Drop down width same as parent

Question

I'm creating a drop down menu, the top level list item will display a username.

I have a bit of an issue because I want the dropdown menu to be the same width at the top level list item being hovered over.

However, if I set ul li ul li to width 100%, it takes 100% of the overall container, not of the ul above it. I think because ul ul's are position absolute?

Any ideas how I can make the drop down menu's the same width as the parent list item?

The page can be seen here.

and here's the HTML

<ul>
    <li><a href="#"><span aria-hidden="true" data-icon="a"> A long name here</a>
    <ul>
        <li><a href="#">View Profile</a></li>
        <li><a href="#">Edit Profile</a></li>
        <li><a href="#">Settings</a></li>
        <li><a href="#">My Payments</a></li>
    </ul>
    </li>

    <li><a href=""> <span aria-hidden="true" data-icon="c"> Online</a></li>
    <li><a href="#"> Log Out</a></li>

</ul>

CSS

.head-link ul ul {
    display: none;
}

.head-link ul li:hover > ul {
    display: block;
}

.head-link ul {  
    list-style: none;
    position: relative;
    display: inline-table;
}

    .head-link ul li {
    float: left;
    border-top-left-radius: 0.5em;
    border-top-right-radius: 0.5em;
    height: 2em;
    width: auto;
    padding: 0.5em 0.98em;
}

.head-link ul li:hover {
    background: #ffffff;
}

.head-link ul li:hover a {
    color: #434343;
    border-bottom: none;
}

.head-link ul li a {
    display: block; 
    color: #ffffff; 
    text-decoration: none;
}

.head-link ul ul {
    background: #ffffff; 
    border-radius: 0px; 
    padding: 0;
    position: absolute; 
    top: 99%;
    left: 0;
    text-align: left;
    border-bottom-left-radius: 0.5em;
    border-bottom-right-radius: 0.5em;
    padding-bottom: 0.8em;
    padding-top: 0.5em;
    box-shadow: 0px 0.3em 0.4em rgba(0,0,0,0.3);
}

.head-link ul ul li {
    float: none; 
    position: relative;
    padding: 0em;
}

.head-link ul ul li a {
    padding: 0.5em 1.24em;
    color: #434343;
    border-bottom-left-radius: 0.5em;
    border-bottom-right-radius: 0.5em;
}   

.head-link ul ul li a:hover {
    background: #ffffff;
    text-decoration: underline;
}

.head-link ul ul ul {
    position: absolute; 
    left: 100%; 
    top:0;
}

Solution

Here's how I made it look like this:

Just modify these rules:

.head-link ul li {
    position: relative;
    ... /* Keep all current rules */
}
.head-link ul li ul {
    width: 100%;
    ... /* Keep all current rules */
}