You want to restrict access to Admin. Add the code below to function.php

function codeart_block_dashboard_from_non_super_admins()
{
    $actual_link = "http://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";

    if( !is_super_admin() )
        if( strpos($actual_link, 'wp-admin') !== false || strpos($actual_link, 'wp-login.php') !== false )
            if( strpos($actual_link, 'admin-ajax.php') === false && strpos($actual_link, 'wp-login.php?action=logout') === false )
                wp_redirect( get_bloginfo('home') . '/log-in/' );
}
add_action('init', 'codeart_block_dashboard_from_non_super_admins');