Centered Header and Menu

<header id="masthead" class="site-header header-wrap" role="banner">
 <div class="container">
  <div class="row">
   <div class="span12">
    <div class="logo site-branding">
    <?php if( isset( $urvr['site-title'] ) && isset( $urvr['custom-logo'] ) && $urvr['site-title'] ) : ?>
     <img src="<?php echo $urvr['custom-logo']['url']; ?>" alt="logo" >
    <?php else : ?>
     <h1 class="site-title"><a href="<?php echo esc_url( home_url( '/' ) ); ?>" rel="home"><?php bloginfo( 'name' ); ?></a></h1>
     <?php if( isset( $urvr['site-description'] ) && $urvr['site-description'] != 0 ) : ?>
      <h2 class="site-description"><?php bloginfo( 'description' ); ?></h2>
     <?php endif; ?>
    <?php endif; ?>
    <?php if( ! isset( $urvr['site-description'] ) ) : ?>
     <h2 class="site-description"><?php bloginfo( 'description' ); ?></h2>
    <?php endif; ?>
   </div> <!-- .logo -->
  </div> <!-- .span12 -->
 </div> <!-- .row -->

 <div class="row">
  <div class="span12">
   <nav id="site-navigation" class="main-navigation" role="navigation">
    <a class="skip-link screen-reader-text" href="#content"><?php _e( 'Skip to content', TEXTDOMAIN ); ?></a>
    <?php wp_nav_menu( array( 'theme_location' => 'primary' ) ); ?>
   </nav> <!-- #site-navigation -->
  </div> <!-- .span12 -->
 </div> <!-- .row -->
 </div> <!-- .container -->
</header><!-- #masthead -->