This is the CSS that you are generating:
.mygrb .mx-groupbox.collapsed > .mx-groupbox-header {
background: green;
}
However, ‘mygrb’ is generated on the same DOM node as the ‘mx-groupbox.collapsed’, therefore the selector isn’t working. The CSS should look like this:
.mygrb.mx-groupbox.collapsed > .mx-groupbox-header {
background: green;
}
Try:
.mygrb {
&.mx-groupbox.collapsed {
> .mx-groupbox-header {
background: green; }
}
}