How to style IonContent scrollbar?

I have (thick scrollbar)

I want (thin scrollbar) :

I achieved this look in dev-tools with code:

.scroll-y {
	overflow-y: auto;
	scrollbar-width: thin;
	scrollbar-color: lightgray white;
}

But when I tried to save it in my css, I can’t affect on this element…

Solution is:

ion-content::part(scroll) {
	overflow-y: auto;
	scrollbar-width: thin;
	scrollbar-color: lightgray white;
}