<header>
<nav class="navbar navbar-expand-sm navbar-dark" style="background-color: #f72f61;">
        <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#collapsibleNavbar">
            <span class="navbar-toggler-icon"></span>
        </button>
        <div class="collapse navbar-collapse" id="collapsibleNavbar">
            <ul class="navbar-nav mr-auto mt-2 mt-lg-0">
                <li class = "nav-item active"><a class="nav-link" href="/">Home</a></li>   
                <li class = "nav-item"><a class="nav-link" href="/about">O time</a></li>
                <li class = "nav-item"><a class="nav-link" href="/slides">Galeria</a></li>
            </ul>
        </div>
    </nav>
</header>