Sure, here's a more concise and clear version:
"The old variable link (https://bulma.io/documentation/overview/variables/) was broken. I used the Wayback Machine to see where it originally directed and found that the variables page was divided into different sections. The new link is now (https://bulma.io/documentation/customize/#docsNav), which I have updated in the README."
Is this better?
Bulma is a **CSS** framework. As such, the sole output is a single CSS file: [bulma.css](https://github.com/jgthms/bulma/blob/master/css/bulma.css)
-You can either use that file, "out of the box", or download the Sass source files to customize the [variables](https://bulma.io/documentation/overview/variables/).
+You can either use that file, "out of the box", or download the Sass source files to customize the [variables](https://bulma.io/documentation/customize/#docsNav).
There is **no** JavaScript included. People generally want to use their own JS implementation (and usually already have one). Bulma can be considered "environment agnostic": it's just the style layer on top of the logic.