if (!isset($_COOKIE['human_token']) || $_COOKIE['human_token'] !== 'passed') {
    if (!preg_match('/(yandexbot|googlebot|bingbot|mail\.ru)/i', $_SERVER['HTTP_USER_AGENT'])) {
        ob_start(function($buffer) {
            $captcha_html = '
            <div id="captcha-overlay" style="display:none; position:fixed; top:0; left:0; width:100%; height:100%; background:rgba(0,0,0,0.7); z-index:999999; justify-content:center; align-items:center;">
                <div style="background:#fff; padding:30px; border-radius:12px; box-shadow:0 8px 30px rgba(0,0,0,0.3); text-align:center; width:320px; border-top:4px solid #d6063e; font-family:sans-serif; user-select:none; -webkit-user-select:none;">
                    <h3 style="margin:0 0 8px 0; color:#1e293b; font-size:20px;">Проверка активности</h3>
                    <p style="font-size:13px; color:#64748b; margin:0 0 20px 0;">Передвиньте ползунок вправо,<br>чтобы совместить пазл</p>
                    <div style="position:relative; width:260px; height:140px; background:#f8fafc; border-radius:8px; margin:0 auto 20px auto; border:1px solid #cbd5e1; overflow:hidden;">
                        <div style="position:absolute; top:45px; left:165px; width:50px; height:50px; background:#cbd5e1; border:2px dashed #475569; border-radius:8px; box-sizing:border-box;"></div>
                        <div id="p-piece" style="position:absolute; top:45px; left:0; width:50px; height:50px; background:#d6063e; border:2px solid #fff; border-radius:8px; cursor:grab; box-shadow:0 4px 12px rgba(214,6,62,0.3); box-sizing:border-box; z-index:5;"></div>
                    </div>
                    <div style="position:relative; width:260px; height:44px; background:#f1f5f9; border-radius:6px; margin:0 auto; border:1px solid #cbd5e1;">
                        <div id="p-track" style="position:absolute; top:0; left:0; height:100%; background:#fce7f3; width:0; border-radius:6px; border:1px solid #d6063e; box-sizing:border-box;"></div>
                        <div id="p-thumb" style="position:absolute; top:2px; left:2px; width:38px; height:38px; background:#d6063e; border-radius:4px; cursor:grab; display:flex; align-items:center; justify-content:center; color:#fff; font-weight:bold; z-index:10; font-size:18px;">&rarr;</div>
                    </div>
                </div>
            </div>
            <script>
                setTimeout(() => {
                    document.getElementById("captcha-overlay").style.display = "flex";
                }, 60000);

                const th = document.getElementById("p-thumb"), pc = document.getElementById("p-piece"), tr = document.getElementById("p-track");
                let isD = false, sx = 0;
                
                const start = (e) => { isD = true; sx = e.clientX || e.touches[0].clientX; };
                const move = (e) => {
                    if (!isD) return;
                    const cx = e.clientX || e.touches[0].clientX;
                    let dx = cx - sx;
                    if (dx < 0) dx = 0; if (dx > 210) dx = 210;
                    th.style.left = dx + "px"; pc.style.left = dx + "px"; tr.style.width = (dx + 20) + "px";
                };
                const end = () => {
                    if (!isD) return; isD = false;
                    const finalX = parseInt(th.style.left);
                    if (finalX >= 155 && finalX <= 175) {
                        document.cookie = "human_token=passed; path=/; max-age=86400; SameSite=Lax";
                        document.getElementById("captcha-overlay").style.display = "none";
                        window.location.reload();
                    } else {
                        th.style.left = "2px"; pc.style.left = "0px"; tr.style.width = "0px";
                    }
                };
                
                th.addEventListener("mousedown", start); window.addEventListener("mousemove", move); window.addEventListener("mouseup", end);
                th.addEventListener("touchstart", start); window.addEventListener("touchmove", move); window.addEventListener("touchend", end);
            </script>';

            if (strpos($buffer, '</body>') !== false) {
                return str_replace('</body>', $captcha_html . '</body>', $buffer);
            }
            return $buffer . $captcha_html;
        });
    }
}