Problema con Firefox 57 (Quantum) -- Problem with Firefox 57 (Quantum)

Hi. A few days ago I’m having problems with Firefox 57, the letters disappear in certain pages, I reinstalled it and nothing happens. The characters are but can not be seen. I was installing Windows XP, 7 and new Google fonts. An image watch more than a thousand words.

Hola. Hace pocos días estoy teniendo problemas con Firefox 57, desaparecen las letras en ciertas paginas, ya lo reinstale y no pasa nada. Los caracteres estan pero no se ven. Estuve instalando fuentes de Windows XP, 7 y nuevas de Google. Una imagen vele mas que mil palabras.

This page with dark theme

Greetings and thanks in advance
Saludos y gracias por adelantado

Ask Ubuntu, where you already posted this question, is a proper place to ask for support. This site, however, is not intended for user support.

I’ve moved this to the category because this site isn’t designed to take tech support questions. Sorry. I’d recommend using one of the official support channels listed on the page.