:root {
  --bg: #f8fafc;
  --surface: #ffffff;
  --text: #0f172a;
  --muted: #64748b;
  --border: #e2e8f0;
  --accent: #2563eb;
  --ok: #16a34a;
  --yellow: #d97706;
  --red: #dc2626;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f172a;
    --surface: #1e293b;
    --text: #f1f5f9;
    --muted: #94a3b8;
    --border: #334155;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 1.5rem;
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.75rem 1.5rem;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}

.topbar .brand { font-weight: 700; color: var(--text); }

.topbar nav { display: flex; align-items: center; gap: 1rem; }

.user-badge { color: var(--muted); font-size: 0.9rem; }

.link-button {
  background: none;
  border: none;
  color: var(--accent);
  cursor: pointer;
  font: inherit;
  padding: 0;
}

.inline-form { display: inline; }

h1 { margin-top: 0; }

.sensor-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1rem;
}

.sensor-card {
  display: block;
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 6px solid var(--muted);
  border-radius: 8px;
  padding: 1rem;
  color: var(--text);
}
.sensor-card:hover { text-decoration: none; box-shadow: 0 2px 8px rgba(0,0,0,0.08); }
.sensor-card.zone-ok { border-left-color: var(--ok); }
.sensor-card.zone-yellow { border-left-color: var(--yellow); }
.sensor-card.zone-red { border-left-color: var(--red); }
.sensor-card.inactive { opacity: 0.55; }

.sensor-card-header { display: flex; justify-content: space-between; align-items: center; }
.sensor-name { font-weight: 600; }

.zone-badge {
  font-size: 0.7rem;
  text-transform: uppercase;
  padding: 0.15rem 0.5rem;
  border-radius: 999px;
  color: #fff;
}
.zone-badge.zone-ok { background: var(--ok); }
.zone-badge.zone-yellow { background: var(--yellow); }
.zone-badge.zone-red { background: var(--red); }

.sensor-value { font-size: 2rem; font-weight: 700; margin: 0.5rem 0; }
.sensor-meta { font-size: 0.8rem; color: var(--muted); }
.inactive-badge {
  background: var(--muted);
  color: #fff;
  border-radius: 4px;
  padding: 0.05rem 0.4rem;
  font-size: 0.7rem;
  margin-left: 0.4rem;
}

.empty { color: var(--muted); }

.login-box {
  max-width: 360px;
  margin: 3rem auto;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.5rem;
}
.login-box form { display: flex; flex-direction: column; gap: 0.75rem; }
.login-box label { display: flex; flex-direction: column; gap: 0.25rem; font-size: 0.9rem; }
input[type="text"], input[type="password"], input[type="number"] {
  padding: 0.4rem 0.5rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--bg);
  color: var(--text);
  font: inherit;
}
button {
  padding: 0.5rem 0.9rem;
  border: none;
  border-radius: 4px;
  background: var(--accent);
  color: #fff;
  cursor: pointer;
  font: inherit;
}
button:hover { opacity: 0.9; }

.error { color: var(--red); }
.success { color: var(--ok); }

.range-tabs { display: flex; gap: 0.75rem; align-items: center; margin: 1rem 0; }
.range-tabs a { padding: 0.3rem 0.7rem; border: 1px solid var(--border); border-radius: 4px; }
.range-tabs a.active { background: var(--accent); color: #fff; }
.range-tabs .csv-link { margin-left: auto; }

.custom-range {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: center;
  margin-bottom: 1.5rem;
  font-size: 0.9rem;
  color: var(--muted);
}
.custom-range label { display: flex; align-items: center; gap: 0.35rem; color: var(--text); }
.custom-range input[type="datetime-local"] {
  padding: 0.3rem 0.4rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--bg);
  color: var(--text);
  font: inherit;
}
.muted-note { margin-left: auto; font-size: 0.8rem; }

.stats-row { display: flex; gap: 1.5rem; margin-bottom: 1rem; }
.stat { background: var(--surface); border: 1px solid var(--border); border-radius: 8px; padding: 0.6rem 1rem; }
.stat-label { display: block; font-size: 0.75rem; color: var(--muted); }
.stat-value { display: block; font-size: 1.3rem; font-weight: 700; }

.table-wrap { overflow-x: auto; }
.admin-table { width: 100%; border-collapse: collapse; margin-bottom: 1rem; }
.admin-table th, .admin-table td {
  border: 1px solid var(--border);
  padding: 0.4rem 0.5rem;
  text-align: left;
  font-size: 0.9rem;
}
.admin-table th { background: var(--surface); }
.admin-table input[type="text"], .admin-table input[type="number"] { width: 100%; }
.save-status.ok { color: var(--ok); }
.save-status.error { color: var(--red); }