Hi,
sorry you have right, try with this code:
#jsn-form.flat > ul.z-tabs-nav > li > a{
background-color:#e2001a; /* Normal Color */
}
#jsn-form.flat > ul.z-tabs-nav > li:hover > a{
background-color:#e2001a; /* Hover color */
}
#jsn-form.flat > ul.z-tabs-nav > li.z-active > a{
background-color:#e2001a; /* Active color */
}