Recreate this simple pure CSS hover blocks effect using this snippet from Zane Hannan AU. When you hover over the blocks you get a box shadow effect and it will stack one over the other on smaller screen devices.
If you are having trouble with the pen, try the archived copy on GitHub
See the Pen (Responsive Fork) Flexible Hover Blocks by Zane Hannan AU (@ZaneHannanAU) on CodePen.0