CSS Borders - Useful for debugging

This is a powerful debugging tool for visualizing how CSS rules are being interpreted:

It’s analogous to using tracing rather than debuggers in C. It’s a much less fiddly way to quickly see all the borders in CSS layout - compared to inspecting elements in the browser one by one.

Have a DEBUG.css file which allows one to comment or uncomment this out.

One can use a Javascript function to call from the console to recursively display the borders.