:root {
  --bg: #0f1117;
  --surface: #1a1d2e;
  --border: #2d3147;
  --text: #e2e8f0;
  --text-dim: #718096;
  --solar: #f6c90e;
  --battery: #48bb78;
  --grid: #63b3ed;
  --load: #d53f8c;
  --danger: #fc8181;
  --success: #68d391;
  --warning: #f6ad55;
}

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

body {
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  font-size: 14px;
  min-height: 100vh;
}

/* ── Login ─────────────────────────────────────────────── */
.login-page {
  display: flex;
  align-items: center;
  justify-content: center;
}

.login-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 40px;
  width: 100%;
  max-width: 380px;
}

.login-card h1 { font-size: 22px; margin-bottom: 6px; }
.login-card .subtitle { color: var(--text-dim); margin-bottom: 28px; }

.form-group { margin-bottom: 16px; }
.form-group label { display: block; margin-bottom: 6px; color: var(--text-dim); font-size: 13px; }
.form-group input {
  width: 100%;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text);
  padding: 10px 12px;
  font-size: 14px;
}
.form-group input:focus {
  outline: none;
  border-color: var(--grid);
}

.error-msg {
  color: var(--danger);
  font-size: 13px;
  margin-bottom: 12px;
  padding: 8px 12px;
  background: rgba(252, 129, 129, 0.1);
  border-radius: 6px;
}

/* ── Buttons ───────────────────────────────────────────── */
.btn {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text);
  cursor: pointer;
  font-size: 14px;
  padding: 8px 16px;
  transition: background 0.15s;
}
.btn:hover { background: var(--border); }
.btn-primary { background: #3b5bdb; border-color: #3b5bdb; color: #fff; }
.btn-primary:hover { background: #4c6ef5; }
.btn-danger { background: #c53030; border-color: #c53030; color: #fff; }
.btn-danger:hover { background: #e53e3e; }
.btn-sm { font-size: 12px; padding: 5px 10px; }
.btn-full { width: 100%; padding: 12px; }

/* ── Dashboard header ──────────────────────────────────── */
header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 20px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
}

header h1 { font-size: 18px; font-weight: 600; }
.header-right { display: flex; align-items: center; gap: 12px; }

.status-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  display: inline-block;
  flex-shrink: 0;
}
.status-dot.online { background: var(--battery); box-shadow: 0 0 6px var(--battery); }
.status-dot.offline { background: var(--text-dim); }

#device-select {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text);
  padding: 4px 8px;
  font-size: 13px;
}

.last-updated { color: var(--text-dim); font-size: 12px; }

/* ── Main layout ───────────────────────────────────────── */
main { padding: 20px; max-width: 1200px; margin: 0 auto; }

.empty-state {
  text-align: center;
  padding: 60px 20px;
  color: var(--text-dim);
}

/* ── Panels ────────────────────────────────────────────── */
.panels-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-bottom: 16px;
}

@media (max-width: 900px) { .panels-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 500px) { .panels-grid { grid-template-columns: 1fr; } }

.panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 16px;
}

.panel-title {
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 12px;
}

.panel-solar .panel-title { color: var(--solar); }
.panel-battery .panel-title { color: var(--battery); }
.panel-grid .panel-title { color: var(--grid); }
.panel-load .panel-title { color: var(--load); }

.panel-solar { border-top: 3px solid var(--solar); }
.panel-battery { border-top: 3px solid var(--battery); }
.panel-grid { border-top: 3px solid var(--grid); }
.panel-load { border-top: 3px solid var(--load); }

.metric { display: flex; align-items: baseline; gap: 8px; margin-bottom: 8px; }
.metric:last-child { margin-bottom: 0; }
.metric-label { color: var(--text-dim); font-size: 12px; min-width: 70px; }
.metric-value { font-size: 15px; font-weight: 600; }
.metric-direction { font-size: 12px; color: var(--text-dim); }
.metric-direction.charging, .metric-direction.exporting { color: var(--battery); }
.metric-direction.discharging, .metric-direction.importing { color: var(--danger); }

/* SoC bar */
.soc-bar-container {
  height: 6px;
  background: var(--bg);
  border-radius: 3px;
  margin: 6px 0 10px;
  overflow: hidden;
}
.soc-bar {
  height: 100%;
  border-radius: 3px;
  background: var(--battery);
  transition: width 0.5s ease;
}
.soc-bar.low { background: var(--danger); }
.soc-bar.mid { background: var(--warning); }

/* ── Settings panel ────────────────────────────────────── */
.settings-panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 16px;
  margin-bottom: 16px;
}

.settings-title {
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-dim);
  margin-bottom: 12px;
}

.settings-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 12px;
}

.setting { display: flex; flex-direction: column; gap: 4px; }
.setting-label { font-size: 11px; color: var(--text-dim); text-transform: uppercase; letter-spacing: 0.05em; }
.setting-value { font-size: 14px; font-weight: 500; }

/* ── Controls ──────────────────────────────────────────── */
.controls-panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  overflow: hidden;
}

.controls-panel > summary {
  padding: 14px 16px;
  cursor: pointer;
  font-weight: 600;
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-dim);
  user-select: none;
}

.controls-panel > summary:hover { color: var(--text); }
.controls-panel[open] > summary { border-bottom: 1px solid var(--border); }

.controls-grid {
  padding: 16px;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 20px;
}

.control-group h3 { font-size: 13px; color: var(--text-dim); margin-bottom: 8px; }
.control-form { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.control-form input[type="time"],
.control-form input[type="number"] {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 5px;
  color: var(--text);
  padding: 5px 8px;
  font-size: 13px;
}
.control-form input:focus { outline: none; border-color: var(--grid); }

.control-group-danger { border-top: 1px solid var(--border); padding-top: 16px; }
.hint { font-size: 11px; color: var(--text-dim); margin-top: 6px; }

.command-status {
  margin: 0 16px 16px;
  padding: 10px 14px;
  border-radius: 6px;
  font-size: 13px;
}
.command-status.success { background: rgba(104, 211, 145, 0.15); color: var(--success); }
.command-status.error { background: rgba(252, 129, 129, 0.15); color: var(--danger); }

/* ── History charts ─────────────────────────────────────── */
.charts-section {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 16px;
  margin-top: 16px;
}

.charts-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}

.charts-title {
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-dim);
}

.range-btns { display: flex; gap: 6px; }

.range-btn { color: var(--text-dim); }
.range-btn.active { background: #3b5bdb; border-color: #3b5bdb; color: #fff; }

.charts-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

@media (max-width: 800px) { .charts-grid { grid-template-columns: 1fr; } }

.chart-container {
  position: relative;
  height: 220px;
}