Style 01
<div class="bd-example">
<a href="#!" class="btn-style1 small"><span>Button</span></a>
<a href="#!" class="btn-style1 medium"><span>Button</span></a>
<a href="#!" class="btn-style1"><span>Button</span></a>
</div>
Style 02
<div class="bd-example">
<a href="#!" class="btn-style1 secondary small"><span>Button</span></a>
<a href="#!" class="btn-style1 secondary medium"><span>Button</span></a>
<a href="#!" class="btn-style1 secondary"><span>Button</span></a>
</div>
Style 03
<div class="bd-example">
<button type="button" class="btn btn-primary">Primary</button>
<button type="button" class="btn btn-secondary">Secondary</button>
<button type="button" class="btn btn-success">Success</button>
<button type="button" class="btn btn-danger">Danger</button>
<button type="button" class="btn btn-warning">Warning</button>
<button type="button" class="btn btn-info">Info</button>
<button type="button" class="btn btn-light">Light</button>
<button type="button" class="btn btn-dark">Dark</button>
<button type="button" class="btn btn-link">Link</button>
</div>
Style 04
<div class="bd-example">
<button type="button" class="btn btn-outline-primary">Primary</button>
<button type="button" class="btn btn-outline-secondary">Secondary</button>
<button type="button" class="btn btn-outline-success">Success</button>
<button type="button" class="btn btn-outline-danger">Danger</button>
<button type="button" class="btn btn-outline-warning">Warning</button>
<button type="button" class="btn btn-outline-info">Info</button>
<button type="button" class="btn btn-outline-light">Light</button>
<button type="button" class="btn btn-outline-dark">Dark</button>
</div>