Menu: colour differences among devices

I need you help please. In my blog on little devices as iphone 5, the twenty twelve responsive theme create a button coloured differently by the one chosen in the style.css child theme. I’d like to have it #080882 but really is light grey.

Can you please tell me how is it possible to change it?

Actually the part of the style.css file I’m looking at is:

.menu-toggle, input[type=”submit”], input[type=”button”], input[type=”reset”], article.post-password-required input[type=”submit”], .bypostauthor cite span {
background-color: #080882;
background-image: -moz-linear-gradient(center top , #080882, #080882);
background-repeat: repeat-x;
border: medium none;
border-radius: 3px;
box-shadow: 0 1px 2px rgba(64, 64, 64, 0.1);
color: #fff;
font-size: 0.785714rem;
font-weight: normal;
line-height: 1.42857;
padding: 0.428571rem 0.714286rem;
}
.menu-toggleL:hover, input[type=”submit”]:hover, input[type=”button”]:hover, input[type=”reset”]:hover, article.post-password-required input[type=”submit”]:hover, .bypostauthor cite span :hover{
background-color: #080882;
background-image: -moz-linear-gradient(center top , #080882, #080882);
background-repeat: repeat-x;
border: medium none;
border-radius: 3px;
box-shadow: 0 1px 2px rgba(64, 64, 64, 0.1);
color: #fff;
font-size: 0.785714rem;
font-weight: normal;
line-height: 1.42857;
padding: 0.428571rem 0.714286rem;

Thanks in advance