I've been learning PHP & HTML the past few days and I've encountered a problem.

When trying to add margin to a `ul` the first item in the `ul` doesn't work.

Here's my style.css & header.php:

**Style.css:**

```
* {
    margin: 0px;
    padding: 0px;
    text-decoration: none;
}

header {
    width: 100%;
    height: 60px;
    background-color: #222222;
}

nav ul {
    float: right;
    margin-top: 450px;
    margin-right: 950px;
}
nav ul li {
    font-size: 25px;
    color: grey;
    float: right;
}
nav ul li a {
    font-family: arial;
    font-size: 20px;
    color: grey;
}

nav ul form {
    font-size: 20px;

}
nav ul form input {
    float: left;
    border: groove;
    margin-right: 6px;
    font-size: 18px;
    text-align: center;
}
nav ul form button {
    float: left;
    margin-left: 74px;
    border: 3px solid grey;
    margin-right: 20px;
    background-color: white;
    color: grey;
    font-size: 25px;
    cursor: pointer;
}

```

**Header.php:**

```
<?php
    session_start();
?>

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Registratie</title>
<link rel="stylesheet" type="text/css" href="style.css">
</head>
<body>

<header>
    <nav>
        <ul>
            <li><a href="index.php">Home</a></li>
            <br>
            <li><a href="signup.php">Sign up</a></li>
            <br>
            <?php
                if (isset($_SESSION['id'])) {
                    echo "<form action='includes/logout.inc.php'>
                        <button>Log out</button>
                        </form>";
                } else {
                    echo "<form action='includes/login.inc.php' method='POST'>
                        <input type='text' name='uid' placeholder='Username'><br>
                        <input type='password' name='pwd' placeholder='Password'><br><br><br>
                        <button type='submit'>Log in</button>
                        </form>";
                }
            ?>
        </ul>
    </nav>
</header>

```

[Here's an image to show what I mean](https://i.stack.imgur.com/Y9vfi.png)