Footer column sizes

I am trying to change the footer column sizes using the following css. I have it in the custom.css file, but am not getting any love.

#footer .flex_column .av_one_fifth .first {
width: 15%;
}
#footer .flex_column.av_one_fifth:nth-child(2) {
width: 14%;
margin-left: 1%;
}
#footer .flex_column.av_one_fifth:nth-child(3) {
width: 14%;
margin-left: 1%;
}
#footer .flex_column.av_one_fifth:nth-child(4) {
width: 20%;
margin-left: 1%;
}
#footer .flex_column.av_one_fifth:nth-child(5) {
width: 33%;
margin-left: 1%;
}