W3Schools Tryit Editor

<!DOCTYPE html>
<html>
<title>W3.CSS</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://www.w3schools.com/w3css/5/w3.css">
<body>

<div class="w3-container">
  <h2>Welcome to Sailing</h2>
  <p>Sailing comprises wind propulsion of a craft by means of sails and steering it over water,
  ice or land, depending on the type of craft. A sailor manages the force of the wind on the
  sails by adjusting their angle with respect to the moving sailing craft...</p>
  <p>
  <button onclick="document.getElementById('id01').style.display='block'" class="w3-btn">Register</button></p>
</div>

<div class="w3-container"> 
<h2>Class Registration</h2>

<p>
<input class="w3-input" type="text" name="first" style="width:90%" required>
<label>First Name</label></p>

<p>
<input class="w3-radio" type="radio" name="gender" value="female">
<label>Female</label></p>

<p>
<input class="w3-radio" type="radio" name="gender" value="" disabled>
<label>Don't know (Disabled)</label></p>

<p>
<button class="w3-btn w3-ripple w3-hover-green">Register</button></p>
</div>

</form>

</body>
</html>

​x
 
<!DOCTYPE html><html><title>W3.CSS</title><meta name="viewport" content="width=device-width, initial-scale=1"><link rel="stylesheet" href="https://www.w3schools.com/w3css/5/w3.css"><body>​<img src="img_sailboat.jpg" alt="Boat" class="w3-animate-opacity" style="width:100%;min-height:200px;max-height:400px;">​<div class="w3-container">  <h2>Welcome to Sailing</h2>  <p>Sailing comprises wind propulsion of a craft by means of sails and steering it over water,  ice or land, depending on the type of craft. A sailor manages the force of the wind on the  sails by adjusting their angle with respect to the moving sailing craft...</p>  <p>  <button onclick="document.getElementById('id01').style.display='block'" class="w3-btn">Register</button></p></div>​​<form id="id01" action="/action_page.php" class="w3-modal w3-pale-yellow">​<button onclick="document.getElementById('id01').style.display='none'"class="w3-btn w3-right w3-large w3-hover-red w3-clear">X</button>​<div class="w3-clear"></div>​<div class="w3-container"> <h2>Class Registration</h2>​<p><input class="w3-input" type="text" name="first" style="width:90%" required><label>First Name</label></p>​<p><input class="w3-input" type="text" name="last" style="width:90%" required><label>Last Name</label></p>​<p><input class="w3-radio" type="radio" name="gender" value="male" checked><label>Male</label></p>​