How to change the icon/toggle color of a mat-expansion-panel?

I have already tried to use:

.mat-expansion-panel-header{
color: #fff;
}
.mat-expansion-panel-header::after{
color: #fff;
}
.mat-expansion-panel{
color: #fff;
}
.mat-expansion-panel::after{
color: #fff;
}

.mat-focus-indicator{
color: #fff;
}

.mat-expansion-indicator{
color: #fff;
}

.mat-expansion-indicator::after{
color: #fff;
}


Example I've also tried placing a custom class, also placing the style directly on the element and I can't get it to take the color I want to use. Help me

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