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Bootstrap class: .flex-*-wrap

<div class="d-flex flex-wrap"> ... </div>
<div class="d-flex flex-sm-wrap"> ... </div>
<div class="d-flex flex-md-wrap"> ... </div>
<div class="d-flex flex-lg-wrap"> ... </div>
<div class="d-flex flex-xl-wrap"> ... </div>

Preview

Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item