SCSS

HTML

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css">
<div class="banner-message">
  <button class="btn btn-primary">Click Me!</button>
</div>

SCSS

body {
  background: #20262E;
  padding: 20px;
  font-family: Helvetica;
}

.banner-message {
  background: #fff;
  border-radius: 4px;
  padding: 20px;
  text-align: center;
  width: 300px;
  
  btn {
    border-radius: 8px;
    color: orange;
  }
}