CSSとJavaScriptでホバーのタブを変更するにはどうすればよいですか？

CSSとJavaScriptでホバーのタブを変更するには、コードは次のとおりです-

例

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
* {box-sizing: border-box}
.tab {
   float: left;
   border: 1px solid #ccc;
   background-color: #f1f1f1;
   width: 30%;
   height: 300px;
}
.tab button {
   display: block;
   background-color: inherit;
   color: black;
   padding: 22px 16px;
   width: 100%;
   border: none;
   outline: none;
   text-align: left;
   cursor: pointer;
   font-size: 17px;
}
.tab button:hover {
   background-color: #ddd;
}
.tab button.active {
   background-color: #ccc;
}
.tabcontent {
   float: left;
   padding: 0px 12px;
   border: 1px solid #ccc;
   width: 70%;
   border-left: none;
   height: 300px;
   display: none;
}
.clearfix::after {
   content: "";
   clear: both;
   display: table;
}
</style>
</head>
<body>
<h2>Demo Heading Tabs</h2>
<p>Get the Department info by hovering over tabs:</p>
<div class="tab">
<button class="tablinks" onmouseover="demo(event, 'Marketing')">Marketing</button>
<button class="tablinks" onmouseover="demo(event, 'Operations')">Operations</button>
<button class="tablinks" onmouseover="demo(event, 'Finance')">Finance</button>
<button class="tablinks" onmouseover="demo(event, 'IT')">IT</button>
</div>
<div id="Marketing" class="tabcontent">
   <h3>Marketing</h3>
</div>
<div id="Operations" class="tabcontent">
   <h3>Operations</h3>
</div>
<div id="Finance" class="tabcontent">
   <h3>Finance</h3>
</div>
<div id="IT" class="tabcontent">
   <h3>IT</h3>
</div>
<div class="clearfix"></div>
<script>
function demo(e, dept) {
   var i, content, links;
   content = document.getElementsByClassName("tabcontent");
   for (i = 0; i < content.length; i++) {
      content[i].style.display = "none";
   }
   links = document.getElementsByClassName("tablinks");
   for (i = 0; i < links.length; i++) {
      links[i].className = links[i].className.replace(" active", "");
   }
   document.getElementById(dept).style.display = "block";
   e.currentTarget.className += " active";
}
</script>
</body>
</html>