Add in a "fudge factor"
Add in a "fudge factor"

allowing the sticky behaviour to activate at an offset other than the
container hitting the top of viewport. Config’d by adding a data
attribute to the fixed sticky element, e.g.
data-fixedstickyfudgetop="65" will start sticky behaviour 65px AFTER
the sticky container has hit the top of viewport.

pixelthing/fixed-sticky