I noticed that sometimes you use theme's styles and immediately overwrite it with inline styles. It makes the customization pretty challenging. If you declare that you use themes you should keep all styles in the themes css files

Example in main.header.view.php line 16

<a onClick="loadDashboard('<?php echo $page->getDefaultDashboard()?$page->getDefaultDashboard()->name():null; ?>')" href="javascript: void 0" class="navbar-brand text-center" style="color:#fff;background-image:none;padding-top:10px" href="#">
        <?php echo $page->app()->logo(); ?>
    </a>