Code Challenge Challenged: Inside the media query, select the list items inside the gallery and add a width of 28.3333%.

In this challenge I am having a hard time understanding why it won't accept my code. After following along with the lesson, I add my code (which is below) and it won't accept my answer. Any insight to this problem is much appreciated.

Code:

@media screen and (min-width: 480px) {

/********************************* TWO COLUMN LAYOUT **********************************/

#primary { width: 50%; float: left; }

#secondary { width: 40%; float: right; }

/********************************* PAGE: PORTFOLIO **********************************/

#gallery li { width: 28.3333%; }

#gallery li:nth-child(4n) { clear: left; }

/********************************* PAGE: ABOUT **********************************/

.profile-photo { float: left; margin: 0 5% 80px 0; }

}

@media screen and (min-width: 660px){

/********************************* HEADER **********************************/ nav { background: none; float: right; font-size: 1.125em; margin-right: 5%; text-align: right; width: 45%; }

#logo { float: left; margin-left: 5%; text-align: left; width: 45%; }

h1 { font-size: 2.5em; }

h2 { font-size: 0.825em; margin-bottom: 20px; }

header { border-bottom: 5px solid #599a68; margin-bottom: 60px; }

}