bootstrap 4 div centro
<div class="d-flex justify-content-start">...</div>
<div class="d-flex justify-content-end">...</div>
<div class="d-flex justify-content-center">...</div>
<div class="d-flex justify-content-between">...</div>
<div class="d-flex justify-content-around">...</div>
alinear columnas en el centro de bootstrap
<!-- Center columns in a Row -->
<div class="row d-flex justify-content-center text-center">
<div class="col-4">
// Add Content
</div>
<div class="col-4">
// Add Content
</div>
<div class="col-4">
// Add Content
</div>
</div>
html center image verticalmente bootstrap
mx-auto mt-auto mb-auto
cómo centrar verticalmente en bootstrap col
<div class="my-auto">
...inner divs and content...
</div>
bootstrap div centro vertical
<div class="jumbotron d-flex align-items-center min-vh-100">
<div class="container text-center">
I am centered vertically
</div>
</div>