https://bootstrap button code example
Example 1: bootstrap buttons Sizes
Fancy larger or smaller buttons? Add .btn-lg or .btn-sm for additional sizes.
<button type="button" class="btn btn-primary btn-lg">Large button</button>
<button type="button" class="btn btn-secondary btn-lg">Large button</button>
<button type="button" class="btn btn-primary btn-sm">Small button</button>
<button type="button" class="btn btn-secondary btn-sm">Small button</button>
<button type="button" class="btn btn-primary btn-lg btn-block">Block level button</button>
<button type="button" class="btn btn-secondary btn-lg btn-block">Block level button</button>
<a href="#" class="btn btn-primary btn-lg active" role="button" aria-pressed="true">Primary link</a>
<a href="#" class="btn btn-secondary btn-lg active" role="button" aria-pressed="true">Link</a>
Example 2: bootstrap button drak
<button type="button" class="btn btn-dark">Dark</button>