Set width: full 320 768 1024 1920 custom
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Simple Newsletter Form</title>
<meta name="description" content="A simple newsletter form with an email address field, GDPR checkbox and a submit button.">
<style>
*, *::before, *::after {
box-sizing: border-box;
}
body {
font-family: Arial, sans-serif;
padding: 10px;
}
.newsletter-form {
max-width: 440px;
margin: 1em auto;
padding: 20px;
border: 1px solid #ddd;
border-radius: 5px;
background: #f4f4f4;
}
.newsletter-form h2 {
margin: 0 0 .75rem 0;
font-size: 1.5em;
}
.newsletter-form p {
margin: 0 0 1em;
font-size: .9em;
}
.newsletter-form details {
margin: 0 0 1em 0;
}
.newsletter-form details summary {
text-decoration: underline;
cursor: pointer;
}
.newsletter-form details div {
margin: .5em 0 1em 0;
}
.newsletter-form details label {
display: block;
cursor: pointer;
}
.newsletter-form>div {
display: flex;
align-items: center;
justify-content: space-between;
margin-top: .85em;
}
.newsletter-form input[type="email"] {
display: block;
width: 100%;
padding: .85em 1em;
border: 1px solid #bbb;
border-radius: 4px;
font-size: 100%;
}
.newsletter-form label{
cursor: pointer;
}
.newsletter-form button[type="submit"] {
padding: .85em 2em;
background: #26d;
color: #fff;
border: none;
border-radius: 4px;
cursor: pointer;
}
.newsletter-form button:hover {
background: #37e;
}
.newsletter-form a {
color: #26d;
}
@media screen and (max-width: 639px) {
.newsletter-form>div {
flex-direction: column;
}
.newsletter-form button[type="submit"] {
margin-top: 1em;
}
}
</style>
</head>
<body>
<form action="" class="newsletter-form">
<h2>Sign up for our newsletter</h2>
<p>Lorem, ipsum dolor sit amet consectetur adipisicing elit. Ut, alias labore magnam illo incidunt sapiente.</p>
<details>
<summary>What can we send you?</summary>
<div>
<label>
<input type="checkbox" checked /> Weekly news
</label>
<label>
<input type="checkbox" checked /> Monthly summary
</label>
<label>
<input type="checkbox" checked /> Important updates
</label>
</div>
</details>
<input type="email" name="email" placeholder="Enter your email address" required>
<div>
<label>
<input type="checkbox" name="agree" required /> I agree to the <a href="#">privacy policy</a>.
</label>
<button type="submit">Subscribe</button>
</div>
</form>
</body>
</html>