css code to make header sticky code example

Example 1: stick menu bar in css

.navigation {
   /* fixed keyword is fine too */
   position: sticky;
   top: 0;
   z-index: 100;
   /* z-index works pretty much like a layer:
   the higher the z-index value, the greater
   it will allow the navigation tag to stay on top
   of other tags */
}

Example 2: html how to ensure that the header always on top

#header {
  position: fixed;
}

#content {
  margin-top: 100px;
}