If you want to customize Stork to fit in seamlessly with your site, you can write your own CSS to style Stork's generated HTML. If that sounds like too much work, you can use one of the themes here.
To use a Stork theme, include the specified CSS file somewhere in your
<link rel="stylesheet" href="https://files.stork-search.net/basic.css" />
<link rel="stylesheet" href="https://files.stork-search.net/dark.css" />