Login Form created by Andrew Daniels

<?php
session_start();

$conn = mysqli_connect("localhost", "root", "", "members");

if(!$conn) {
    die("Oops! Something went wrong. Please try again later...");
}

$error = false;
if($_SERVER["REQUEST_METHOD"] == "POST") {
    if(empty($_POST["username"])) {
        $error = true;
        echo "<h2 style='color:red; font-family:bold;'>Please enter your Username!</h2>";
    } else {
        $error = false;
    }

    if(empty($_POST["password"])) {
        $error = true;
        echo "<h2 style='color:red; font-family:bold;'>Please enter your Password!</h2>";
    } else {
        $error = false;
    }

    if(!$error && $_POST["username"] != "" && $_POST["password"] != "") {
        $pass = trim($_POST["password"]);
        $pass = strip_tags($pass);
        $pass = htmlspecialchars($pass);

        $password = hash("sha256", $pass);

        $username = trim($_POST["username"]);
        $username = strip_tags($username);
        $username = htmlspecialchars($username);

        $sql = "SELECT * FROM users WHERE username = '$username'";

        $result = mysqli_query($conn, $sql);

        $row = mysqli_fetch_array($result);

        $rowcount = mysqli_num_rows($result);

        if ($rowcount == 1 && $password == $row["password"]) {
            $_SESSION["id"] = $row["id"];
            $_SESSION["username"];

            header("location: home.php");
        }
    }
}
?>

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF=8"/>
    <meta name="viewport" content="width=device-width"/>
    <title>Login System</title>
    <link href="loginstyles.css"/>
</head>
<body>
    <form action="<?php echo htmlspecialchars($_SERVER['PHP_SELF']); ?>">
        <span id="loginHeader">Login</span>
        <br><br>
        <input type="text" name="username" placeholder="Username"/>
        <br>
        <input type="password" name="password" placeholder="Password"/>
        <br>
        <button type="submit" name="submit" class="btn-primary">Login</button>
    </form>
</body>
</html>