1. What are utility classes in Bootstrap and why are they popular?
Utility classes are tiny single purpose helpers, like spacing, colors, display, and text alignment. You compose them in HTML to style without writing new CSS files. They are popular because they speed up work and keep designs consistent. You make small changes close to the markup, avoid cascade surprises, and reduce custom CSS debt.
<div class='p-3 bg-light text-center'>Hello utilities</div>