Bulma class: .is-transparent

    <nav class="navbar is-transparent">
        <div class="navbar-brand">
            <a class="navbar-item" href="#">
                LOGO
            </a>
            <div class="navbar-burger" data-target="navbarExampleTransparent">
                <span></span>
                <span></span>
                <span></span>
            </div>
        </div>

        <div id="navbarExampleTransparent" class="navbar-menu">
            <div class="navbar-start">
                <a class="navbar-item" href="#">
                Home
                </a>
                <div class="navbar-item has-dropdown is-hoverable">
                    <a class="navbar-link" href="#">
                        More
                    </a>
                    <div class="navbar-dropdown is-boxed">
                        <a class="navbar-item" href="#">
                        Option 1
                        </a>
                        <a class="navbar-item" href="#">
                        Option 2
                        </a>
                        <a class="navbar-item" href="#">
                        Option 3
                        </a>
                        <a class="navbar-item" href="#">
                        Option 4
                        </a>
                    </div>
                </div>
                <a class="navbar-item" href="#">
                    About
                </a>
            </div>
        </div>
    </nav>