Вроде все подключил правильно, но классы container, container-fluid и другие не работают.
<!DOCTYPE html>
<html>
<head>
<title>HackerSpace</title>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/css/bootstrap.min.css" integrity="sha384-/Y6pD6FV/Vv2HJnA6t+vslU6fwYXjCFtcEpHbNJ0lyAFsXTsjBbfaDjzALeQsN6M" crossorigin="anonymous">
<link rel="stylesheet" href="C:\Users\любовь\Desktop\hack\style.css">
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.11.0/umd/popper.min.js" integrity="sha384-b/U6ypiBEHpOf/4+1nzFpr53nxSS+GLCkfwBdFNTxtclqqenISfwAzpKaMNFNmj4" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/js/bootstrap.min.js" integrity="sha384-h0AbiXch4ZDo7tp9hKZ4TsHbi047NrKGLO3SEJAg45jXxnGIfYzk4Si90RDIqNm1" crossorigin="anonymous"></script>
</head>
<body>
<div class="navbar">
<div class="container">
</div>
<h1 class="text-info">sadkfjsdfjsldkfj</h1>
</div>
<form name="log" method="post" action="login.php">
<div align="center">Login: <input name="login"></input><br>Password: <input name="pass" type="password"></input><br>
Password2: <input name="pass2" type="password"></input><br>
<button type="submit" name="log_in">Sign In</button>
</div>
</form>
</body>
</html>
Простой
Средний
