I tried several fonts and methods and none of them work! The title just appears as a bunch of weapon icons from halflife2.ttf.

ClientTitleFont
{
"1"
{
"name" "impact"
"tall" "32"
"tall_hidef" "46"
"weight" "0"
"additive" "1"
"antialias" "1"
"custom" "1" [$OSX]
}
}
More:
////////////////////// CUSTOM FONT FILES ///////////////////////////
//
// specifies all the custom (non-system) font files that need to be loaded to service the above described fonts
CustomFontFiles
{
"1" "resource/HALFLIFE2.ttf"
"2" "resource/HL2crosshairs.ttf"
"4" "resource/linux_fonts/DejaVuSans.ttf"
"5" "resource/linux_fonts/DejaVuSans-Bold.ttf"
"6" "resource/linux_fonts/DejaVuSans-BoldOblique.ttf"
"7" "resource/linux_fonts/DejaVuSans-Oblique.ttf"
"8" "resource/linux_fonts/LiberationSans-Regular.ttf"
"9" "resource/linux_fonts/LiberationSans-Bold.ttf"
"10" "resource/linux_fonts/LiberationMono-Regular.ttf"
"11" "gamepadui/fonts/din1451alt.ttf"
}

}`