aMember (site.php): enable admin theme

site.php

<?php

Am_Di::getInstance()->viewPath = array_merge(
    Am_Di::getInstance()->viewPath,
    [APPLICATION_PATH . '/default/themes-admin/yourtheme']
);
$view = Am_Di::getInstance()->view;
$css = $view->_scriptCss('theme.css');
$view->placeholder('head-finish-admin')->append(<<<CUT
<link href="{$css}" media="screen" rel="stylesheet" type="text/css" >
CUT
);