:root{
    --bg:#0d1420; --panel:#151f2e; --panel2:#1b2940; --border:#263652;
    --text:#dbe6f5; --muted:#7f93b3; --accent:#2f9df4; --green:#2ecc71;
    --yellow:#f4b400; --red:#e74c3c; --sidebar:#0b111c;
  }
  *{margin:0;padding:0;box-sizing:border-box;font-family:"Segoe UI","Helvetica Neue",Arial,sans-serif;}
  body{background:var(--bg);color:var(--text);min-height:100vh;}
  /* ============ Login ============ */
  #loginPage{position:fixed;inset:0;z-index:100;display:flex;align-items:center;justify-content:center;
    background:linear-gradient(135deg,#0d1420 0%,#13233d 50%,#0d1420 100%);}
  #loginPage.hidden{display:none;}
  .login-box{width:380px;background:var(--panel);border:1px solid var(--border);border-radius:14px;padding:40px 36px;box-shadow:0 20px 60px rgba(0,0,0,.5);}
  .login-box h1{font-size:20px;margin-bottom:6px;}
  .login-box .sub{color:var(--muted);font-size:13px;margin-bottom:28px;}
  .login-logo{display:flex;align-items:center;gap:10px;margin-bottom:24px;}
  .login-logo .icon{width:44px;height:44px;border-radius:10px;background:linear-gradient(135deg,#2f9df4,#1a6fc4);display:flex;align-items:center;justify-content:center;font-size:24px;}
  .login-logo .t b{font-size:16px;display:block;line-height:1.3;}
  .login-logo .t span{font-size:12px;color:var(--muted);}
  .form-group{margin-bottom:18px;}
  .form-group label{display:block;font-size:13px;color:var(--muted);margin-bottom:6px;}
  .form-group input,.form-group select{width:100%;padding:10px 12px;background:var(--panel2);border:1px solid var(--border);border-radius:8px;color:var(--text);font-size:14px;outline:none;}
  .form-group input:focus{border-color:var(--accent);}
  .btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;padding:10px 18px;border-radius:8px;border:1px solid var(--border);background:var(--panel2);color:var(--text);font-size:14px;cursor:pointer;transition:.15s;}
  .btn:hover{filter:brightness(1.15);}
  .btn-primary{background:linear-gradient(135deg,#2f9df4,#1a6fc4);border-color:transparent;color:#fff;font-weight:600;}
  .btn-danger{background:#e74c3c;border-color:transparent;color:#fff;}
  .btn-green{background:#2ecc71;border-color:transparent;color:#fff;}
  .btn-sm{padding:6px 12px;font-size:13px;}
  .login-btn{width:100%;padding:12px;font-size:15px;margin-top:6px;}
  .login-hint{margin-top:16px;font-size:12px;color:var(--muted);text-align:center;line-height:1.6;}
  /* ============ App frame ============ */
  #app{display:none;min-height:100vh;}
  #app.visible{display:flex;}
  .sidebar{width:230px;background:var(--sidebar);border-right:1px solid var(--border);min-height:100vh;position:fixed;top:0;bottom:0;left:0;display:flex;flex-direction:column;}
  .sidebar .logo{display:flex;align-items:center;gap:10px;padding:20px 18px;border-bottom:1px solid var(--border);}
  .sidebar .logo .icon{width:36px;height:36px;border-radius:8px;background:linear-gradient(135deg,#2f9df4,#1a6fc4);display:flex;align-items:center;justify-content:center;font-size:19px;}
  .sidebar .logo b{font-size:15px;line-height:1.3;display:block;}
  .sidebar .logo span{display:block;font-size:11px;color:var(--muted);font-weight:400;}
  .nav{padding:12px 10px;flex:1;}
  .nav-item{display:flex;align-items:center;gap:10px;padding:11px 14px;border-radius:8px;color:var(--muted);cursor:pointer;font-size:14px;margin-bottom:4px;}
  .nav-item:hover{background:var(--panel2);color:var(--text);}
