top nav bar blocking top content of the page

Answer 1

Add this:

.navbar {
  position: relative;
}

Answer 2

Two problems will happen here:

1. Page load (content hidden)
2. Internal links like this will scroll to the top, and be hidden by the navbar:

<nav>...</nav>              <!-- 70 pixels tall -->
<a href="#hello">hello</a>  <!-- click to scroll down -->
<hr style="margin: 100px">
<h1 id="hello">World</h1>   <!-- Help!  I'm 70 pixels hidden! -->

Bootstrap 4 w/ internal page links

To fix 1), as Martijn Burger said above, the bootstrap v4 starter template css uses:

body {
  padding-top: 5rem;
}

To fix 2) check out this issue. This code mostly works (but not on 2nd click of same hash):

window.addEventListener("hashchange", function() { scrollBy(0, -70) })

This code animates A links with jQuery (not slim jQuery):

  // inline theme global code here
  $(document).ready(function() {
    var body = $('html,body'), NAVBAR_HEIGHT = 70;
    function smoothScrollingTo(target) {
      if($(target)) body.animate({scrollTop:$(target).offset().top - NAVBAR_HEIGHT}, 500);
    }
    $('a[href*=\\#]').on('click', function(event){
      event.preventDefault();
      smoothScrollingTo(this.hash);
    });
    $(document).ready(function(){
      smoothScrollingTo(location.hash);
    });
  })

Answer 3

you should add

#page {
  padding-top: 65px
}

to not destroy a sticky footer or something else

Answer 4

you can set margin based on screen resolution

@media screen and (min-width:768px) and (max-width:991px) {
body {
    margin-top:100px;
}

@media screen and (min-width:992px) and (max-width:1199px) {
  body {
    margin-top:50px;
  }
}

body{
  padding-top: 10%;
}

#nav{
   position: fixed;
   background-color: #8b0000;
   width: 100%;
   top:0;
}

Answer 5

As seen on this example from Twitter, add this before the line that includes the responsive styles declarations:

<style> 
    body {
        padding-top: 60px;
    }
</style>

Like so:

<link href="Z/bootstrap/css/bootstrap.min.css" rel="stylesheet" />
<style type="text/css">
    body {
        padding-top: 60px;
    }
</style>
<link href="Z/bootstrap/css/bootstrap-responsive.min.css" rel="stylesheet" />

Answer 6

The best solution I've found so far, that does not involve hard coding heights and breakpoints is to add an extra <nav... tag to the markup.

<nav class="navbar navbar-expand-md" aria-hidden="true">
    <a class="navbar-brand" href="#">Navbar</a>
</nav>
<nav class="navbar navbar-expand-md navbar-dark bg-dark fixed-top">
    <a class="navbar-brand" href="#">Navbar</a>

By doing it this way the @media breakpoints are identical, the height is identical (provided your navbar-brand is the tallest object in the navbar but you can easily substitute another element in the non fixed-top navbar.

Where this fails is with screen readers which will now present 2 navbar-brand elements. This points at the need for a not-for-sr class to prevent that element from showing up for screen readers. However that class does not exist https://getbootstrap.com/docs/4.0/utilities/screenreaders/

I've tried to compensate for the screen reader issue with aria-hidden="true" but https://www.accessibility-developer-guide.com/examples/sensible-aria-usage/hidden/ seems to indicate this will probably not work when the screen reader is in focus mode which is of course the only time you actually need it to work...