Theme management application

Build

To build, run npm install, then npm run build.

To test, run npm test.

Open index.html

Configuration has two levels. The first for configurations categories and the second for configurations items.
Browser is not IE
Given data is always valid
The application works only on ltr languages
There can be more than one item editor open at the same time
When the type is em, rem, px and the value is a "calc" expression, the expression should be valid.
Recursive references does not contain a loop
When a reference is invalid, we print the raw expression