Flexで2カラム

See the Pen flexで2カラム by takapen (@takapen) on CodePen.

  
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ul {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  margin: 10px;
}
li {
  width: 49%;
  margin-bottom: 16px;
  background: #ccc;
}