  .nav-item.active{background:linear-gradient(90deg,rgba(47,157,244,.18),transparent);color:#fff;border-left:3px solid var(--accent);border-radius:0 8px 8px 0;}
  .sidebar .user{padding:14px 18px;border-top:1px solid var(--border);font-size:13px;color:var(--muted);}
  .main{flex:1;margin-left:230px;min-width:0;}
  .topbar{height:60px;display:flex;align-items:center;justify-content:space-between;padding:0 24px;border-bottom:1px solid var(--border);background:rgba(21,31,46,.7);backdrop-filter:blur(6px);position:sticky;top:0;z-index:50;}
  .topbar h2{font-size:17px;font-weight:600;}
  .topbar .right{display:flex;align-items:center;gap:16px;font-size:13px;color:var(--muted);}
  .status-dot{width:8px;height:8px;border-radius:50%;background:var(--green);display:inline-block;margin-right:5px;box-shadow:0 0 6px var(--green);}
  .content{padding:24px;}
  .page{display:none;}
  .page.active{display:block;}
  /* Cards */
  .cards{display:grid;grid-template-columns:repeat(2,1fr);gap:20px;margin-bottom:20px;}
  @media(max-width:900px){.cards{grid-template-columns:1fr;}}
  .stat-card .value{font-size:44px;}
  .batt{display:flex;align-items:center;gap:8px;margin-top:12px;font-size:12px;color:var(--muted);}
  .batt-bar{flex:1;height:6px;background:var(--panel2);border-radius:4px;overflow:hidden;}
  .batt-bar i{display:block;height:100%;border-radius:4px;background:var(--green);transition:width .4s;}
  .badge.off{background:rgba(127,147,179,.18);color:var(--muted);}
  .card{background:var(--panel);border:1px solid var(--border);border-radius:12px;padding:18px;}
  .stat-card .head{display:flex;justify-content:space-between;align-items:center;margin-bottom:10px;}
  .stat-card .name{font-size:13px;color:var(--muted);}
  .badge{font-size:11px;padding:3px 9px;border-radius:20px;font-weight:600;}
  .badge.ok{background:rgba(46,204,113,.15);color:var(--green);}
  .badge.warn{background:rgba(244,180,0,.15);color:var(--yellow);}
  .badge.alarm{background:rgba(231,76,60,.2);color:var(--red);animation:blink 1s infinite;}
  @keyframes blink{50%{opacity:.4;}}
  .stat-card{background:linear-gradient(145deg,#1b2940,#151f2e);color:var(--text);border:1px solid var(--border);border-radius:16px;box-shadow:0 4px 16px rgba(0,0,0,.35);display:flex;flex-direction:column;}
  .stat-card .head{align-items:flex-start;gap:10px;}
  .stat-card .name{font-size:20px;font-weight:800;color:#fff;white-space:normal;line-height:1.3;}
  .stat-card .body{display:flex;align-items:center;justify-content:space-between;gap:14px;margin-top:14px;flex:1;}
  .stat-card .value{font-size:64px;font-weight:800;font-family:"Segoe UI","Helvetica Neue",Arial,sans-serif;color:#27ae60;line-height:1;}
  .stat-card .value small{font-size:26px;color:#27ae60;font-weight:700;margin-left:6px;}
  .stat-card .meta{color:#6b7688;}
  .stat-card .value small{font-size:15px;color:var(--muted);font-weight:400;margin-left:4px;}
  .stat-card .meta{font-size:12px;color:var(--muted);margin-top:8px;display:flex;justify-content:space-between;}
  .stat-card .dir{margin-top:6px;font-size:13px;color:var(--text);}
  .panel{background:var(--panel);border:1px solid var(--border);border-radius:12px;padding:20px;margin-bottom:20px;}
  .panel h3{font-size:15px;margin-bottom:16px;display:flex;align-items:center;justify-content:space-between;gap:10px;}
  .panel h3 .right{font-size:12px;color:var(--muted);font-weight:400;}
