原来所有的navbar-nav>li默认都有一个float: left属性> 元素，这就是为什么它们都向左蜷缩.一旦我添加了下面的代码，它就会使 navbar 居中而不是皱缩起来.

It turns out that there is a float: left property by default on all navbar-nav>li elements, which is why they were all scrunching up to the left. Once I added the code below, it made the navbar both centered and not scrunched up.

.navbar-nav>li {
        float: none;
}

希望这对希望将 navbar 居中的其他人有所帮助.

Hope this helps someone else who's looking to center a navbar.