Temp

<script>
    if (/^zh\b/.test(navigator.language)) {
        location.href="/cn.html"
    } else {
        location.href="/en.html"
    }
</script>

# zh-CN is same as zh-Hans-CN but zh-CN is more comman and widely used.
language = "zh-CN"

Zola multi language site setting good reference:
https://github.com/search?q=repo%3Ajustint%2Fpapaya%20lang&type=code