https://getbootstrap.com/docs/5.1/components/buttons/

<!-- btn-primary -->
<!-- btn-outline-primary 등등등 -->
<div class="btn-group">
	<button type="button" class="btn btn-primary">Primary</button>
	<button type="button" class="btn btn-outline-secondary">Secondary</button>
	<button type="button" class="btn btn-success">Success</button>
	<div class="btn btn-outline-primary">ABC</div>
</div>