Why are custom fonts not showing properly?

Custom fonts can be defined with the @font-face CSS rule. An example:

@font-face
{
  font-family: 'Helvetica';
  src: url(https://yourserver.com/fonts/Helvetica.ttf) format('truetype');
  font-weight: normal;
  font-style: normal;
}

body
{
  font-family: Helvetica;
}

The web server serving the font must add the Access-Control-Allow-Origin: * HTTP header to the font response. Use the following links to configure your web server:

• IIS
• Apache
• Nginx