:root{
    --bg:#0f1115; --panel:#161a21; --panel2:#1c212b; --border:#262c38;
    --text:#e7ebf3; --muted:#8a93a6; --accent:#3d8bfd; --accent2:#2fd18c;
    --danger:#ff5470; --warn:#ffb454; --radius:10px;
  }
  *{box-sizing:border-box}
  body{margin:0;background:var(--bg);color:var(--text);font-family:'Segoe UI',system-ui,-apple-system,sans-serif;font-size:14px}
  header{display:flex;align-items:center;justify-content:space-between;padding:14px 22px;border-bottom:1px solid var(--border);background:var(--panel)}
  header h1{font-size:16px;margin:0;font-weight:600;letter-spacing:.3px}
  header h1 span{color:var(--accent)}
  #session-info{font-size:12px;color:var(--muted)}
  #session-info b{color:var(--text)}
  .layout{display:flex;min-height:calc(100vh - 53px)}
  nav{width:220px;border-right:1px solid var(--border);background:var(--panel);padding:14px 0;flex-shrink:0}
  nav button{display:flex;align-items:center;gap:8px;width:100%;text-align:left;padding:10px 20px;background:none;border:none;color:var(--muted);cursor:pointer;font-size:13.5px}
  nav button:hover{color:var(--text);background:var(--panel2)}
  nav button.active{color:var(--text);background:var(--panel2);border-left:3px solid var(--accent);font-weight:600}
  .nav-group-header{justify-content:space-between;color:var(--text);font-weight:600;text-transform:uppercase;font-size:11.5px;letter-spacing:.5px;margin-top:6px}
  .nav-group-header .chev{transition:transform .15s;color:var(--muted)}
  .nav-group-header.open .chev{transform:rotate(90deg)}
  .nav-submenu{max-height:0;overflow:hidden;transition:max-height .18s ease}
  .nav-submenu.open{max-height:300px}
  .nav-submenu button{padding-left:34px;font-size:13px}
  main{flex:1;padding:22px;overflow-x:auto}
  .view{display:none}
  .view.active{display:block}
  .card{background:var(--panel);border:1px solid var(--border);border-radius:var(--radius);padding:18px;margin-bottom:18px}
  .card h2{margin:0 0 14px;font-size:15px;color:var(--text)}
  .card h3{margin:0 0 10px;font-size:13px;color:var(--muted);text-transform:uppercase;letter-spacing:.5px}
  .row{display:flex;gap:10px;flex-wrap:wrap;align-items:center}
  input[type=text],input[type=password],select{background:var(--panel2);border:1px solid var(--border);color:var(--text);padding:8px 10px;border-radius:6px;font-size:13px}
  input:focus,select:focus{outline:1px solid var(--accent)}
  button.btn{background:var(--accent);color:#fff;border:none;padding:8px 14px;border-radius:6px;cursor:pointer;font-size:13px;font-weight:600}
  button.btn:hover{opacity:.9}
  button.btn.secondary{background:var(--panel2);border:1px solid var(--border);color:var(--text)}
  button.btn.danger{background:var(--danger)}
  button.btn.success{background:var(--accent2);color:#062}
  button.btn:disabled{opacity:.4;cursor:not-allowed}
  table{border-collapse:collapse;width:100%;font-size:12.5px}
  table.table-fit{width:auto;min-width:0}
  table.table-fit th, table.table-fit td{padding:6px 12px;white-space:nowrap;width:1%}
  th,td{padding:7px 10px;border-bottom:1px solid var(--border);text-align:left;white-space:nowrap}
  th{color:var(--muted);font-weight:600;position:sticky;top:0;background:var(--panel)}
  tr:hover td{background:var(--panel2)}
  .tag{display:inline-block;padding:2px 8px;border-radius:20px;font-size:11px;font-weight:700}
  .tag.on{background:rgba(47,209,140,.15);color:var(--accent2)}
  .tag.off{background:rgba(255,84,112,.15);color:var(--danger)}
  .tag.warn{background:rgba(255,180,84,.15);color:var(--warn)}
  .muted{color:var(--muted)}
  .accounts-list{display:flex;flex-direction:column;gap:6px;margin-bottom:12px}
