Let's assume there is a fixed-width div container, 200px wide. Contained elements are fixed-width inline-block divs, 45px wide. Then let's assume I add one more element to the container. What I would like to achieve is that all the contained elements shrink to maximum possible width and fit in the container without overflowing (40px, assuming there is no whitespace between the elements).
Is this possible with pure CSS?
It is possible with pure CSS3 using the flexbox module. Finding adequate browser support for it is another matter unfortunately.
See it in action (if you are on FF/Chrome/Safari).