JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html>
 <head>
  <meta charset="utf-8">
  <title>transition-duration</title>
  <style>
   body { margin: 0; }
   .menu {
    position: absolute;
    height: 100px; width: 100%;
    background: #fc0;
    border-bottom: 20px solid #333;
    top: -100px;
    /* Анимация */
    -webkit-transition-property: top;
    -moz-transition-property: top;
    -o-transition-property: top;
    transition-property: top;
    -webkit-transition-duration: 2s;
    -moz-transition-duration: 2s;
    -o-transition-duration: 2s;
    transition-duration: 2s;
   }
   .menu:hover { top: 0; }
  </style>
 </head>
 <body>
  <div class="menu">
    А здесь у нас будет своё 
    меню с преферансом и профурсетками.
  </div>
 </body>
</html>