  .grid-2{display:grid;grid-template-columns:2fr 1fr;gap:20px;}
  @media(max-width:1100px){.grid-2{grid-template-columns:1fr;}}
  .chart{width:100%;height:320px;}
  .chart-sm{height:340px;}
  /* Tables */
  table{width:100%;border-collapse:collapse;font-size:13px;}
  th,td{padding:10px 12px;text-align:left;border-bottom:1px solid var(--border);white-space:nowrap;}
  th{color:var(--muted);font-weight:500;background:var(--panel2);font-size:12px;letter-spacing:.5px;}
  tr:hover td{background:rgba(47,157,244,.05);}
  .tag{display:inline-block;padding:2px 8px;border-radius:4px;font-size:11px;}
  .tag.on{background:rgba(46,204,113,.15);color:var(--green);}
  .tag.off{background:rgba(127,147,179,.15);color:var(--muted);}
  .tag.alarm{background:rgba(231,76,60,.2);color:var(--red);}
  /* Filter bar */
  .filter-bar{display:flex;gap:12px;flex-wrap:wrap;align-items:flex-end;margin-bottom:16px;}
  .filter-bar .form-group{margin-bottom:0;min-width:160px;}
  /* Modal */
  .modal-mask{position:fixed;inset:0;background:rgba(0,0,0,.55);display:none;align-items:center;justify-content:center;z-index:90;}
  .modal-mask.show{display:flex;}
  .modal{background:var(--panel);border:1px solid var(--border);border-radius:12px;width:460px;max-width:92vw;padding:24px;}
  .modal h3{margin-bottom:20px;}
  .modal .actions{display:flex;justify-content:flex-end;gap:10px;margin-top:22px;}
  /* Toast & alarm banner */
  #toast{position:fixed;top:70px;right:24px;z-index:200;display:flex;flex-direction:column;gap:10px;}
  .toast-item{background:var(--panel);border:1px solid var(--border);border-left:4px solid var(--accent);border-radius:8px;padding:12px 16px;font-size:13px;box-shadow:0 8px 24px rgba(0,0,0,.4);min-width:300px;max-width:420px;animation:slideIn .3s;}
  .toast-item.alarm{border-left-color:var(--red);}
  @keyframes slideIn{from{transform:translateX(40px);opacity:0;}}
  #alarmBanner{display:none;position:fixed;bottom:0;left:230px;right:0;background:linear-gradient(90deg,#7a1f16,#e74c3c);color:#fff;padding:12px 24px;font-size:14px;font-weight:600;z-index:80;align-items:center;gap:12px;}
  #alarmBanner.show{display:flex;animation:slideIn .3s;}
  /* Settings */
  .threshold-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(270px,1fr));gap:16px;}
  .threshold-card{background:var(--panel2);border:1px solid var(--border);border-radius:10px;padding:18px;}
  .threshold-card h4{font-size:14px;margin-bottom:14px;display:flex;align-items:center;gap:8px;}
  .input-row{display:flex;align-items:center;gap:8px;margin-bottom:12px;}
  .input-row input{width:90px;padding:8px 10px;background:var(--panel);border:1px solid var(--border);border-radius:6px;color:var(--text);outline:none;}
  .input-row span{font-size:13px;color:var(--muted);}
  .slider-row{display:flex;align-items:center;gap:10px;font-size:12px;color:var(--muted);}
  input[type=range]{flex:1;accent-color:var(--accent);}
  .notify-list{display:flex;flex-direction:column;gap:8px;}
  .notify-item{display:flex;align-items:center;gap:10px;background:var(--panel2);border:1px solid var(--border);border-radius:8px;padding:10px 14px;font-size:13px;}
  .notify-item input[type=text]{width:130px;background:var(--panel);border:1px solid var(--border);border-radius:6px;padding:7px 10px;color:var(--text);outline:none;}
  .proto-note{position:fixed;bottom:14px;right:16px;font-size:11px;color:#5a6c88;z-index:60;}