_includes/header.html

{% comment %}
    Licensed to the Apache Software Foundation (ASF) under one
    or more contributor license agreements.  See the NOTICE file
    distributed with this work for additional information
    regarding copyright ownership.  The ASF licenses this file
    to you under the Apache License, Version 2.0 (the
    "License"); you may not use this file except in compliance
    with the License.  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing,
    software distributed under the License is distributed on an
    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    KIND, either express or implied.  See the License for the
    specific language governing permissions and limitations
    under the License.
{% endcomment %}

{% comment %} capture the current page {% endcomment %}
{% for entry in site.data.navigation %}
    {% capture fullurl %}{{ entry.url | absolute_url }}{% endcapture %}
    {% if fullurl == page.url %}
        {% assign current_page = fullurl %}
        {% break %}
    {% elsif page.url contains fullurl %}
        {% assign current_page = fullurl %}
    {% endif %}
{% endfor %}

<nav class="navbar navbar-expand-lg navbar-light bg-light sticky-top shadow-lg">
    <div class="container d-flex justify-content-between w-100">
            <div class="mr-auto p-2 w-100">
                <div class="d-flex">
                    <a class="navbar-brand mr-auto" href="{% link index.md %}">
                        <img style="max-height: 75px" src="{{ "assets/img/logo/logo_400x160.png" | absolute_url }}"/>
                    </a>
                    <button class="navbar-toggler ml-auto align-self-center" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
                        <span class="navbar-toggler-icon"></span>
                    </button>
                </div>

            </div>

            <div>
                <div class="p-2 collapse navbar-collapse" id="navbarSupportedContent">
                    <div class="navbar-nav">
                        {% for entry in site.data.navigation %}
                        {% if entry.url == current_page %}
                        {% assign current = 'active' %}
                        {% else %}
                        {% assign current = '' %}
                        {% endif %}

                        {% assign sublinks = entry.sublinks %}
                        {% if sublinks %}
                        <li class="nav-item dropdown {{current}}">
                            <a class="nav-link dropdown-toggle" data-toggle="dropdown" href="#" role="button" aria-haspopup="true" aria-expanded="false">
                                {{ entry.title }}
                            </a>
                            <div class="dropdown-menu">
                                {% for sublink in sublinks %}
                                <a class="dropdown-item" href="{{ sublink.url | absolute_url }}">
                                    {{ sublink.title }}
                                </a>
                                {% endfor %}
                            </div>
                        </li>
                        {% else %}
                        <li class="nav-item {{current}}">
                            <a class="nav-link" href="{{ entry.url | absolute_url }}">
                                {{ entry.title }}
                            </a>
                        </li>
                        {% endif %}
                        {% endfor %}
                    </div>
                </div>
            </div>
        </div>
    </div>



</nav>