<ul>
  {% for link in site.navigation %}
    {% assign current = nil %}

    {% if page.url contains link.url %}
      {% assign current = 'current' %}
    {% endif %}

    <li class="{% if forloop.first %}first {% endif %}{{ current }}{% if forloop.last %} last{% endif %}">
      <a href="{{ link.url }}">{{ link.title }}</a>
    </li>
  {% endfor %}
</ul>

<ul>
  {% for link in site.navigation %}
    {% assign url = page.url | remove:'/index.html' %}
    <li {% if url == link.url %}class="current"{% endif %}>
      <a href="{{link.url}}" title="{{link.title}}">{{link.title}}</a>
    </li>
  {% endfor %}
</ul>

Fix current page link highlighting
Fix current page link highlighting
