internal link anchor to take as reference the top navigation bar instead the top of the screen

Question

Hello I'm using internal links in a page that also uses a fixed top navigation bar. As you may have guessed already, the header of the seccion linked is left below that top bar as the browser scrolls the top of the screen to that point and not the border of the top bar. How can I make up por this so the header of each linked section is left just below the topbar? Thank you!