How can one customize the design of a login page in PHP to match the overall website design?

To customize the design of a login page in PHP to match the overall website design, you can create a separate CSS file for the login page and link it in the HTML code. This CSS file can contain styles that match the design elements of the rest of the website, such as fonts, colors, and layout. By applying these styles to the login page, you can ensure that it seamlessly integrates with the overall design of the website.

```php
<!DOCTYPE html>
<html>
<head>
  <link rel="stylesheet" type="text/css" href="login_styles.css">
</head>
<body>
  <div class="login-form">
    <h2>Login</h2>
    <form action="login.php" method="post">
      <input type="text" name="username" placeholder="Username">
      <input type="password" name="password" placeholder="Password">
      <button type="submit">Login</button>
    </form>
  </div>
</body>
</html>
```

In the above code snippet, we have linked a CSS file named "login_styles.css" in the head section of the HTML code. This CSS file can contain styles for the login form elements to match the overall website design.