contenido de bootstrap col center
<div class="row">
<div class="col-4 d-flex justify-content-center text-center">
// for image and text
</div>
</div>
ustify-contenido: flex-end
<div class="d-flex justify-content-end">...</div>
flex wrap bootstrap
<div class="d-flex flex-wrap">...</div>
pantalla de arranque flex
<div class="d-flex">I'm a flexbox container!</div>