I final find the solution, to make it in absolute position but no idea how to change the background color of the sticky menu when scroll down the page
Absolute is the way to go. Also if you use a class to set the background colour, you can set the background of the Nav Bar to a solid or semi-tranparent colour, add a little bit of padding so Nav Bar isnt tight to the edge of the background container edge, in the same class you can also add a radius value to corners and overflow to hidden if you want round corners. Don’t forget to switch between breakpoint views to change to fine tune settings to suit individual screens. If you want it to stay put on scroll you can do the following in this thread all applied to the same class. Floating navigation bar - #4 by SpookyDoo