[Vuejs]-Basic vuetify layout issues. I'm struggling to keep 3 flex elements from expanding past screen height

You need to first understand how v-flex inside v-layout works with prop column works.

When Column prop is set. v-flex takes the available height(not the screen-height/content-height) and divide it to 12 point grid system.

All you need to do is put height of the container (here v-layout). That will solve your problem.

I hope it helps.