Hi,
font-awesome.min.css is being loaded on your website (on the homepage), not because LightMart, but because of this component:
com_testimonial_pro, So apparently this component loads font-awesome's CSS file only on homepage with this CSS url:
www.araweb.es/components/com_testimonial_pro/css/font-awesome.min.css
LightMArt doesn't load Font-Awesome by default. But you can do it manually by adding the necessary style TAG between <head>.....</head> tag:
<link rel="stylesheet" href="http://www.araweb.es/components/com_testimonial_pro/css/font-awesome.min.css" type="text/css" />
to this PHP file:
/templates/flexible_lightmart/layout/template.php
So, font-awesome will work on all pages
regards.