I am trying to make the red line move above the hovered menu item, then disappear when no menu item is selected. I am very new to Jquery so really stuck on how to do this.

Does anyone have any ideas?

The code is at http://jsfiddle.net/xpvt214o/276727/

HTML

<div class="topnav" id="myTopnav">
	<a href="#home" id="homeLink" class="active">Home </a>
   <div class="dropdown">
    <button class="dropbtn">About
      <i class="fa fa-caret-down"></i>
    </button>
    <div class="dropdown-content">
      <a href="#">Our Vision</a>
      <a href="#">Our Story</a>
      <a href="#">Leadership</a>
    </div>
  </div> 
  <a href="#contact">News</a>
  <div class="dropdown">
    <button class="dropbtn">Get Involved
      <i class="fa fa-caret-down"></i>
    </button>
    <div class="dropdown-content">
      <a href="#">Events</a>
      <a href="#">Social Media</a>
      <a href="#">Regional Branches</a>
    </div>
  </div> 
  <a href="#about">Donate</a>
<a href="#about">Join</a>
  <a href="javascript:void(0);" style="font-size:15px;" class="icon" onclick="myFunction()">&#9776;</a>
</div>

<div class="main-nav__line" style="width: 75px; left: 288.594px;"></div>

CSS

.topnav {
  overflow: hidden;
  background-color:  #e6e6e6;
	 font-family: 'Lato', sans-serif;
	font-style: normal;
	font-variant: normal;
}

.topnav a {
  float: left;
  display: block;
  color: black;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
  font-size: 2em;
}

.active {
  color: white;
	
}

.topnav .icon {
  display: none;
}

.dropdown {
    float: left;
    overflow: hidden;
	
}

.dropdown .dropbtn {
    font-size: 2em;    
    border: none;
    outline: none;
    padding: 12px 16px;
    background-color: inherit;
    font-family: inherit;
    margin: 0;
}

.dropdown-content {
    display: none;
    position: absolute;
    background-color: #afafaf;
    min-width: 160px;
    box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
    z-index: 1;
}

.dropdown-content a {
    float: none;
    color: black;
    padding: 12px 16px;
    text-decoration: none;
    display: block;
    text-align: left;
}

.topnav a:hover, .dropdown:hover .dropbtn {
  color: #2d9e94;
}

.dropdown-content a:hover {
    background-color: #ddd;
    color:#2d9e94;
}

.dropdown:hover .dropdown-content {
    display: block;
}

.main-nav__line {
    position: absolute;
    top:0;
    height: 4px;
    width: 0px;
    background-color: #e91d27;
    transition:all 0.2s ease-in-out;
    left:150px;
}

Jquery

$('ul.myTopnav').hover(function(){           =
  $('.main-nav__line'.toggle()); 
})

I have tried to get it to hover using the Jquery "hover" command but I cannot get it to work.