map $http_user_agent $mathjax_polyfill {
    default "<script type='text/javascript' src='https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML'></script>";
    "~Mozilla.*Firefox/[0-9]+" "";
}

server {
    server_name localhost;
    listen 80 default;
    root /var/www/html;
    index index.html index.htm;

    location / {
        try_files $uri $uri/ =404;
        sub_filter "__X_MATHJAX_POLYFILL_PLACEHOLDER__" $mathjax_polyfill;
    }
}