Hello Paula,

Please do take note that our support policy does not include customizations. However, I will help you out just this once,

[gist]
/** Changing the color of the search in frosty **/
body #es .es-toolbar .o-navbar-search .o-navbar-search__query,
body #es .es-toolbar .o-navbar-search {
background: #666;
}

/** Changing the background color of the toolbar in frosty **/
body #es .es-toolbar .navbar-inner,
body #es .es-toolbar .es-toolbar-avatar {
background: #000;
border: 1px solid #000;
}
[/gist]