Выравнивание кнопки закрытия окна (крестика) по правому краю

let cataloglistbutton=document.querySelector('.catalogbutton');
        let divmenuleft=document.querySelector('.CatalogMenuLeft');
        let divmenusearch=document.querySelector('.CatalogMenuSearch');
        let divmenuright=document.querySelector('.CatalogMenuRight');
        let divfreespace =document.querySelector('.CatalogFreeSpace');
        
        cataloglistbutton.onclick = function () {
            console.log('Before');
            if (document.getElementById('dropdownwindow').style.display=="none")
            {
                document.getElementById('dropdownwindow').style.position="fixed";
                document.getElementById('dropdownwindow').style.marginLeft="0";
                document.getElementById('dropdownwindow').style.marginTop="0";
                document.getElementById('dropdownwindow').style.display="block";
                console.log(document.getElementById('dropdownwindow').style.display);
                document.getElementById('dropdownwindow').style.marginRight="20%";
                document.getElementById('dropdownwindow').style.width="80%";
                /*document.getElementById('dropdownwindowright').style.marginRight="20%";
                document.getElementById('dropdownwindowright').style.marginLeft="20%";              
                document.getElementById('dropdownwindowright').style.width="60%";               
                */
                document.getElementById('dropdownwindowright').style.flex="60%";                
                /*divfreespace.style.width="20%";
                divmenuleft.style.display="block";
                divmenuright.style.display="block";     divmenusearch.style.display="block";
                divfreespace.style.display="block";*/
                document.getElementById('dropdownwindow').style.backgroundColor="#ffffff";
                const menuelems=document.querySelectorAll('.menulistitem');
                menuelems.forEach((menuelem) => { menuelem.addEventListener('mouseover', (event) => { event.target.style.cursor = "pointer";event.target.classList.add('menulistitem_selected')});
                menuelem.addEventListener('mouseout', (event) => { event.target.style.cursor = "pointer"; event.target.classList.remove('menulistitem_selected')});             
                });
                /*const simpleBar = new SimpleBar(document.querySelector('.windowmenulist'));*/
                /*simpleBar.style.visibility="visible";*/
                /*
                document.querySelector('.windowmenulist.simplebar-track.simplebar-vertical').style.visibility="visible";
                document.querySelector('.windowmenulist.simplebar-track.simplebar-vertical.simplebar-scrollbar').style.height="100%";
                document.querySelector('.windowmenulist.simplebar-track.simplebar-vertical.simplebar-scrollbar').style.display="block";
                */
                /*document.getElementById('dropdownwindow').style.position="absolute";*/
                /*document.getElementById('dropdownwindow').style.marginBottom="0px";
                document.getElementById('dropdownwindow').style.paddingBottom="0px";*/              
            } else {
                document.getElementById('dropdownwindow').style.display="none";
                document.getElementById('dropdownwindow').style.position="fixed";
                document.getElementById('dropdownwindow').style.marginLeft="0";
                document.getElementById('dropdownwindow').style.marginTop="0";
                console.log(document.getElementById('dropdownwindow').style.display);
                document.getElementById('dropdownwindow').style.marginRight="0";
                document.getElementById('dropdownwindow').style.width="0";
                /*divfreespace.style.width="0";
                divfreespace.style.marginRight="100%";
                divmenuleft.style.display="none";
                divmenuright.style.display="none";      divmenusearch.style.display="none";
                divfreespace.style.display="none";*/                
                document.getElementById('dropdownwindow').style.backgroundColor="#ffffff";
                /*document.getElementById('dropdownwindow').style.marginBottom="0px";               
                document.getElementById('dropdownwindow').style.paddingBottom="0px";*/
            };          
                
            console.log('After');
        
        }
        
        let closebutton=document.querySelector('.close');
        /*closebutton.style.position="relative";*/
        closebutton.onclick = function () {
                document.getElementById('dropdownwindow').style.display="none";
        }

#dropdownwindow {
    display: none;
    margin-left: 0;
    margin-right: 100%;
    height: 100vh;
    z-index: 5;
}
    
#fullblock {
    height: 100vh;
    position: static;
}

.contentdropdownwindow {
    display: flex;
    /*justify-content: center;*/
}

.CatalogMenuLeft {
    width: 25%;
}

.catalogheader {
    width: 100%;
    height: 30%;
    /*display: flex;*/
    /*justify-content: center;*/
    margin-left: auto;
    margin-right: auto; 
}


.crossline, .bottompart {
    flex: 1;
    /*width: 100%;*/
    /*height: 33%;*/
}

.crosslineright {
    width: 100%;
    margin-top: 40px;
    text-align: right;
}

