Php – Loading CSS, JS in CodeIgniter

I am kinda newbie to CodeIgniter. Somehow I set up the development environment and ready to go. But loading the CSS, JS into page seems a lot more confusing. Before moving, I googled a lot but the base_url solution is not helping.

Part of View :

<link href="css/bootstrap-responsive.css" rel="stylesheet">
<link href="css/jquery-ui-1.8.21.custom.css" rel="stylesheet">
<link href='css/fullcalendar.css' rel='stylesheet'>
<link href='css/fullcalendar.print.css' rel='stylesheet'  media='print'>
<link href='css/opa-icons.css' rel='stylesheet'>
<link href='css/uploadify.css' rel='stylesheet'>

Controller :

public function dashboard()
    {
        $this->load->helper('url');
        $this->load->view('templates/css_styles');
        $this->load->view('templates/top_bar');
        $this->load->view('templates/left_menu');
        $this->load->view('pages/dashboard');
        $this->load->view('templates/footer');
        $this->load->view('templates/js_end');
    }
public function index()
    {
        $this->load->helper(array('form'));
        $this->load->view('login');
    }

route.php :

$route['default_controller'] = "welcome/dashboard";
$route['404_override'] = '';
$route['dashboard'] = 'welcome/dashboard';

If I put the dashboard method as default controller, the page is loading fine. But when I change it to just welcome, which is a login form and redirect to welcome/dashboard, the page doesn't load any CSS. Just all HTML texts. The dashboard page is just pure HTML, no PHP code written yet.

Please help me what might causing this.