[HTML] details + summary 태그 사용하기

* 자바 스크립트를 사용하지않고도 드롭박스 메뉴를 구현할 수 있다.

• details > summary^div.list

  <div class="heade_main_log_nav_content head_main_log_nav_profile">
                        <details class="user_item_details">
                            <summary>
                                <div class="user_item_details user_icon">
                                    <img src="../img/user.png" alt="user">
                                </div>
                            </summary>
                            <div class="user_item_details_list details_list_container">
                                <div class="details_list_container_content container_welcome">Welcome !</div>
                                <div class= "details_list_container_content container_MyPage" >Your Page</div>
                                <div class= "details_list_container_content container_Books">Your Books</div>
                                <div class= "details_list_container_content container_Picks">Your Picks</div>
                                <div class= "details_list_container_content container_Signout">Sign out</div>
                            </div>
                        </details>
                    </div>