fixed vs sticky
You can make your code have a fixed or sticky position and it should still work. I would rather use sticky because if your element is in the document flow the other elements make room for it (this does not account for horizontal scroll bars). This compaired to fixed where your element, being outside the document can overlap or cover other elements and you have to micromanage or constantly adjust your the position of all the elements.
fixed
The element is positioned relative to the viewport or browser window and the element will be outside the document flow
sticky
The element is positioned relative to the parent element and the element will stay in your document flow