css tooltip popup position goes off page

I have a css only tooltip which loads a span as a tooltip when you hover over the link. However this is positioned with CSS but if the link is near to the top of a page or side then the tooltip goes off the side/top of the page. Is there a way with css to make this change or will I have to rely on JS? I have started to try to put something together with Jquery but would rather use CSS if possible.
js fiddle at https://jsfiddle.net/gtoprh21/12/
html

$( ".ktooltip" )
.mouseover(function(e) {
   var mousex = e.pageX + 20; //Get X coordinates
    var mousey = e.pageY + 10; //Get Y coordinates
   if((mousey+100)>$(window).height())
   {

    $('.tooltip')
    .css({ top: mousey-100 ,left: mousex })

   }
   else if((mousex+200)>$(window).width())
   {
      $('.tooltip')
    .css({ top: mousey ,left: mousex-200})

   }
   else
    {
   $('.tooltip')
    .css({ top: mousey, left: mousex })

    }
})

.ref, .refs {
  position:relative;
}
/*added a text indent to overide indent styles further down*/
.ktooltip {
    display: inline-block;
    text-indent:0em;
}

.ref .ktooltiptext, .refs .ktooltiptext {
  visibility:hidden;
  width: 200px;
  background: #fff;
  border-radius: 6px;
  padding: 5px 5px;
  top: -40px;
  left: 10px;
  border:2px solid grey;
  line-height: normal;

    /* Position the tooltip */
    position: absolute;
    z-index: 1;
}

.ref:hover .ktooltiptext, .refs:hover .ktooltiptext {
    visibility: visible;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<p>
 <span id="edtxt.trans1" class="tei l">My hope is in a bishop,
 <!--link to a reference -->
   <sup class="ref expl">
     <a href="#edtxt-explnote1" id="reference-to-edtxt-explnote1" class="ktooltip">1</a>
       <!-- lhe reference in a tooltip -->
       <span class="ktooltiptext">According to tradition <span style="name">Nicholas</span> was
 bishop of Myra in Lycia (south-west Turkey today).</span>
   </sup>
  </span><br>
  <span id="trans2" class="tei l">and in almighty God and his never-ending miracles.</span><br>
  <span id="trans3" class="tei l">Generous Saint Nicholas holds an office,</span><br>
  <span id="trans4" class="tei l">there is a gold symbol in his sign.
    <!-- likn to ref -->
    <sup class="ref expl">
      <a href="#edtxt-explnote2" id="reference-to-edtxt-explnote2" class="ktooltip">2</a>
        <!-- the tooltip -->
        <span class="ktooltiptext"> One of <span style="">Nicholas’s</span> symbols was three 
<sup>bags</sup> of gold <span style="font-variant: small-caps;">which</span> were the <span style="color:
 red;">dowry</span> he provided <span style="color: blue;">for</span> three <span style="color: green;">girls
</span>
        </span>
    </sup>
   </span><br>
   </p>

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