href="https://ardupilot.org/copter/index.html">ArduCopter</a>
                        <a class="nav-link {% if current_page == 'arducopter' %}active{% endif %}" target="_blank" href="https://docs.px4.io/main/en/index.html">PX4</a>
                        <a class="nav-link {% if current_page == 'arducopter' %}active{% endif %}" target="_blank" href="https://www.ros.org/">ROS</a>
                        <a class="nav-link {% if current_page == 'arducopter' %}active{% endif %}" target="_blank" href="https://d