:root {
  --bg: #f0f4f8;
  --bg2: #ffffff;
  --card: #ffffff;
  --card-hover: #f7f9fc;
  --border: #e2e8f0;
  --text: #1e293b;
  --muted: #64748b;
  --accent: #3b82f6;
  --accent-light: #2563eb;
  --green: #16a34a;
  --green-dim: rgba(22,163,74,.1);
  --blue: #3b82f6;
  --blue-dim: rgba(59,130,246,.08);
  --orange: #d97706;
  --orange-dim: rgba(217,119,6,.08);
  --red: #dc2626;
  --red-dim: rgba(220,38,38,.08);
  --radius: 10px;
  --shadow: 0 1px 3px rgba(0,0,0,.06), 0 1px 2px rgba(0,0,0,.04);
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

/* ─── Login ──────────────────────────────────────────────────────────────── */
.login-page {
  display: flex; align-items: center; justify-content: center;
  min-height: 100vh; background: linear-gradient(135deg, #1e3a5f 0%, #0f172a 100%);
}
.login-box {
  background: #fff; border-radius: 16px;
  padding: 40px; width: 380px; max-width: 90vw; box-shadow: 0 20px 60px rgba(0,0,0,.3);
}
.login-box .logo { text-align: center; margin-bottom: 24px; }
.login-box .logo h1 { font-size: 22px; font-weight: 700; color: #1e293b; }
.login-box .logo p { font-size: 13px; color: #64748b; margin-top: 4px; }
.login-box label { display: block; font-size: 12px; color: #64748b; margin-bottom: 4px; font-weight: 500; text-transform: uppercase; letter-spacing: .5px; }
.login-box input { width: 100%; background: #f8fafc; border: 1px solid #e2e8f0; color: #1e293b; padding: 10px 14px; border-radius: var(--radius); font-size: 14px; margin-bottom: 16px; outline: none; transition: border .2s; }
.login-box input:focus { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(59,130,246,.1); }
.login-box button { width: 100%; background: var(--accent); color: #fff; border: none; padding: 11px; border-radius: var(--radius); font-size: 14px; font-weight: 600; cursor: pointer; transition: all .2s; }
.login-box button:hover { background: var(--accent-light); }
.login-box .error { background: #fef2f2; color: #dc2626; padding: 8px 12px; border-radius: var(--radius); font-size: 13px; margin-bottom: 12px; display: none; border: 1px solid #fecaca; }

/* ─── App Layout ─────────────────────────────────────────────────────────── */
.app { display: flex; flex-direction: column; height: 100vh; overflow: hidden; }

.topbar {
  background: var(--bg2); border-bottom: 1px solid var(--border);
  padding: 0 20px; height: 52px; display: flex; align-items: center; gap: 12px; flex-shrink: 0;
}
.topbar .logo { display: flex; align-items: center; gap: 8px; }
.topbar .logo svg { width: 24px; height: 24px; color: var(--accent); }
.topbar .logo span { font-size: 15px; font-weight: 700; color: var(--text); letter-spacing: -.3px; }
.topbar .nav { display: flex; gap: 2px; margin-left: 24px; }
.topbar .nav button {
  background: none; border: none; color: var(--muted); padding: 6px 14px;
  border-radius: 6px; font-size: 13px; cursor: pointer; transition: all .15s;
}
.topbar .nav button:hover { color: var(--text); background: rgba(0,0,0,.04); }
.topbar .nav button.active { color: var(--accent); background: var(--blue-dim); font-weight: 600; }
.topbar .spacer { flex: 1; }
.topbar .user-info { font-size: 12px; color: var(--muted); display: flex; align-items: center; gap: 8px; }
.topbar .user-info .name { color: var(--text); font-weight: 500; }
.topbar .btn-sm {
  background: none; border: 1px solid var(--border); color: var(--muted);
  padding: 4px 12px; border-radius: 6px; font-size: 12px; cursor: pointer;
}
.topbar .btn-sm:hover { border-color: var(--accent); color: var(--accent); }
.topbar .logo svg { color: var(--accent); }

.layout { display: flex; flex: 1; overflow: hidden; }

/* ─── Sidebar ────────────────────────────────────────────────────────────── */
.sidebar {
  width: 260px; min-width: 260px; background: var(--bg2);
  border-right: 1px solid var(--border); display: flex; flex-direction: column; overflow: hidden;
}
.sidebar-search { padding: 12px; border-bottom: 1px solid var(--border); }
.sidebar-search input {
  width: 100%; background: var(--bg); border: 1px solid var(--border); color: var(--text);
  padding: 7px 10px 7px 32px; border-radius: 6px; font-size: 12px; outline: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='14' height='14' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2'%3E%3Ccircle cx='11' cy='11' r='8'/%3E%3Cline x1='21' y1='21' x2='16.65' y2='16.65'/%3E%3C/svg%3E");
  background-repeat: no-repeat; background-position: 10px center;
}
.sidebar-counts { padding: 6px 12px; font-size: 10px; color: var(--muted); display: flex; gap: 8px; border-bottom: 1px solid var(--border); }
.sidebar-counts .dot { display: inline-block; width: 7px; height: 7px; border-radius: 50%; margin-right: 3px; vertical-align: middle; }

.device-list { flex: 1; overflow-y: auto; padding: 4px 8px; }
.group-label {
  font-size: 10px; font-weight: 700; text-transform: uppercase; letter-spacing: .8px;
  color: var(--muted); padding: 10px 8px 4px; display: flex; align-items: center; gap: 6px;
}
.group-label .count { margin-left: auto; font-weight: 400; }

