laravel inject css class to element in blade before render

I have a project in which developers can make blade templates and upload to that CMS, and I want to give admin the ability to add custom css classes to html elements inside that template without touching it.

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What I want to achieve is extending blade compiler and read the dom elements and loop through them all and add the custom css classes if set then compile it as normal blade file. how can I get this approach?

Thanks.

via Chebli Mohamed