Apply CSS when in the menu in question

Just add a CSS class and apply it when you click on the element or read the url to find out where it is

An example:

HTML

<div class="menu" data-url="sobre">Sobre a empresa</div>

CSS

.selected {
    color: #aac;
}

jQuery

var url = document.URL.split('/');
// em vez do document.URL pode usar também window.location.href ou window.location.pathname
url = url[url.length - 1] || url[url.length - 2];
console.log(url); // aqui vai dar-lhe o url em que está
$('.menu').each(function () {
    var self = $(this);
    if (self.data('url') == url) {
        self.addClass('selected');
        return;
    }
    self.removeClass('selected');
});

In HTML I've added a " data-field field." This way you can save the name to which you want to react in the element. I also gave them a menu class to facilitate the jQuery selector that will look up these menu elements.

In CSS I created a class called selected with a specific color.

In jQuery I'll first read the URL. I left a redundancy for the url case that ends with / . But otherwise, as shown in your example in a url like www.dominio.com/sobre it will catch sobre . Then I compare all the elements of the menu to know what has data-url="sobre" and this will receive the new class. The others remove the class if they have it from before (unlikely if you change pages).

Note: I should say that this is much cleaner when done server side. In this case just add the right class to the element corresponding to the page that will open. But I presume it will not be possible for you.