触及边距和这么小的东西，只是展示你的要求：

＆＃13;

＆＃13;

.flex-grid {
  display: flex;
  justify-content: space-between;
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.flex-grid-thirds .col {
  width: 32%;
}

.flex-grid-four .col {
  width: 24%;
}

@media (max-width: 400px) {
  .flex-grid {
    .col {
      width: 50%;
    }
  }
}

* {
  box-sizing: border-box;
}

body {
  padding: 20px;
}
.flex-grid { 
  margin: 0 0 20px 0;
}
.col {
  background: salmon;
  padding: 20px;
}

＆＃13;

<div class="flex-grid">
  <div class="col">This little piggy went to market.</div>
  <div class="col">This little piggy stayed home.</div>
  <div class="col">This little piggy had roast beef.</div>
  <div class="col">This little piggy went to market.</div>
  <div class="col">This little piggy stayed home.</div>
  <div class="col">This little piggy had roast beef.</div>
  <div class="col">This little piggy had roast beef.</div>
</div>

＆＃13;

＆＃13;

＆＃13;