TypeError: Attempted to assign to readonly property

[abaluta]

Expected behaviour

No errors

Actual behaviour

When the option styledMode is true
JavaScript error: TypeError: Attempted to assign to readonly property.

Live demo with steps to reproduce

https://jsfiddle.net/gh/get/library/pure/highcharts/highcharts/tree/master/samples/highcharts/css/prefers-color-scheme
Enable or disable charts: {styledMode: true|false}

Product version

Highcharts

Affected browser(s)

Safari (Version 16.6 (18615.3.12.11.2))

Discussion of the error on the forum

https://www.highcharts.com/forum/viewtopic.php?f=12&t=50680&sid=9eb5202e6c8ab7f3fde9e4279f785e88

[karolkolodziej]

I can reproduce this issue only in Safari.

Looks like it was introduced in v10.1.0 but I was unable to bissect.
Needs further investigation.

[Samueloyeks]

I also have the same issue on safari

[hubertkozik]

I have prepared a workaround for this bug. You can find it in the demo below. If you want to use it in your project for now you can just copy-paste the IIFE function.

Live demo: https://jsfiddle.net/BlackLabel/9yL3qkg0/