CSS diagonal lines - how to fit into its parent element??

How can I make a diagonal line fill in and fit into a box (just pure css - without any use of background image)? ...

Responsive diagonal lines css?

I need help with setting a diagonal line in css to fit into many resolutions via mobile. Theres a div with 100% widt...

D3 diagonal using coordinates instead of objects?

I am looking for a way to create a line like the one you get using d3.svg.diagonal but instead of using source and t...