"All Buttons Must Die!" is a pure CSS library of buttons. The entire library is just ~15KB minified. Althought the library is still in its early alpha state, it's mostly usable and most buttons are pretty reliable.
With that being said, the library IS in an early alpha state. Use at your own risk
The easiest way is to just include ABMD via CDN
https://cdn.jsdelivr.net/npm/abmd/css/buttons.css
Copy-paste the stylesheet <link> into your <head> to load ABMD's CSS
<link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/npm/abmd/css/buttons.css">
You can also install ABMD with NPM
npm install abmd
And don't forget to include the CSS file!