How to change User Menu to Horizontal

Hi,

How do I change the user menu to horizontal, currently it is displaying as vertical [wcp_menu].

Also, can I target the Title on the WHMCS page <h1>, I have tried
#whmcs_portal .whmcs_portal h1 {
font-size: 13px;
}

but it does not work

also tried
#whmcs_portal h1 {
font-size: 13px;
}
and
.whmcs_portal h1 {
font-size: 13px;
}

and not doing it for me.

Thanks in advance.

Chris