defs to define gradient zones in styledmode

[jslul]

Would it be possible to somehow add defs, like in the example below , to define gradients etc. from css in styledmode? Using JS inside highcharter would be fine.

https://jsfiddle.net/gh/get/library/pure/highcharts/highcharts/tree/master/samples/highcharts/css/gradient/

I see there used to be a hc_defs for pattern fills.

Would appreciate it