I have different css files for each record, which will be stored as a file(ContentVersion). I want to load that css in lwc. But getting this error.

Refused to apply style from '' because its MIME type ('text/html') is not a supported stylesheet MIME type, and strict MIME checking is enabled.

I know we can load the js or css files from static resources, but is it possible to load it from files instead of static resource as the css/js files will be dynamic?

  • To understand exactly what you are doing can you put some code? Does your styles start with a comment? If yes please remove the comment and try again. Sep 29, 2020 at 5:35
  • You'll need to set the ContentVersion's FileType correctly.
    – sfdcfox
    Sep 29, 2020 at 11:08
  • @sfdcfox FileType is CSS, I am fetching the VersionData from apex method. Below is the sample code. Promise.all([ loadStyle(this, data.VersionData) ]); Still no luck. Same error. Sep 30, 2020 at 8:19

1 Answer 1


The second parameter must always be a URL. It cannot be plain text that was loaded/parsed directly. You'll want to construct a URL in Apex using Url.getFileFieldUrl:

String fileURL = 
    recordId ,

Then load that resulting URL in your loadStyle call.

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