Latest update breaks custom code

I have the following code in my “Custom CCS” box to give the top menu a thicker font:

#header { background-color:transparent!important; }#menu-home {font-weight:bold!important;}

When I applied the most recent update to the theme, that code apparently was broken, because the font went back to being almost unreadably thin.

I went back to the previous version of the theme. Should I wait for a future update, or is there better code I can use?

Thanks for any help.