Changing menu font

Hello,

I trying to change font in menu via child time style.css.

@font-face {
 font-family: 'Coda-Heavy';
 src: url('Coda-Heavy.ttf');
}

#mainnav-menu a {
font-family: 'Coda-Heavy', Tahoma, Arial;

i have already created folder “fonts” in original theme and child theme and font in.

Any idea how to change font or wha’s wrong. Nice theme! Thanks.

muonlineczech.4fan.cz