CSS does not appear to be working.

for some reason my CSS isn't working for the current task. It appears to be working for all the nav stuff I've entered, but not a simple margin change. Since I'm having to use a local host for this course here's the sidebar.php code:

``<div class="col-md-3 sidebar">

<?php if ( ! dynamic_sidebar ( 'page' ) ): ?>

    <h3>Sidebar Setup</h3>
    <p>Please add widgets to the page sidebar in order to have them display here.</p>

<?php endif; ?>

</div>``

Here's the CSS code. I'm including all of it, since there might be a problem with the coding someplace earlier in my page. This is the styl.css page:

`` /* Theme Name: bootstraptowp Author: Sadaajit Ananda Author URI: http://sadaajit.com Description: Example theme for Treehouse course on how to convert static Bootstrap site into dynamic WordPress theme Version: 1.0 License: GNU General Public License v2 or later License URI: http://www.gnu.org/licenses/gpl-2.0.html Text Domain: bootstrap-to-wp

This theme, like WordPress, is licensed under the GPL. Use it to make something cool, have fun, and share what you've learned with others. */

body { padding-top: 50px; padding-bottom: 20px; }

.admin-bar .navbar-fixed-top { margin-top: 30px; }

@media (min-width:768px) { .sub-menu { display: none; position: absolute; background: #222; padding: 10px 15px; width: 200px;
}

li:hover .sub-menu {
    display: block;
}

}

.sub-menu li { margin-bottom: 10px; list-style: none; }

.sub-menu li:last-child { margin-bottom: 0; }

.sub-menu a { color: #999; text-decoration: none; }

.sub-menu a:hover { color: #fff;
}

.current-menu-item > a, .current-menu-parent > a { background: #000;
} .current-menu-parent li a { background: inherit; } .current-menu-parent .current-menu-item a { color: #fff; font-weight: bold; }

.sidebar { margin-top: 40px; }``