W3School TIY Editor

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
}

.navbar {
  overflow: hidden;
  background-color: #333;  
  position: fixed;
  bottom: 0;
  width: 100%;
}

.navbar a {
  float: left;
  display: block;
  color: #f2f2f2;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
  font-size: 17px;
}

.navbar a:hover {
  background-color: #ddd;
  color: black;
}

.navbar a.active {
  background-color: #04AA6D;
  color: white;
}

.navbar .icon {
  display: none;
}

@media screen and (max-width: 600px) {
  .navbar a:not(:first-child) {display: none;}
  .navbar a.icon {
    float: right;
    display: block;
  }
}

@media screen and (max-width: 600px) {
  .navbar.responsive .icon {
    position: absolute;
    right: 0;
    bottom:0;
  }
  .navbar.responsive a {
    float: none;
    display: block;
    text-align: left;
  }

}
</style>
</head>
<body>

<div class="navbar" id="myNavbar">
  <a href="#home" class="active">Home</a>
  <a href="#news">News</a>
  <a href="#contact">Contact</a>
  <a href="#about">About</a>
  <a href="javascript:void(0);" style="font-size:15px;" class="icon" onclick="myFunction()">☰</a>
</div>

<div style="padding-left:16px">
  <h2>响应式底部导航菜单</h2>
  <p>请调整浏览器窗口大小，以查看响应式导航菜单的工作方式。</p>
</div>

</body>
</html>