D3 Responsive Zoomable Treemap (D3 v4+)
A Pen created on CodePen.io. Original URL: https://codepen.io/AhmadHemmat/pen/MWzrMPW.
CSS based treemap, D3.js v4 and up
Note: because of % units used for easy CSS responsiveness, treemap tiling can't be modified after window resize (you'd want to re-tile so cells maintain aspect ratio in vertically or horizontally stretched layout). Quite slow – best for smaller datasets.