Cool book. Just a suggestion here:
ggplot(bar_df,
aes(x = reorder(country, lifeExp), y = lifeExp, fill = country == "Mauritius")) +
geom_col() +
scale_fill_manual(values = c("#dddddd", "#1380A1"), guide = F) +
geom_hline(yintercept = 0, size = 1, colour="#333333") +
bbc_style() +
coord_flip() +
labs(title="Reunion is highest",
subtitle = "Highest African life expectancy, 2007") +
theme(panel.grid.major.x = element_line(color="#cbcbcb"),
panel.grid.major.y = element_blank())