Trying to change footer border

Hello all,
I am trying to change the color of my footer border as you see in this image. direct link to my website is mexicostages.nl.

I tried to copy the following code from the stylesheet of my parent theme which is twentyfourteen to my child theme. I tried this but it isn’t working.

#supplementary + .site-info {
	border-top: 12px solid rgba(255, 255, 255, 0.2) !important;
}

I hope someone can help me out ??