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

:root {
  --color-bg: #f0f2f5;
  --color-text: #333;
  --color-text-muted: #888;
  --color-card-bg: #ffffff;
  --color-header-bg: #2563eb;
  --color-header-text: #ffffff;
  --color-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
  --color-border: #f0f0f0;
  --color-summary-border: #eee;
  --color-active: #2563eb;
  --color-bar-bg: #e5e7eb;
  --color-th-bg: #f9fafb;
  --color-th-text: #6b7280;
  --color-btn-bg: #fff;
  --color-btn-text: #2563eb;
  --color-btn-hover: #e0e7ff;
}

[data-theme="dark"] {
  --color-bg: #111827;
  --color-text: #e5e7eb;
  --color-text-muted: #9ca3af;
  --color-card-bg: #1f2937;
  --color-header-bg: #1e3a5f;
  --color-header-text: #ffffff;
  --color-shadow: 0 1px 3px rgba(0, 0, 0, 0.4);
  --color-border: #374151;
  --color-summary-border: #374151;
  --color-active: #3b82f6;
  --color-bar-bg: #374151;
  --color-th-bg: #1f2937;
  --color-th-text: #d1d5db;
  --color-btn-bg: #374151;
  --color-btn-text: #60a5fa;
  --color-btn-hover: #374151;
}

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

header {
  background: var(--color-header-bg);
  color: var(--color-header-text);
  padding: 1rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.header-info {
  display: flex;
  align-items: center;
  gap: 1rem;
}

button {
  background: var(--color-btn-bg);
  color: var(--color-btn-text);
  border: none;
  padding: 0.5rem 1rem;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 600;
}

button:hover {
  background: var(--color-btn-hover);
}

#dashboard {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 1.5rem;
  padding: 1.5rem;
  max-width: 1400px;
  margin: 0 auto;
}

aside#sidebar {
  position: sticky;
  top: 1.5rem;
  align-self: start;
}

.card {
  background: var(--color-card-bg);
  border-radius: 10px;
  padding: 1.25rem;
  box-shadow: var(--color-shadow);
  margin-bottom: 1.5rem;
}

.chart-card {
  margin: 0;
}

.chart-container {
  position: relative;
  height: 320px;
}

/* Sidebar sensor list */
#sensorList {
  list-style: none;
  padding: 0;
}

#sensorList li {
  padding: 0.6rem 0.75rem;
  margin-bottom: 0.4rem;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.95rem;
  transition: background 0.2s;
}

#sensorList li:hover {
  background: var(--color-btn-hover);
}

#sensorList li.active {
  background: var(--color-active);
  color: #fff;
  font-weight: 600;
}

/* Summary card */
.summary {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.75rem;
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--color-summary-border);
}

.summary-stat {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
}

.summary-stat .label {
  color: var(--color-text-muted);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.summary-stat div {
  font-weight: 700;
  font-size: 1.1rem;
}

/* Cards grid */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1.25rem;
  margin: 1.5rem 0;
}

.sensor-card {
  background: var(--color-card-bg);
  border-radius: 10px;
  padding: 1.25rem;
  box-shadow: var(--color-shadow);
  text-align: center;
}

.sensor-card h3 {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  margin-bottom: 0.5rem;
}

.sensor-card .value {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
}

.sensor-card .meta {
  font-size: 0.8rem;
  color: var(--color-text-muted);
  margin-bottom: 1rem;
}

/* Range bar */
.range-labels {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.75rem;
  color: var(--color-text-muted);
}

.range-bar {
  flex: 1;
  height: 8px;
  background: var(--color-bar-bg);
  border-radius: 4px;
  overflow: hidden;
}

.range-bar-fill {
  height: 100%;
  border-radius: 4px;
  transition: width 0.3s ease;
}

/* Table */
.table-container {
  overflow-x: auto;
  margin-top: 1rem;
}

#readingsTable {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

#readingsTable th {
  background: var(--color-th-bg);
  color: var(--color-th-text);
  font-weight: 600;
  text-align: left;
  padding: 0.75rem 1rem;
  white-space: nowrap;
}

#readingsTable td {
  padding: 0.65rem 1rem;
  border-bottom: 1px solid var(--color-border);
}

#readingsTable tbody tr:hover {
  background: var(--color-btn-hover);
}

/* Legend */
#legend {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 1rem;
  justify-content: center;
  font-size: 0.85rem;
}

/* Responsive */
@media (max-width: 768px) {
  header {
    flex-direction: column;
    gap: 0.75rem;
    text-align: center;
  }

  #dashboard {
    grid-template-columns: 1fr;
    padding: 1rem;
  }

  aside#sidebar {
    position: static;
  }

  .cards-grid {
    grid-template-columns: 1fr;
  }
}