Is such a thing possible using CSS and two inline-block (or whatever) DIV tags instead of using a table?
The table version is this (borders added so you can see it):
I've used flex-grow property to achieve this goal. You'll have to set display: flex for parent container, then you need to set flex-grow: 1 for the block you want to fill remaining space, or just flex: 1 as tanius mentioned in the comments.
flex-grow
display: flex
flex-grow: 1
flex: 1