This is a step by step instruction on how to remove the Blogspt navbar on top of every Blogspot website.There are two codes

  1. To Reduce the Navbar's height
  2. To reduce the Navbar's visibility
Let us, see both the methods:-
Just paste the following code anywhere between the (head) tags
  1. To Reduce the Navbar's height

#navbar-iframe {
height: 0px;
}


     2.  To reduce the Navbar's visibility

#navbar-iframe {
visibility: hidden;
}


But both these methods do leave a gap above the header which was actually meant for the Navbar.To hide this space also just paste this bit of code anywhere between the head tags:
#navbar-iframe {
visibility:hidden;
height:10px;
}