A Beginner's Guide to the Latest Bootstrap 5 Utilities - Designmodo
Bootstrap Borders - examples & tutorial
Fix Border styling with Bootstrap library hard overrides over borders [#3230802] | Drupal.org
Bootstrap Border - Studytonight
css - How to use border with Bootstrap - Stack Overflow
Bootstrap on Twitter: "v5.2.0 brings an updated border-radius to Bootstrap. Subtle and refreshing. 😌 Also includes new global CSS variables like `--bs- border-radius` and two new classes, `.rounded-4` and `.rounded-5`. Peep the PR