Answers for "how to use col sm offset in bootstrap"

bootstrap col-md-5 center

<div class="container">
  <div class="row">
     <div class="col-sm-5 mx-auto">
        Centered
    </div>
  </div>
</div>

bootstrap breakpoints

// Small devices (landscape phones, 576px and up)
@media (min-width: 576px) { ... }

// Medium devices (tablets, 768px and up)
@media (min-width: 768px) { ... }

// Large devices (desktops, 992px and up)
@media (min-width: 992px) { ... }

// Extra large devices (large desktops, 1200px and up)
@media (min-width: 1200px) { ... }