Answers for "does bootstrap set the size of the viewpoint"

bootstrap height 100vh class

<div class="container-fluid vh-100"></div>

container bootstrap

<div class="container-sm">100% wide until small breakpoint</div>
<div class="container-md">100% wide until medium breakpoint</div>
<div class="container-lg">100% wide until large breakpoint</div>
<div class="container-xl">100% wide until extra large breakpoint</div>