Mobile button menu colour

You need to change this selector:

.navbar .btn-navbar {
    float: right;
    padding: 7px 10px;
    margin-left: 5px;
    margin-right: 5px;
    color: #FFF;
    text-shadow: 0px -1px 0px rgba(0, 0, 0, 0.25);
    background-color: #AB0505;
    background-image: linear-gradient(to bottom, #C80606, #7E0404);
    background-repeat: repeat-x;
    border-color: rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.25);
    box-shadow: 0px 1px 0px rgba(255, 255, 255, 0.1) inset, 0px 1px 0px rgba(255, 255, 255, 0.075);
}

Here is a similar blue button using the blue.css skin:

.btn-primary {
    color: #FFF;
    text-shadow: 0px -1px 0px rgba(0, 0, 0, 0.25);
    background-color: #0074AD;
    background-image: linear-gradient(to bottom, #08C, #005580);
    background-repeat: repeat-x;
    border-color: rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.25);
}

Thank you very much for your help!!
I modified these selectors and now the button is blue.