<div class="d-flex flex-nowrap"> ... </div>
<div class="d-flex flex-sm-nowrap"> ... </div>
<div class="d-flex flex-md-nowrap"> ... </div>
<div class="d-flex flex-lg-nowrap"> ... </div>
<div class="d-flex flex-xl-nowrap"> ... </div>
You don't need to remember all CSS classes. Just use the Bootstrap Editor instead.