How to change colors for 1 data frame on a ggplot for combined 2 dataframes on R?

Question

[Amr]

How to change colors for 1 data frame on a ggplot for combined 2 dataframes on R?

df$Cell_lines = 'cell_one'

data2$Cell_lines = 'cell_two'

df3=rbind(df,data2)

ggplot(df3, aes(x=Variant_Classification, y=Number_of_Genes, col =Cell_lines, fill = Variant_Classification)) + geom_bar(stat="identity",position = 'dodge') + theme_minimal() + labs(title ="cell_one vs cell_two") + theme( axis.title.x=element_blank(), axis.text.x=element_blank(), axis.ticks.x=element_blank())

I have merged 2 dataframes to plot them on R with ggplot, the 2 dataframes plotted on 1 single ggplot graph but both have the same colors but outlined with different colors... due to that its not clear to visualize, so how can i shade every single column for dataframe1. In another way, the plot for example has 6 columns 2 red, 2 blue, 2 purple, one red outlined with green and one red outlined with yellow, one blue outlined with green and one blue outlined with yellow, etc... its not clear like that so I want to make it one red and one red but shaded with black, one blue and one blue shaded with black etc..... in case if you have different idea, its good also. Thanks

[jv]

this is a duplicate post of https://www.biostars.org/p/9539180/#9539180