I need a lightweight age-gate that asks visitors to tick a single “I am 18 or older” checkbox before they can view any content. The script has to drop straight into my current site, which is a static build sitting behind Cloudflare, so please keep dependencies minimal—plain JavaScript, a dash of HTML/CSS and, if useful, a small Cloudflare Worker or Page Rule is fine. When the box is checked and submitted, the page should set a cookie so verified users aren’t prompted again for at least 30 days. If they decline or close the prompt, simply redirect them to an external URL I’ll supply. It should look like what i have uploaded.