绘制2个ACF ggplot2 - 显示最小值颜色

I am trying to plot 2 ACFs in R using ggplot. I use geom_segment() and it works fine, but a slight annoying detail is that depending on the order I declare geom_segment, the plot will overlay the smallest ACFs if I declare these before the largest value. This would not be the problem if one ACF had always a larger value (case in which I would geom_segment that before). I know it sounds confusing, so here is a working example:I am trying to plot 2 ACFs in R using ggplot. I