bootstrap4 弹性盒子-垂直方向

.flex-column 类用于设置弹性子元素垂直方向显示, .flex-column-reverse 用于翻转子元素：

<div class="d-flex flex-column"> <div class="p-2 bg-info">Flex item 1</div> <div class="p-2 bg-warning">Flex item 2</div> <div class="p-2 bg-primary">Flex item 3</div>

</div> <div class="d-flex flex-column-reverse"> <div class="p-2 bg-info">Flex item 1</div> <div class="p-2 bg-warning">Flex item 2</div> <div class="p-2 bg-primary">Flex item 3</div>

</div>