HTML & CSS - navigation bar won't float horizontally using float left

Trying to make a navigation bar horizontal with the logo on the left but the text won't move. Anybody got any idea why not?

http://ift.tt/2aMVmAs

CSS

body {
    width 100%;
    max-width: 960px;
    margin: 0 auto;
}

nav {
    width: 100%;
    margin: 20px 0;
}

nav ul {
    width: 100%;
    list-style: none;
    margin: 0;
    padding: 0;
}

nav ul li {
    width: 20%;
    float: left;

}

nav ul li a {
    display: block;
    width: 100%;
}