What's the difference between hidden and none?

Answer 1

none means no border will show, and the computed border-width is zero.

hidden has the same meaning as none, except when it refers to table borders in cases where two cells share a border, and the table cells have collapsed borders (border-collapse:collapse;). The value hidden ensures that no border is drawn, since hidden takes precedence over all other border styles. If none had been used for one border in the cell, the border would still be drawn, as the adjacent cell’s border would take precedence. 

Ref here: https://www.sitepoint.com/border-style-css-property/#:~:text=none%20means%20no%20border%20will,%2Dcollapse%3Acollapse%3B%20).

Answer 2

Thank you!