Navbar not at the top of viewport (Landing page project)

HTML-CSS
1

My navbar does not stay at the top of the viewport currently I am trying to keep the header which the navbar is within at the top of the page using this code:

background-color:white;
  width:100%;
  display:flex;
  flex-direction:column;
  justify-content:center;
  text-align:center;
  margin-bottom:5px;
  height:85px;
  position:fixed block;

from what I have read on the forum you need to use:
position:fixed;

but whenever I do this the header just disappears
any help would be appreciated

2

When I want to sticky the header I use:

position: fixed;
top: 0px;

Might help you.
-Jesse

3

It would help if you posted a link to your page. Do you have a Codepen with the project?

This is invalid CSS BTW

position:fixed block;

It is just fixed not fixed block (block is for the display property, fixed is for the position property)

Here is a fixed nav example, just ignore the float used and stick to flexbox.