border bottom class in bootstrap 4

1<span class="border border-primary"></span>
2<span class="border border-secondary"></span>
3<span class="border border-success"></span>
4<span class="border border-danger"></span>
5<span class="border border-warning"></span>
6<span class="border border-info"></span>
7<span class="border border-light"></span>
8<span class="border border-dark"></span>
9<span class="border border-white"></span>
10
11<span class="border-0"></span>
12<span class="border-top-0"></span>
13<span class="border-right-0"></span>
14<span class="border-bottom-0"></span>
15<span class="border-left-0"></span>

1Border-radius
2Add classes to an element to easily round its corners.
3
4<img src="..." alt="..." class="rounded">
5<img src="..." alt="..." class="rounded-top">
6<img src="..." alt="..." class="rounded-right">
7<img src="..." alt="..." class="rounded-bottom">
8<img src="..." alt="..." class="rounded-left">
9<img src="..." alt="..." class="rounded-circle">
10<img src="..." alt="..." class="rounded-0">

1<span class="border">Text</span>
2<span class="border-top">Text</span>
3<span class="border-right">Text</span>
4<span class="border-bottom">Text</span>
5<span class="border-left">Text</span>
6

1<span class="border"></span>
2<span class="border-top"></span>
3<span class="border-right"></span>
4<span class="border-bottom"></span>
5<span class="border-left"></span>

1<img src="..." alt="..." class="rounded">
2<img src="..." alt="..." class="rounded-top">
3<img src="..." alt="..." class="rounded-right">
4<img src="..." alt="..." class="rounded-bottom">
5<img src="..." alt="..." class="rounded-left">
6<img src="..." alt="..." class="rounded-circle">
7<img src="..." alt="..." class="rounded-0">