.windowheader {
    flex: 1;
    /*width: 100%;*/
    /*height: calc(100% - 2*37.5px);*/
    /*height: 34%;*/
    margin: auto;
    text-align: center;
}

.windowheader h4 {
    flex: 1;
    /*width: 100%;*/
    margin: auto;
    text-align: center;
}

.flexdisabledscrollbar1, .flexdisabledscrollbar2, .flexdisabledscrollbar3 {
    flex: 0;
    width: 5px;
    border-right: 5px solid #f5f5f6;    
}

.flexline1 {
    display: flex;
    justify-content: center;
    height: 33%;
}

.flexline2 {
    display: flex;
    justify-content: center;
    height: 34%;
}

.flexline3 {
    display: flex;
    justify-content: center;
    height: 33%;
}

.flexcontent {
    display: flex;
    /*overflow-y: scroll;*/
}

#menulist {
    flex: 1;
    overflow: auto;
    height: 400px;
}

.menulistitem {
    padding-top: 5px;
    padding-bottom: 5px;
}

/* Works on Firefox */

#menulist {
  scrollbar-width: auto;
  scrollbar-color: #b8b8bc #f5f5f6;
  /*overflow-y: scroll;*/
  /*height: 200px;*/
}


/* Works on Chrome, Edge, and Safari */

#menulist::-webkit-scrollbar-button {
    display: none;
}

#menulist::-webkit-scrollbar {
  width: 5px;
}

#menulist::-webkit-scrollbar-track {
  background: #f5f5f6;
}

#menulist::-webkit-scrollbar-thumb {
  background: #b8b8bc;
  border-radius: 2.5px;
  border: 0px solid #f5f5f6;
}

#menulist::-webkit-scrollbar-thumb:hover {
    background: #b8b8bc;
}

.menulistitem_selected {
    font-weight: bold;
    cursor: pointer;
}

.menulistitem_selected::after {
    content: "\2192";
    /*position: absolute;*/
    margin-left: 5px;
    display: inline-block;
    font-weight: 400;
    transition: all .1s ease;
}

.close {
        margin-top: -14px;
        padding-right: 5px;
        padding-left: 5px;
        font-size: 24px;
        cursor: pointer;
        display: inline-block
}

/*
.crossline {
    display: flex;
    justify-content: flex-end;
    align-items: flex-start;
    align-content: flex-start;
}
*/

<div id="dropdownwindow">
        <!-- <div class="crossline">
            <div class="close">&times;</div>
        </div> -->
        <div class="contentdropdownwindow">
            <div class="CatalogMenuLeft">
                    <div class="catalogheader">
                            <div class="flexline1">
                                    <div class="crossline">
                                    </div>
                                    <div class="flexdisabledscrollbar1">
                                    </div>
                            </div>      
                            <div class="flexline2">     
                                    <div class="windowheader">
                                        <h4>Каталог</h4>
                                    </div>
                                    <div class="flexdisabledscrollbar2">
                                    </div>
                            </div>
                            <div class="flexline3">
                                    <div class="bottompart">
                                    </div>
                                    <div class="flexdisabledscrollbar3">
                                    </div>
                            </div>
                    </div>
                            
                        <div class="flexcontent">   
                            <div class="windowmenulist" id="menulist">
                                    <div class="menulistitem">
                                        Смартфоны и гаджеты
                                    </div>
                                    <div class="menulistitem">
                                        Ноутбуки и компьютеры
                                    </div>
                                    <div class="menulistitem">
                                        Телевизоры, аудио-видео, Hi-Fi
                                    </div>
                                    <div class="menulistitem">
                                        Бытовая техника для дома и кухни
                                    </div>
                                    <div class="menulistitem">
                                        Строительство и ремонт
                                    </div>
                                    <div class="menulistitem">
                                        Дом и дача
                                    </div>
                                    <div class="menulistitem">
                                        Фото, видео, системы безопасности
                                    </div>
                                    <div class="menulistitem">
                                        Автотовары
                                    </div>
                                    <div class="menulistitem">
                                        Канцтовары, Мебель и Офисная техника
                                    </div>
                                    <div class="menulistitem">
                                        Красота и здоровье
                                    </div>
                                    <div class="menulistitem">
                                        Спорт и отдых
                                    </div>
                                    <div class="menulistitem">
                                        Товары для геймеров
                                    </div>
                                    <div class="menulistitem">
                                        Уцененные товары
                                    </div>
                                    <div class="menulistitem">
                                        Подарочные сертификаты
                                    </div>
                                    <div class="menulistitem">
                                        Сервисы и услуги
                                    </div>                                  
                            </div>
                            <!--
                            <div class="flexenabledscrollbar">
                        
