Mistral Contrastin

I did. It complains that centered is listed twice. ``` src/Camfort/Specification/Stencils/Grammar.y: 60: multiple use of 'centered' src/Camfort/Specification/Stencils/Grammar.y: multiple use of 'centered' src/Camfort/Specification/Stencils/Grammar.y: multiple use of 'centered' ```

Alright, I will see if it is an easy change and maybe do a PR soon.

@tomduck that is how it probably should have been from the beginning but I think doing that now would wreak havoc in many documents. @mb21 would you accept a PR...

@jgm I agree it is inelegant but sadly it certainly would break existing documents. I can amend #4269 to behave the same way with IDs if you like?

Meanwhile for others struggling with this, here's an ugly JS workaround based on @mb21's solution to the problem. ```javascript var figures = Array.prototype.slice.call(document.getElementsByClassName("figure"),0) .concat( Array.prototype.slice.call(document.getElementsByTagName("figure"),0)); for (var i = 0;...