pure CSS menu, without JavaScript - adopted from http://jsfiddle.net/paullferguson/Sv54G/3/

pure-css-menu.css

html { overflow-y: scroll; }

.tabs {
    position: relative;
    min-height: 100px; /* This part sucks */
    clear: both;
    margin: 25px 0 60px 0;
}
.tab {
    float: left;
}
.tab label {
    background: #eee;
    padding: 10px;
    cursor: pointer;
    width: 90px;
    text-align: center;
    display: block;
    border: 1px solid #ccc;
    margin-left: -1px;
    position: relative;
    left: 1px;
}
.tab label i {
    font-style: normal;
    font-size: 10px;
    color: #aaa;
}
.tab [type=radio] {
    display: none;
}
.content {
    position: absolute;
    top: 40px;
    opacity: 0;
    left: 0;
    background: white;
    right: 0;
    bottom: 0;
    padding: 0px 20px;
    border: 1px solid #ccc;
    height: 0;
    
-webkit-transition: all 400ms cubic-bezier(0.250, 0.460, 0.450, 0.940); 
   -moz-transition: all 400ms cubic-bezier(0.250, 0.460, 0.450, 0.940); 
    -ms-transition: all 400ms cubic-bezier(0.250, 0.460, 0.450, 0.940); 
     -o-transition: all 400ms cubic-bezier(0.250, 0.460, 0.450, 0.940); 
        transition: all 400ms cubic-bezier(0.250, 0.460, 0.450, 0.940);
    
}
[type=radio]:checked ~ label {
    z-index: 2;
}
[type=radio]:checked ~ label ~ .content {
    z-index: 1;
    opacity: 1;
    height: 100%;
    padding: 20px;
}

#close-tab {
    position: absolute;
    z-index: -1;
    top: 0px;
}

#close-tab label {
    background: white;
    border-bottom: 1px solid white;
}

[type=radio]:checked ~ label ~ #close-tab {
    z-index: 3;
}

pure-css-menu.html

<div class="tabs">

    <div class="tab">
        <input type="radio" id="tab-1" name="tab-group-1">
        <label for="tab-1">List 1 <i>&#9660;</i></label>
        <div class="tab" id="close-tab">
            <input type="radio" id="tab-close" name="tab-group-1">
            <label for="tab-close">List 1 <i>&#9650;</i></label>
        </div>

        <div class="content">
            Experemental dropdowns - adding "drop down" and a close button to the "pure CSS tabs" by Chris Coyier - <a href="http://css-tricks.com/13758-functional-css-tabs-revisited/">http://css-tricks.com/13758-functional-css-tabs-revisited/</a>
        </div>
    </div>

    <div class="tab">
        <input type="radio" id="tab-2" name="tab-group-1">
        <label for="tab-2">List 2 <i>&#9660;</i></label>
        <div class="tab" id="close-tab">
            <input type="radio" id="tab-close" name="tab-group-1">
            <label for="tab-close">List 2 <i>&#9650;</i></label>
        </div>

        <div class="content">
            Uses a second radio button within the tab which is grizzly I know but makes it collapsible.
        </div>
    </div>

    <div class="tab">
        <input type="radio" id="tab-3" name="tab-group-1">
        <label for="tab-3">List 3 <i>&#9660;</i></label>
        <div class="tab" id="close-tab">
            <input type="radio" id="tab-close" name="tab-group-1">
            <label for="tab-close">List 3 <i>&#9650;</i></label>
        </div>

        <div class="content">
            Got really excited about getting this working, but sadly IOS crushed the JS free dream :(
        </div>
    </div>

</div>