Adding a Second Tier to this Responsive Drop Down Menu - html

Question

How would I add a second tier to the drop down items?
Below is the code I found on StackOverfow which will work great if I can add
the second tiers.
body {
margin: 0
}
#menuBackground {
background: #2f3036;
width: 100%;
height: 50px;
text-align: center;
}
#menuContainer {
text-align: center;
}
/*Strip the ul of padding and list styling*/
ul {
list-style-type: none;
margin: 0;
padding: 0;
}
/*Create a horizontal list with spacing*/
li {
display: inline-block;
vertical-align: top;
margin-right: 1px;
}
/*Style for menu links*/
li a {
display: block;
min-width: 140px;
height: 50px;
text-align: center;
line-height: 50px;
font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
color: #fff;
background: #2f3036;
text-decoration: none;
font-size: 1rem;
}
/*Hover state for top level links*/
li:hover a {
background: #19c589
}
/*Style for dropdown links*/
li:hover ul a {
background: #f3f3f3;
color: #2f3036;
height: 40px;
line-height: 40px
}
/*Hover state for dropdown links*/
li:hover ul a:hover {
background: #19c589;
color: #fff
}
/*Hide dropdown links until they are needed*/
li ul {
position: absolute;
display: none
}
/*Make dropdown links vertical*/
li ul li {
display: block;
}
/*Prevent text wrapping*/
li ul li a {
width: auto;
min-width: 100px;
padding: 0 20px
}
/*Display the dropdown on hover*/
ul li a:hover+.hidden,
.hidden:hover {
display: block
}
/*Style 'show menu' label button and hide it by default*/
.show-menu {
font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
text-decoration: none;
color: #fff;
background: #19c589;
text-align: center;
padding: 16px 0;
display: none;
width: 100%!important
}
/*Hide checkbox*/
input[type=checkbox] {
display: none
}
/*Show menu when invisible checkbox is checked*/
input[type=checkbox]:checked~#menu {
display: block;
margin: 0 auto
}
/*Responsive Styles*/
#media screen and (max-width: 760px) {
/*Make dropdown links appear inline*/
ul {
position: static;
display: none;
white-space: initial;
}
/*Create vertical spacing*/
li {
margin-bottom: 1px
}
/*Make all menu links full width*/
ul li,
li a {
width: 100%
}
/*Display 'show menu' link*/
.show-menu {
display: block
}
}
<div id="menuBackground">
<div id="menuContainer">
<label for="show-menu" class="show-menu">Show Menu</label>
<input type="checkbox" id="show-menu" role="button">
<ul id="menu">
<li>Home</li>
<li>
About ￬
<ul class="hidden">
<li>Who We Are</li>
<li>What We Do</li>
</ul>
</li>
<li>
Portfolio ￬
<ul class="hidden">
<li>Photography</li>
<li>Web & User Interface Design</li>
<li>Illustration</li>
</ul>
</li>
<li>News</li>
<li>Contact</li>
</ul>
</div>
</div>

Answer 1

To add a tier just open a new ul inside whichever li you want to have the sub section. You can see the example with ul class="hidden.
.hide { display: none }
li:hover { color: red; cursor: pointer; }
li:hover > .hide { display: block }
<ul>
<li>link
<ul class="hide">
<li>sub</li>
</ul>
</li>
<li>deeper link
<ul class="hide">
<li>sub
<ul class="hide">
<li>sub</li>
</ul>
</li>
</ul>
</li>
</ul>