Fixed position but relative to container

Question

I am trying to fix a div so it always sticks to the top of the screen, using:

position: fixed;
top: 0px;
right: 0px;

However,

Answer 1

position: sticky that is a new way to position elements that is conceptually similar to position: fixed. The difference is that an element with position: sticky behaves like position: relative within its parent, until a given offset threshold is met in the viewport.

In Chrome 56 (currently beta as of December 2016, stable in Jan 2017) position: sticky is now back.

https://developers.google.com/web/updates/2016/12/position-sticky

More details are in Stick your landings! position: sticky lands in WebKit.