Untitled

<?php
session_start();
if( isset($_SESSION['user_id']) ){
    header("Location: /");
}
require 'database.php';
if (!empty($_POST['username']) && !empty($_POST['password'])):
    $records=$conn->prepare('select id, username, password from admin where username = :username');
    $records->bindParam(':username', $_POST['username']);
    $records->execute();
    $results=$records->fetch(PDO::FETCH_ASSOC);
    $message='';

    if(count($results)>0 && password_verify($_POST['password'], $results['password'])){
        $_SESSION['user_id']=$results['id'];
        header("Location: /");
    }else{
        echo 'Sorry, wrong password';
}
endif;
?>
<html>
<head>
    <link href='http://fonts.googleapis.com/css?family=Comfortaa' rel='stylesheet' type='text/css'>
    <title>Admin Login</title>
</head>
<body>
    <?php if(!empty($message)): ?>
    <p><?=$message ?></p>
    <?php endif; ?>
    <h1>Admin Login</h1>
    <form id='login' method='POST' action='login.php'>
    <label>
        Username:
        <input type='text' name='username' placeholder='Enter your usename' id='username' size='20' maxlength='100'>
    </label>
    <br>
    <label>
        Password:
        <input type='text' name='username' placeholder='Enter your password' id='username' size='20' maxlength='100' >
    </label>
    <br>

    <button type='button'>Login</button>
    </form>
    <a href="register.php">Register</a>
    <br/>
    <style type='text/css'>
        form{
            font-family: Verdana;
            width: auto;
            text-align: center;
        }
        label {
            width: 150px;
            font-size: 170%;
            length: 200px;
        }
        body{
            background-color: lightblue;
            text-align: center;
            position: fixed;
                top: 50%;
                left: 50%;
                margin-top: -100px;
                margin-left: -200px;
            height:200px;
            width:400px;
        }

        button{
            padding:10px;
            color:#fff;
            background:#0098cb;
            width:200px;
            margin:20px auto;
            margin-top:0px;
            border:0px;
            border-radius: 3px;
            cursor:pointer;

        }
        input[type='text']{
            height:30px;
            outline:none;
            padding:10px;
            width:200px;
            border-radius: 3px;
            border:1px solid #eee;
            margin:20px auto;
        }
        button:hover{
            background:#00b8eb;
        }

</body>
</html>