Sitenav

<header class="c-nav-site">
    <div class="o-flex-container">
        <h1 class="c-nav-site__title"><a href="#"">Site name</a></h1>
    <div class=" c-nav-site__right c-menu">
                <nav class="c-menu__nav" aria-expanded="false">
                    <ul class="c-menu__list c-menu--site">
                        <li class="c-menu__item"><a href="https://www.sciencemuseumgroup.org.uk/">A single link</a></li>
                        <li class="c-menu__item c-menu__item--has-children" aria-haspopup="true">
                            <a href="https://www.sciencemuseumgroup.org.uk/">Another link</a>
                            <button aria-expanded="false" class="c-menu__toggle">
                                <span class="screen-readers">Expand child
                                    menu</span>
                            </button>
                            <ul class="c-menu__submenu" aria-expanded="false">
                                <li class="c-menu__item"><a href="https://www.sciencemuseumgroup.org.uk/">A child link with a long title that wraps</a></li>
                                <li class="c-menu__item"><a href="https://www.sciencemuseumgroup.org.uk/">Another child link</a></li>
                                <li class="c-menu__item"><a href="https://www.sciencemuseumgroup.org.uk/">Another child link</a></li>
                            </ul>
                        </li>
                        <li class="c-menu__item"><a href="https://www.sciencemuseumgroup.org.uk/">A single link</a></li>
                    </ul>

                </nav>
                <div class="c-searchmenu">
                    <div class="c-searchmenu__menuitem">
                        <a href="#js-searchmenu__panel">
                            <svg role="img" aria-labelledby="search1" class="u-icon" tabindex="-1" focusable="false">
                                <title id="search1">Open search</title>
                                <use xlink:href="../../assets/icons/sprite.symbol.svg#search" />
                            </svg>
                        </a>
                    </div>
                    <div class="c-searchmenu__target" id="js-searchmenu__panel"></div>
                    <div class="c-searchmenu__panel">
                        <form method="get" class="c-searchmenu__form" action="search" autocomplete="off">
                            <label for="js-searchmenu--input" class="u-visually-hidden">Search for:</label>
                            <input type="search" id="js-searchmenu--input" class="c-searchmenu__input" placeholder="Search …" value="" name="s" />
                            <button type="submit" class="c-searchmenu__submit">
                                <svg role="img" aria-labelledby="search2" class="u-icon" tabindex="-1" focusable="false">
                                    <title id="search2">Submit search query</title>
                                    <use xlink:href="../../assets/icons/sprite.symbol.svg#search" />
                                </svg>
                            </button>
                        </form>
                    </div>
                    <div class="c-searchmenu__menuitem c-searchmenu__menuitem--close">
                        <a href="#elsewhere">
                            <svg role="img" aria-labelledby="close" class="u-icon">
                                <title id="close">Close search</title>
                                <use xlink:href="../../assets/icons/sprite.symbol.svg#dismiss" />
                            </svg>
                        </a>
                    </div>
                </div>
    </div>

    </div>
    </div>
</header>