two types of container classes in bootstrap code example
Example: container in bootstrap
Containers
Containers are the most basic layout element in Bootstrap and are required when using our default grid system. Choose from a responsive, fixed-width container (meaning its max-width changes at each breakpoint) or fluid-width (meaning it’s 100% wide all the time).
While containers can be nested, most layouts do not require a nested container.
Syntax:
<div class="container">
<!-- Content here -->
</div>