HTML - no build step
Fastest path: link the compiled CSS and copy markup from ds-check.html.
<link rel="stylesheet" href="my-design-system/dist/my-design-system.min.css" />
<header class="my-header">
<nav class="my-container">…</nav>
</header>
<button class="my-btn">Primary</button>
<button class="my-btn my-btn--outline">Outline</button>All tokens are CSS custom properties under your prefix - change one and the whole system follows. See CSS and Tokens.
Dark mode (one attribute)
<html data-theme="dark">Neutrals invert, brand colors stay. No JS required.
JS only when needed
Accordion, carousel, tooltip work with zero JS. For modal/drawer/tabs add ani.js (~2 KB):
<script src="my-design-system/ani.js"></script>
<button data-my-toggle="#my-modal">Open</button>
<div id="my-modal" class="my-modal">…</div>