analytics/lib/plausible_web/templates/site/new_custom_domain.html.eex

<%= form_for @changeset, "/sites/#{URI.encode_www_form(@site.domain)}/custom-domains", [class: "max-w-md w-full mx-auto bg-white dark:bg-gray-800 shadow-md rounded px-8 pt-6 pb-8 mb-4 mt-8"], fn f -> %>
  <h2 class="text-xl font-black dark:text-gray-100">Setup custom domain</h2>
  <div class="my-4 dark:text-gray-100">
    We recommend using a subdomain of the website you're running Plausible on.
    If your site is on <code>example.com</code> you can use <code>stats.example.com</code>.
    <br /><br /> The name of the subdomain can be anything, it doesn't have to be <code>stats</code>.
  </div>
  <div class="my-4">
    <%= label f, :domain, class: "block text-sm font-bold dark:text-gray-100" %>
    <%= text_input f, :domain, class: "transition mt-3 bg-gray-100 dark:bg-gray-900 outline-none appearance-none border border-transparent rounded w-full p-2 text-gray-700 dark:text-gray-300 leading-normal focus:outline-none focus:bg-white dark:focus:bg-gray-800 focus:border-gray-300 dark:focus:border-gray-500", placeholder: "stats.[yourdomain].com" %>
    <%= error_tag f, :domain %>
  </div>

  <%= submit "DNS setup →", class: "button mt-4 w-full dark:text-gray-100" %>
<% end %>