add the codes below into dolphin/inc/design.inc.php Line133
<pre lang="php" line="1">
// Members Only - begin
	if(isMember()) {
		
header( 'Content-type: text/html; charset=utf-8' );
		$echo($oTemplate, 'page_' . $_page['name_index'] . '.html');
	// site url is http://localhost/dolphin/
	} elseif($_SERVER['REQUEST_URI'] == '/dolphin/member.php') {
		header( 'Content-type: text/html; charset=utf-8' );
		$_page_index = $_page['name_index']==150 ? 150: 'login';
		$echo($oTemplate, 'page_' . $_page_index . '.html');
	} else {
		Redirect(BX_DOL_URL_ROOT . 'member.php', array('relocate' => BX_DOL_URL_ROOT . 'index.php'), 'post');
		exit();
	}
// Members Only - end
</pre>
and put a file called page_login.html to the theme folder, so that we could change the style and layout as we like.
<pre lang="xml" line="1">
<bx_include_auto:_header.html />
	__page_main_code__
		<bx_injection:injection_content_after />
		<div class="clear_both"></div>		
		<bx_injection:banner_bottom />
		<bx_injection:injection_between_content_footer />
	__boonex_footers__
<bx_include_auto:_footer.html />
</pre>