Override font style in Zabbix frontend

In file:

vi /usr/share/zabbix/include/page_header.php

Find section:

<body lang="<?= CWebUser::getLang() ?>">

Insert before:

<link href="https://fonts.googleapis.com/css?family=Lato&display=swap" rel="stylesheet">
<style>
* {font-family: 'Lato', sans-serif !important;}
</style>

Related:
https://fonts.google.com/specimen/Lato?selection.family=Lato