bootstrap fixed-top "border" code example
Example 1: position bootstrap 5
<div class="position-static">...</div>
<div class="position-relative">...</div>
<div class="position-absolute">...</div>
<div class="position-fixed">...</div>
<div class="position-sticky">...</div>
Example 2: position bootstrap 5
<div class="position-relative">
<div class="position-absolute top-0 start-0 translate-middle"></div>
<div class="position-absolute top-0 start-50 translate-middle"></div>
<div class="position-absolute top-0 start-100 translate-middle"></div>
<div class="position-absolute top-50 start-0 translate-middle"></div>
<div class="position-absolute top-50 start-50 translate-middle"></div>
<div class="position-absolute top-50 start-100 translate-middle"></div>
<div class="position-absolute top-100 start-0 translate-middle"></div>
<div class="position-absolute top-100 start-50 translate-middle"></div>
<div class="position-absolute top-100 start-100 translate-middle"></div>
</div>