* {
    margin: 0; padding: 0; border: 0; box-sizing: border-box;
}

body {
    background-color: #6B6;
    padding: 20px 80px;
    font-family: verdana;
}

h1 {
    font-weight: normal;
    text-align: center;
    margin: 40px;
    color: white;
}

section.center {
    display: flex;
    justify-content: center;
}

nav#h_menu1 {
    border: 4px solid #456;
}

nav#h_menu1 > ul {
    list-style: none; /* get rid of them bullets */
    /* display: flex; this is a great way to go */
    text-align: center; /* centers children that are text or inline elements */
}

nav#h_menu1 > ul > li {
    border: 4px solid yellow;
    margin: 4px;
    display: inline-block; /* help these blocks behave like inline elements */
    /* the main list item is the parent of the submenu */
    position: relative; /* i want to position the submenu absolute */
}

nav#h_menu1 a {
    border: 0px solid orangered;
    display: block;
    padding: 8px 16px;
    text-decoration: none;
}

nav#h_menu1 a:hover {
    background-color: #FFC;

}

nav#h_menu1 ul.submenu {
    position: absolute;
    top: 100%; left: -8px;
    width: 180px;
    display: none; /* remove the submenu from default view/display */
    padding-top: 10px;
}

nav#h_menu1 > ul > li:hover > ul.submenu {
    display: block;
}

nav#h_menu1 ul.submenu li {
    background-color: darkgreen;
    margin: 4px;
    list-style: none;
}