Using CSS libraries

[avi12]

I'm using the Svelte template and I wish to use it with Svelte Materialify
How do I tell the HTML to load the CSS before it exists, i.e. it will exist upon compiling Svelte?
So far, I've tried adding

<link rel="stylesheet" href="/bulid/popup/popup.css">

but the Vite plugin isn't happy and seeks for popup.css, which doesn't exist yet

So far I've been using rollup-plugin-css-only