CSSを使用してレスポンシブなMeetTheTeamページを作成するにはどうすればよいですか？

以下は、HTMLとCSSを使用してレスポンシブな「チームに会う」ページを作成するためのコードです-

例

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
html {
   box-sizing: border-box;
}
body{
   font-family: monospace,serif,sans-serif;
}
img{
   height: 300px;
   width: 100%;
}
*, *:before, *:after {
   box-sizing: inherit;
}
.teamColumn {
   float: left;
   width: 33.3%;
   margin-bottom: 16px;
   padding: 0 8px;
}
@media screen and (max-width: 650px) {
.teamColumn {
   width: 100%;
   display: block;
}
}
.teamCard {
   background-color: rgb(162, 162, 255);
   text-align: center;
   font-size: 20px;
}
.personContainer {
   padding: 0 16px;
}
.personContainer::after, .teamContainer::after {
   content: "";
   clear: both;
   display: table;
}
.Designation {
   color: rgb(15, 0, 100);
   font-weight: bolder;
   font-size: 40px;
}
.contact {
   border: none;
   outline: 0;
   display: inline-block;
   padding: 12px;
   color: white;
   font-weight: bolder;
   background-color: rgb(78, 0, 102);
   text-align: center;
   cursor: pointer;
   width: 100%;
}
.contact:hover {
   background-color: #555;
}
</style>
</head>
<body>
<h1 style="text-align: center;">Responsive Meet the team example </h1>
<div class="teamContainer">
<div class="teamColumn">
<div class="teamCard">
<img src="https://images.pexels.com/photos/839011/pexels-photo-839011.jpeg?auto=compress&cs=tinysrgb&dpr=1&w=500" >
<div class="personContainer">
<h2>Jane Doe</h2>
<p class="Designation">CTO</p>
<p><button class="contact">Contact</button></p>
</div>
</div>
</div>
<div class="teamColumn">
<div class="teamCard">
<img src="https://images.pexels.com/photos/614810/pexels-photo-614810.jpeg?auto=compress&cs=tinysrgb&dpr=1&w=500">
<div class="personContainer">
<h2>Mike Ross</h2>
<p class="Designation">Front End Developer</p>
<p><button class="contact">Contact</button></p>
</div>
</div>
</div>
<div class="teamColumn">
<div class="teamCard">
<img src="https://images.pexels.com/photos/736716/pexels-photo-736716.jpeg?auto=compress&cs=tinysrgb&dpr=1&w=500">
<div class="personContainer">
<h2>John Doe</h2>
<p class="Designation">FullStack Developer</p>
<p><button class="contact">Contact</button></p>
</div>
</div>
</div>
</div>
</body>
</html>