  .acc-item{display:flex;justify-content:space-between;align-items:center;background:var(--panel2);border:1px solid var(--border);border-radius:8px;padding:10px 14px}
  .acc-item:hover{border-color:var(--accent)}
  #log-panel{position:fixed;bottom:0;left:0;right:0;height:150px;background:#0a0c10;border-top:1px solid var(--border);font-family:Consolas,monospace;font-size:11.5px;overflow-y:auto;padding:8px 14px;display:none;z-index:50}
  #log-panel.show{display:block}
  body.log-open .layout{padding-bottom:var(--log-h, 180px)}
  .log-line{padding:1px 0;white-space:pre-wrap}
  .log-line.err{color:var(--danger)}
  .log-line.ok{color:var(--accent2)}
  .log-line.warn{color:var(--warn)}
  #log-toggle{position:fixed;bottom:10px;right:16px;z-index:60}
  .modal-backdrop{position:fixed;inset:0;background:rgba(0,0,0,.55);display:none;align-items:center;justify-content:center;z-index:100}
  .modal-backdrop.show{display:flex}
  .modal{background:var(--panel);border:1px solid var(--border);border-radius:var(--radius);padding:20px;width:340px}
  .modal h3{margin-top:0}
  .modal .row{margin-top:12px}
  .banner{background:rgba(255,180,84,.1);border:1px solid var(--warn);color:var(--warn);padding:10px 14px;border-radius:8px;font-size:12.5px;margin-bottom:16px}
  .checklist{max-height:260px;overflow-y:auto;border:1px solid var(--border);border-radius:8px;padding:8px}
  .checklist label{display:flex;gap:8px;align-items:center;padding:5px 4px;font-size:13px}
  small.hint{color:var(--muted);display:block;margin-top:4px}
  .stat-grid{display:flex;gap:14px;flex-wrap:wrap}
  .stat-box{background:var(--panel2);border:1px solid var(--border);border-radius:8px;padding:14px 20px;min-width:140px}
  .stat-box .num{font-size:22px;font-weight:700;color:var(--accent)}
  .stat-box .lbl{font-size:11.5px;color:var(--muted);text-transform:uppercase;letter-spacing:.4px}

  /* ---- Responsive: hamburger + nav drawer (không phụ thuộc chọn thiết bị, dựa hoàn toàn vào viewport width) ---- */
  #nav-hamburger{display:none;background:none;border:1px solid var(--border);color:var(--text);border-radius:6px;padding:6px 10px;font-size:16px;cursor:pointer;line-height:1}
  #nav-close{display:none}
  #nav-backdrop{position:fixed;inset:0;background:rgba(0,0,0,.55);z-index:150;display:none}
  #nav-backdrop.show{display:block}

  @media (max-width:860px){
    #nav-hamburger{display:inline-flex;align-items:center}
    header h1 small{display:none}
    header h1{font-size:14.5px}
    nav{
      position:fixed; top:0; left:-280px; bottom:0; width:260px; z-index:200;
      transition:left .22s ease; box-shadow:2px 0 18px rgba(0,0,0,.4); overflow-y:auto;
      padding-top:8px;
    }
    nav.open{left:0}
    #nav-close{
      display:flex; align-items:center; justify-content:space-between; width:100%;
      padding:10px 16px 14px; color:var(--text); font-weight:700; font-size:13.5px;
      background:none; border:none; border-bottom:1px solid var(--border); margin-bottom:6px; cursor:pointer;
    }
    .layout{display:block}
    main{width:100%}
  }
  @media (max-width:480px){
    body{font-size:13px}
    header{padding:10px 14px}
    header h1{font-size:13px}
    main{padding:14px}
    .card{padding:14px}
    .card h2{font-size:13.5px}
    .stat-grid{display:grid;grid-template-columns:1fr 1fr;gap:10px}
    .stat-box{min-width:0;padding:10px 12px}
    .stat-box .num{font-size:18px}
    button.btn, button.btn.secondary, button.btn.danger{padding:7px 10px;font-size:12.5px}
    th,td{padding:5px 7px;font-size:11.5px}
    input[type=text],input[type=password],select{padding:7px 8px;font-size:12.5px}
  }