Spacing is a CSS issue, not a JS issue.
There are a few ways to add CSS. If you want the styles applied across your whole site, you should write your styles in a stylesheet (file ending .css) and add it to your page template(s) or in your settings (Settings > Website > Pages > CSS & Stylesheets).
If you want your styles applied to one page only and you have a css file, you can add it to a page in the settings or, if you don’t have a stylesheet, you can write the css in the advanced settings of a page in header or footer HTML like
<style>
/* styles here */
</style>