Styling popup of ComboBox

I’ve tryed to set a style to suggestpopup of ComboBox with:
.v-filterselect-prova {
.v-filterselect-button{
color: red;
}
.v-filterselect-input{
color: red;
}
.v-overlay-container{
.v-filterselect-suggestpopup{
background: yellow !important;
text-color: red !important;
}
}
}
button and input are ok but for suggestpopup nothing work.
Where is my mistake?
Thnaks to all for helping