textual/docs/examples/widgets/selection_list_selected.tcss

Screen {
    align: center middle;
}

Horizontal {
    width: 80%;
    height: 80%;
}

SelectionList {
    padding: 1;
    border: solid $accent;
    width: 1fr;
}

Pretty {
    width: 1fr;
    border: solid $accent;
}