TLDR: https://svelte.dev/repl/07480ccc08b841048202365140582074?version=3.17.1
Our component not only reacts to local variable changes, you can also change theme values during runtime and see all changes taking effect immediately.
Let's test that! For our demo we add two simple <input> elements and bind their values to our primary and secondary colors:
<script>import theme from './theme.js' // ...</script><input bind:value={$theme.color.primary}/>
<input bind:value={$theme.color.secondary}/>Any valid CSS color codes will work!
Try palevioletred for primary and pink for secondary and see the box respond to your changes immediately.