please help me why
<header class="header">
<h1 id="title">Build a Survey Form</h1>
<p id="description">fill out the survey form below</p>
</header>
does not appear in freecodecamp preview
HTML
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Survey Form</title>
<link rel="stylesheet" href="styles.css">
</head>
<body>
<div class="container">
<header class="header">
<h1 id="title">Build a Survey Form</h1>
<p id="description">fill out the survey form below</p>
</header>
<form id="survey-form" value="survey">
<fieldset>
<legend>please fill out the survey</legend>
<label id="name-label">Name <input id="name" type="text" placeholder="enter your name" required /></label><br>
<label id="email-label">Email <input id="email" type="email" placeholder="enter your email" required /></label><br>
<label id="number-label">Age <input id="number" type="number" min="12" max="130" placeholder="age"/></label>
</fieldset>
<fieldset>
<legend>Are you very happy with this course?</legend>
<label><input id="rec" type="radio" name="account-type" value="Rcm" />Recomended
</label><br>
<label><input id="myb" type="radio" name="account-type" value="Maybe" />Maybe</label>
</fieldset>
<fieldset>
<legend>who are you?</legend>
<label>Please select
<select id="dropdown">
<option>(Select One)</option>
<option>student</option>
<option>otodidak</option>
</select>
</label>
</fieldset>
<legend>What will be discussed later?<br>*please choose more than one</legend>
<label>
<input type="checkbox" name="topic" value="framework" />Framework
</label>
<label>
<input type="checkbox" name="topic" value="library"/>Library
</label>
<label>
<input type="checkbox" name="topic" value="cyber" />Cyber Security
</label>
<label for="think">What do you think?
<textarea id="think" name="think" row="3" cols="30"> </textarea>
</label>
<input id="submit" type="submit" value="Submit"/>
</form>
</div>
</body>
</html>
CSS
body {
display: flex;
justify-content: center;
align-items: center;
height: 100vh;
margin: 0;
background-color: cyan;
color: #313036;
font-family: 'Times new roman', serif;
}
#title{
margin-top: 40px;
}
h1,p{
text-align: center;
margin: auto;
}
p{
font-size: 12px;
}
form {
width: 80vw;
max-width: 500px;
min-width: 300px;
border-style: solid;
border-width: medium;
;
}
fieldset{
border: 1px solid black;
background-color: lightblue;
padding: auto;
}
fieldset:last-of-type {
border-bottom: none;
}
label {
display: block;
margin: 0.5rem 0;
}
input,
textarea,
select {
margin: auto;
}
input[type="submit"] {
display: block;
width: 10%;
margin: 1em auto;
height: 2em;
font-size: 1.1rem;
background-color: #3b3b4f;
border-color: white;
min-width: 300px;
}