                            </div>
                            -->
                        </div>
            </div>
            <div class="myscroll">
            
            </div>
            <div id="dropdownwindowright">
                    <div class="crosslineright">
                        <div class="close">&times;</div>
                    </div>
                    <div class="CatalogMenuSearch">
                    </div>
                    <div class="CatalogMenuRight">
                    </div>
            </div>
        </div>
<!--<div>-->        
<!--</div>-->
</div>

<header id="pageHeader">
<!--<div class="headerinsides">
        <a href="#" class="flexcitylink">
                <div class="icon">
                        <svg aria-hidden="true" class="Sg" width="16" height="16" fill="none" xmlns="http://www.w3.org/2000/svg"><path fill-rule="evenodd" clip-rule="evenodd" d="M8.057 8a2.012 2.012 0 01-2.019-2c0-1.103.906-2 2.02-2 1.113 0 2.018.897 2.018 2s-.905 2-2.019 2zm0-5C6.387 3 5.03 4.346 5.03 6s1.358 3 3.028 3 3.029-1.346 3.029-3-1.359-3-3.029-3zm0 11.777C6.852 13.5 3.01 9.177 3.01 6c0-2.757 2.264-5 5.047-5 2.784 0 5.047 2.243 5.047 5 0 3.174-3.841 7.5-5.047 8.777zM8.057 0C4.717 0 2 2.691 2 6c0 4.159 5.468 9.623 5.7 9.854a.509.509 0 00.714 0c.233-.23 5.7-5.695 5.7-9.854 0-3.309-2.716-6-6.057-6z" fill="currentColor"></path></svg>
                </div>
                <div class="mainpart">
                 Краснодар
                </div>
        </a>
                <div class="headerparamswrapper">
                <div class="intermediatespace">
                </div>
                <div class="telephonenumber">
                8 (800)6003900 (круглосуточно)
                </div>
                <div class="addressandworkschedule">
                    Адрес и график работы
                </div>
                <div class="payment">
                    Оплата
                </div>
                <div class="delivery">
                    Доставка
                </div>
                </div>
</div>-->
<div class="headerinsides">
        <span class="flexcitylinkwrapper">
        <a href="#" class="flexcitylink">
                <span class="icon">
                        <svg aria-hidden="true" class="Sg" width="16" height="16" fill="none" xmlns="http://www.w3.org/2000/svg"><path fill-rule="evenodd" clip-rule="evenodd" d="M8.057 8a2.012 2.012 0 01-2.019-2c0-1.103.906-2 2.02-2 1.113 0 2.018.897 2.018 2s-.905 2-2.019 2zm0-5C6.387 3 5.03 4.346 5.03 6s1.358 3 3.028 3 3.029-1.346 3.029-3-1.359-3-3.029-3zm0 11.777C6.852 13.5 3.01 9.177 3.01 6c0-2.757 2.264-5 5.047-5 2.784 0 5.047 2.243 5.047 5 0 3.174-3.841 7.5-5.047 8.777zM8.057 0C4.717 0 2 2.691 2 6c0 4.159 5.468 9.623 5.7 9.854a.509.509 0 00.714 0c.233-.23 5.7-5.695 5.7-9.854 0-3.309-2.716-6-6.057-6z" fill="currentColor"></path></svg>
                </span>
                <span class="labelforicon">
                 Краснодар
                </span>
        </a>
        </span>
                <span class="intermediatespace">
                </span>
                <span class="telephonenumber">
                8 (800) 600 3900 (круглосуточно)
                </span>
                <span class="addressandworkschedule">
                    Адрес и график работы
                </span>
                <span class="payment">
                    Оплата
                </span>
                <span class="delivery">
                    Доставка
                </span>     
</div>
<div class="headerinsidessecondrow">
<button class="catalogbutton">Каталог товаров</button>

<span class="betweenspace">
</span>

<span class="findinfo">
        <input placeholder="Поиск среди 10000 товаров" class="inputsearch"></input>
        <button class="searchbutton">Найти</button>
</span>

<span class="secondbetweenspace">
</span>

<span class="loginandsignup">
    <span class="loginsignupimg">
        <img src="../images/header_profile-icon.png">
    </span>
    <span class="loginsignuptext">
        Вход и регистрация
    </span>
</span>

<span class="basket">
    <span class="loginsignupimg">
        <img src="../images/header_cart-icon.png">
    </span>
    <span class="loginsignuptext">
        Корзина
    </span>
</span>
</div>
</header>