example on sticky footer responsive bootstrap
Example 1: sticky footer bootstrap 3
<style>
.footer {
position: fixed;
left: 0;
bottom: 0;
width: 100%;
background-color: red;
color: white;
text-align: center;
}
</style>
Example 2: sticky footer not working bootstrap
/* 2020 - bootstrap 4.5+
Note: - The flex-fill utility was included in Bootstrap 4.1 at later release.
So after that release the extra CSS for flex-fill won't be needed.
Additionally min-vh-100 is included in newer Bootstrap 4 releases */
<div class="d-flex flex-column min-vh-100">
<nav>
</nav>
<main class="flex-fill">
</main>
<footer>
</footer>
</div>