Show only selected item and hide the rest for single selected item filtering
%root%:has(.brx-option-active) li:not(.brx-option-active) {
display: none;
}
tested setup;

Show only selected item and hide the rest for single selected item filtering
%root%:has(.brx-option-active) li:not(.brx-option-active) {
display: none;
}
tested setup;
