<!-- background & border -->
<div class="card bg-theme mb-3" data-bs-theme="dark">
  <div class="card-header fw-bold">...</div>
  <div class="card-body">
    <h5 class="card-title">...</h5>
    <p class="card-text text-body text-opacity-75">...</p>
  </div>
</div>

<!-- border & color -->
<div class="card border-theme mb-3">
  <div class="card-header border-theme fw-bold small text-theme">...</div>
  <div class="card-body">
    <h5 class="card-title text-theme">...</h5>
    <p class="card-text text-theme text-opacity-75">...</p>
  </div>
</div>