<!DOCTYPE html>
<html lang="{{ site.lang | default: "en-US" }}">
  <head>
    <meta charset="UTF-8">

{% seo %}
  <script type="text/javascript" async
    src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.7/MathJax.js?config=TeX-MML-AM_CHTML">
  </script>

    <link rel="preconnect" href="https://fonts.gstatic.com">
    <link rel="preload" href="https://fonts.googleapis.com/css?family=Open+Sans:400,700&display=swap" as="style" type="text/css" crossorigin>
    <meta name="viewport" content="width=devic