Please add better docs and examples

As a css-in-js newbie, i have really no idea how to use this lib when i read only the website.

After study the code and the examples it got clearer. But big waste of time, if everybody has to do that.

You should add a sentence for which benefit this lib is absolute needed and superior to other solutions.
E.g. why should i use this and not the things inlcuded in styled-components like theming?
`smaller virtual DOM updates` for a newbie like me, how, what perfomance gain could i expect?

Example from Webpage:
What are tokens?
Why i need and define tokens?
Confusing example "Create themeable CSS Snipptes": What is gradientStartColor variable? is it mistyped startColor?

Describe the api:
Which parameters has createVar?
How to access them? with .val, with .toStyle(...)?
createGlobalTheme with scope without scope `""`, difference?

Start with the website documentation and examples, then inspect the documented createVar and createGlobalTheme entry points. Clarify the library's benefits, token concepts, the gradientStartColor example, createVar parameters and access methods, and scoped versus unscoped createGlobalTheme usage; done means a CSS-in-JS newcomer can follow the examples without studying the source.

Written by the indexing model from the issue text.