(function() {
  var P = [83,101,110,116,105,110,101,108,50,48,50,54,35];
  var AUTH_DAYS = 7, AUTH_KEY = 'sn_auth';

  function isAuthed() {
    try { var o=JSON.parse(localStorage.getItem(AUTH_KEY)); return o&&(Date.now()-o.ts)/864e5<AUTH_DAYS; } catch(e){return false}
  }
  if (isAuthed()) return;

  // 创建全屏遮罩
  var ov = document.createElement('div');
  ov.id = 'sn-auth';
  ov.style.cssText = 'position:fixed;inset:0;z-index:999999;background:#0a0e17;display:flex;align-items:center;justify-content:center';
  ov.innerHTML = '<div style="text-align:center;max-width:360px;padding:40px">'
    + '<div style="font-size:2rem;font-weight:800;letter-spacing:3px;background:linear-gradient(135deg,#00d4ff,#7b61ff);-webkit-background-clip:text;-webkit-text-fill-color:transparent;margin-bottom:8px">SENTINELNET</div>'
    + '<div style="color:#6b7b8d;font-size:0.85rem;margin-bottom:32px">请输入访问密码</div>'
    + '<input id="sn-pwd" type="password" placeholder="访问密码" autocomplete="off" style="width:100%;padding:14px 18px;border-radius:10px;font-size:1rem;border:1px solid rgba(0,212,255,0.2);background:rgba(255,255,255,0.04);color:#c8d6e5;outline:none;box-sizing:border-box">'
    + '<button id="sn-btn" style="width:100%;margin-top:16px;padding:14px;border:none;border-radius:10px;font-size:1rem;font-weight:600;cursor:pointer;color:#fff;background:linear-gradient(135deg,#00d4ff,#7b61ff)">验 证</button>'
    + '<div id="sn-err" style="color:#ff6b9d;font-size:0.82rem;margin-top:12px;display:none">密码错误，请重试</div>'
    + '</div>';

  // 插入遮罩 + 隐藏页面内容
  document.documentElement.appendChild(ov);
  var s = document.createElement('style');
  s.textContent = 'body.sn-lock>*:not(#sn-auth){visibility:hidden!important}';
  document.head.appendChild(s);
  document.body.classList.add('sn-lock');

  var inp = document.getElementById('sn-pwd');
  var btn = document.getElementById('sn-btn');
  var err = document.getElementById('sn-err');

  function check() {
    var v = inp.value;
    var ok = v.length === P.length;
    if (ok) for (var i=0; i<P.length; i++) { if (v.charCodeAt(i) !== P[i]) { ok=false; break; } }
    if (ok) {
      localStorage.setItem(AUTH_KEY, JSON.stringify({ts:Date.now()}));
      document.body.classList.remove('sn-lock');
      ov.remove(); s.remove();
    } else {
      err.style.display = 'block';
      inp.value = '';
      inp.focus();
    }
  }

  btn.onclick = check;
  inp.onkeydown = function(e) { if (e.key==='Enter') check(); };
  setTimeout(function(){ inp.focus(); }, 200);
})();