.dev-item {
  padding: 7px 10px; border-radius: 6px; cursor: pointer; font-size: 12px;
  margin-bottom: 1px; display: flex; align-items: center; gap: 8px; transition: background .1s;
}
.dev-item:hover { background: var(--card-hover); }
.dev-item.active { background: var(--blue-dim); border-left: 3px solid var(--accent); }
.dev-item .dot { width: 7px; height: 7px; border-radius: 50%; flex-shrink: 0; }
.dev-item .dot.online { background: var(--green); }
.dev-item .dot.alive { background: var(--blue); }
.dev-item .dot.stale { background: var(--orange); }
.dev-item .dot.offline { background: #cbd5e1; }
.dev-item .info { flex: 1; overflow: hidden; }
.dev-item .info .name { font-weight: 500; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.dev-item .info .sub { font-size: 10px; color: var(--muted); }
.dev-item .warn { color: var(--orange); font-size: 12px; }

/* ─── Main Content ───────────────────────────────────────────────────────── */
.main { flex: 1; overflow-y: auto; padding: 20px; }

.page-title { font-size: 18px; font-weight: 700; margin-bottom: 4px; }
.page-subtitle { font-size: 12px; color: var(--muted); margin-bottom: 16px; }

/* Time controls */
.time-bar { display: flex; gap: 4px; margin-bottom: 16px; }
.time-bar button {
  background: var(--card); border: 1px solid var(--border); color: var(--text);
  padding: 5px 12px; border-radius: 6px; font-size: 12px; cursor: pointer; transition: all .15s;
}
.time-bar button:hover { border-color: var(--accent); }
.time-bar button.active { background: var(--blue-dim); border-color: var(--accent); color: var(--accent-light); }

/* Value cards */
.values-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); gap: 10px; margin-bottom: 20px; }
.val-card {
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 14px; text-align: center; position: relative; overflow: hidden;
}
.val-card::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0; height: 2px;
  background: var(--field-color, var(--accent));
}
.val-card .label { font-size: 10px; color: var(--muted); text-transform: uppercase; letter-spacing: .5px; margin-bottom: 6px; }
.val-card .number { font-size: 26px; font-weight: 700; color: var(--field-color, var(--text)); line-height: 1; }
.val-card .unit { font-size: 12px; color: var(--muted); margin-left: 2px; }
.val-card .ago { font-size: 10px; color: var(--muted); margin-top: 6px; }

/* Charts */
.charts-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
@media (max-width: 1000px) { .charts-grid { grid-template-columns: 1fr; } }
.chart-box {
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 14px;
}
.chart-box h3 { font-size: 13px; color: var(--muted); margin-bottom: 8px; font-weight: 500; }
.chart-box canvas { width: 100% !important; height: 220px !important; }

/* Overview grid */
.overview-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 10px; }
.overview-card {
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 14px; cursor: pointer; transition: all .15s;
}
.overview-card:hover { border-color: var(--accent); transform: translateY(-1px); }
.overview-card .header { display: flex; align-items: center; gap: 8px; margin-bottom: 10px; }
.overview-card .header .dot { width: 8px; height: 8px; border-radius: 50%; }
.overview-card .header .name { font-size: 13px; font-weight: 600; flex: 1; }
.overview-card .header .ago { font-size: 10px; color: var(--muted); }
.overview-card .metrics { display: grid; grid-template-columns: 1fr 1fr; gap: 4px; }
.overview-card .metric { font-size: 11px; }
.overview-card .metric .lbl { color: var(--muted); }
.overview-card .metric .val { font-weight: 600; }

/* Warning banner */
.warning-banner {
  background: var(--orange-dim); border: 1px solid rgba(245,158,11,.25); border-radius: var(--radius);
  padding: 10px 14px; margin-bottom: 14px; font-size: 12px; line-height: 1.5;
}
.warning-banner strong { color: var(--orange); }

/* Empty state */
.empty-state { display: flex; align-items: center; justify-content: center; height: 100%; color: var(--muted); font-size: 14px; }

/* Settings page */
.settings-form { max-width: 600px; }
.settings-form .field { margin-bottom: 16px; }
.settings-form label { display: block; font-size: 12px; color: var(--muted); margin-bottom: 4px; font-weight: 500; }
.settings-form input, .settings-form select { width: 100%; background: #fff; border: 1px solid #cbd5e1; color: var(--text); padding: 8px 12px; border-radius: 6px; font-size: 13px; }
.settings-form input:focus, .settings-form select:focus { border-color: var(--accent); outline: none; box-shadow: 0 0 0 3px rgba(59,130,246,.1); }
.settings-form button { background: var(--accent); color: #fff; border: none; padding: 8px 20px; border-radius: 6px; font-size: 13px; font-weight: 600; cursor: pointer; }

/* Modal */
.modal-overlay { display: none; position: fixed; inset: 0; background: rgba(0,0,0,.6); z-index: 100; align-items: center; justify-content: center; }
.modal-overlay.show { display: flex; }
.modal-box { background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 24px; width: 420px; max-width: 90vw; }
.modal-box h2 { font-size: 16px; margin-bottom: 16px; }
.modal-box label { display: block; font-size: 12px; color: var(--muted); margin-bottom: 4px; }
.modal-box input, .modal-box select { width: 100%; background: var(--bg); border: 1px solid var(--border); color: var(--text); padding: 8px 12px; border-radius: 6px; font-size: 13px; margin-bottom: 12px; }
.modal-box .btns { display: flex; gap: 8px; justify-content: flex-end; }
.modal-box .btns button { padding: 8px 18px; border-radius: 6px; border: none; cursor: pointer; font-size: 13px; font-weight: 600; }
.modal-box .btn-cancel { background: var(--border); color: var(--text); }
.modal-box .btn-primary { background: var(--accent); color: #fff; }

/* Scrollbar */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: #cbd5e1; border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: #94a3b8; }