Single price grid component w/ Bootstrap 4 & custom css.

As ya'll can see there's a little issue right at the bottom middle of the columns where there's a bit of white showing. Couldn't figure out a way to round just one bottom corner without rounding the other. Also could figure out how to just round the entire thing together without having to round each part individually. If anyone has any solutions feel free to let me know. That little bit of white will bother me forever.