:root {
  --bg:       #0f1117;
  --surface:  #1a1d27;
  --border:   #2d3147;
  --text:     #e2e8f0;
  --muted:    #8892a4;
  --accent:   #4e9af1;
  --ok:       #4ade80;
  --warn:     #f87171;
}

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

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

/* ── Layout ── */
.page { max-width: 1100px; margin: 0 auto; padding: 1.5rem; }

/* ── Header ── */
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 1.5rem;
}
header h1 { font-size: 1.3rem; font-weight: 600; }
.header-right { display: flex; gap: 0.75rem; align-items: center; }
.device-name { font-size: 0.9rem; color: var(--muted); }

/* ── Controls ── */
select, button {
  background: var(--surface);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.4rem 0.75rem;
  font-size: 0.875rem;
  cursor: pointer;
}
select:focus, button:focus { outline: 2px solid var(--accent); outline-offset: 2px; }
.btn-logout { color: var(--muted); }
.btn-logout:hover { color: var(--warn); border-color: var(--warn); }

/* ── Current value cards ── */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(190px, 1fr));
  gap: 1rem;
  margin-bottom: 2rem;
}
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.25rem;
}
.card-label { font-size: 0.78rem; color: var(--muted); margin-bottom: 0.4rem; text-transform: uppercase; letter-spacing: 0.04em; }
.card-value { font-size: 2.1rem; font-weight: 700; line-height: 1; }
.card-unit  { font-size: 1rem; font-weight: 400; color: var(--muted); margin-left: 0.15rem; }
.card-time  { font-size: 0.75rem; color: var(--muted); margin-top: 0.5rem; }
.card-ok   .card-value { color: var(--ok); }
.card-warn .card-value { color: var(--warn); }

/* ── Charts ── */
.charts {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(460px, 1fr));
  gap: 1.25rem;
}
.chart-wrapper {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.25rem;
}
.chart-wrapper h3 { font-size: 0.8rem; color: var(--muted); margin-bottom: 0.9rem; text-transform: uppercase; letter-spacing: 0.04em; }

/* ── Controls bar ── */
.controls {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  padding: 0.75rem 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  margin-bottom: 1.5rem;
}
.control-group { display: flex; align-items: center; gap: 0.4rem; }
.control-group label { font-size: 0.8rem; color: var(--muted); white-space: nowrap; }
.last-updated { font-size: 0.78rem; color: var(--muted); margin-left: auto; }

/* ── Empty state ── */
.empty-state { color: var(--muted); text-align: center; margin-top: 4rem; }

/* ── Login ── */
.login-wrapper {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  padding: 1rem;
}
.login-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 2.5rem;
  width: 100%;
  max-width: 360px;
}
.login-card h1 { font-size: 1.15rem; text-align: center; margin-bottom: 1.75rem; }
.form-group { margin-bottom: 1rem; }
.form-group label { display: block; font-size: 0.82rem; color: var(--muted); margin-bottom: 0.35rem; }
.form-group input {
  width: 100%;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.6rem 0.8rem;
  font-size: 0.95rem;
}
.form-group input:focus { outline: none; border-color: var(--accent); }
.btn-primary {
  width: 100%;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  padding: 0.7rem;
  font-size: 1rem;
  cursor: pointer;
  margin-top: 0.5rem;
}
.btn-primary:hover { opacity: 0.88; }
.error { color: var(--warn); font-size: 0.83rem; margin-top: 0.85rem; text-align: center; }