document.observe("dom:loaded", function() {
  var nav = $('nav');
  nav.addClassName('jsfixed');
  var itemsWidth = 0;
  nav.select('a.level-top span').each(function(s, i){
    // add padding to vertically center
    var paddingTop = ((s.up().getHeight() - s.getHeight()) / 2) + 'px';
    console.log(paddingTop);
    s.setStyle({padding: paddingTop + ' 0 0 0'});
    // calculate total menu item width
    itemsWidth += s.getWidth();
  });
  // manually add padding to make menu fill width
  var topLinks = nav.select('a.level-top');
  var paddingSides = Math.floor((nav.getWidth() - 20 - itemsWidth) / ((topLinks.length * 2) - 2)) + 'px';
  topLinks.each(function(a, i){
    if (i == 0) {
      a.setStyle({padding: '0 ' + paddingSides + ' 0 10px'});
    }
    else if (i == (topLinks.length - 1)) {
      a.setStyle({padding: '0 10px 0 ' + paddingSides});
    }
    else {
      a.setStyle({padding: '0 ' + paddingSides + ' 0 ' + paddingSides});
    }
  });
  
});