#nav_menu ul {
            list-style-type: none;
            position: relative;
            border-top: 2px solid black;
            border-bottom: 2px solid black;
            margin: 0;
            padding: 0;  
            display: flex;
            justify-content: space-between;
            }

        #nav_menu ul li {
              float: left;
            }

        #nav_menu ul li a {
            text-align: center;
            display: block;
            padding: .5em .5em;
            text-decoration: none;
            font-weight: bold; 
            }

        #nav_menu ul li a.current {
            text-decoration: none; 
            }

        #nav_menu ul ul {
            display: none;
            position: absolute;
            padding: .5em 0; 
            top: 100%; 
            background-color: yellow;
            }

        #nav_menu ul ul li {
            float: none; 
            position: relative;
            padding: 0;
            margin: 0; 
            }

        #nav_menu ul li:hover > ul {
            display: block; 
            padding: 0 .5em ;
            text-align: left; 
            margin-left: 0; 
            }

        #nav_menu ul::after {
            content: "";
            display: block;
            clear: both;
            }

        #nav_menu ul ul li ul {
            position: absolute;
            top: 0;
            left: 100%;
            }

        #nav_menu ul ul li:hover > ul {
            display: block; 
            background-color: pink;
            width: 100%;
            position: absolute;
            text-align: left;
            top: 0; 
            }

        #nav_menu ul li.lastitem ul li:hover > ul {
            position: absolute; 
            left: -100%; 
            }