I'm trying to change the transparacy of an Svg rectangle element in the svg node from Bart, but can't get it working.
Tried almost every combination fill-opacity with underscore or with dash, the attribute value as string or int. But it will not work, nothing changes regarding the opacity.
Rest of the payload is working fine.
it is very possible you are doing it right but the property is not affected due to svg fill inheritance. For example, have you set the fill="currentColor" attribute?
if you inspect the SVG and edit the attributes directly in the HTML do you see the changes you expect?