oliverdavies.uk/source/_partials/pages/book/signup-form.html.twig

<div id="mc_embed_signup">
    <form action="{{ page.mailchimp_url }}" method="POST" id="mc-embedded-subscribe-form" name="mc-embedded-subscribe-form" class="validate p-0" target="_blank" novalidate>
        <div id="mc_embed_signup_scroll" class="flex">
            <div class="mc-field-group w-full lg:w-1/2 pb-3_ font-bold">
                <label for="mce-EMAIL" class="visuallyhidden">Email Address (required></label>
                <input
                    type="email"
                    value=""
                    name="EMAIL"
                    class="required email block w-full border border-grey p-3 pl-5 rounded-l-full"
                    id="mce-EMAIL"
                    style="text-indent: 0"
                    placeholder="me@example.com"
                >
            </div>

            <div id="mce-responses" class="clear p-0 m-0">
                <div class="response hidden p-0" id="mce-error-response"></div>
                <div class="response hidden p-0" id="mce-success-response"></div>
            </div>

            <div style="position: absolute; left: -5000px;" aria-hidden="true"><input type="text" name="b_b4ac8dd177796d37b93f9c285_033c84e0d5" tabindex="-1" value=""></div>

            <button type="submit" value="Subscribe" name="subscribe" id="mc-embedded-subscribe" class="button is-blue border-0 pl-4 pr-5 py-3 m-0 rounded-r-full">
                Subscribe
            </button>
        </div>
    </form>
</div>