What are some common HTML/CSS adjustments that can improve the appearance of a login form in PHP?

When working with a login form in PHP, it's important to pay attention to the HTML and CSS design to ensure a user-friendly and visually appealing interface. Some common adjustments that can improve the appearance of a login form include adding padding and margins to elements, styling the form fields and buttons, and using colors and fonts to make the form visually appealing.

<!DOCTYPE html>
<html>
<head>
    <title>Login Form</title>
    <style>
        body {
            font-family: Arial, sans-serif;
            background-color: #f4f4f4;
        }
        .login-form {
            max-width: 400px;
            margin: 50px auto;
            padding: 20px;
            background-color: #fff;
            border-radius: 5px;
            box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
        }
        input[type="text"],
        input[type="password"],
        button {
            width: 100%;
            padding: 10px;
            margin: 5px 0;
            border: 1px solid #ccc;
            border-radius: 5px;
            box-sizing: border-box;
        }
        button {
            background-color: #007bff;
            color: #fff;
            cursor: pointer;
        }
    </style>
</head>
<body>
    <div class="login-form">
        <h2>Login</h2>
        <form method="post" action="login.php">
            <input type="text" name="username" placeholder="Username" required>
            <input type="password" name="password" placeholder="Password" required>
            <button type="submit">Login</button>
        </form>
    </div>
</body>
</html>