:root {
  --color-bg: #f5f7fa;
  --color-primary: #1c6dd0;
  --color-secondary: #5e81ac;
  --color-text: #1a1a1a;
  --color-muted: #666;
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 2rem;
  --radius-sm: 4px;
  --radius-md: 8px;
  --font-base: 'Segoe UI', sans-serif;
  --max-width-content: 1200px;
}

/* ======================== */
/* Header and Toolbar       */
/* ======================== */

.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: var(--color-bg);
  border-bottom: 1px solid #ddd;
  padding: var(--spacing-md);
  font-family: var(--font-base);
}

.app-header h1 {
  font-size: 1.25rem;
  color: var(--color-primary);
  margin: 0;
}

.filter-controls {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.filter-controls label {
  font-size: 0.9rem;
  color: var(--color-text);
}

.filter-controls select,
.filter-controls input[type="date"] {
  border: 1px solid #ccc;
  border-radius: var(--radius-sm);
  padding: var(--spacing-xs) var(--spacing-sm);
  background-color: #fff;
  font-family: var(--font-base);
}

/* ======================== */
/* Dashboard and Charts     */
/* ======================== */

.app-main {
  max-width: var(--max-width-content);
  margin: 0 auto;
  padding: var(--spacing-md);
}

.dashboard {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-lg);
}

.chart-panel {
  background-color: #fff;
  border: 1px solid #e0e0e0;
  border-radius: var(--radius-md);
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
  padding: var(--spacing-md);
}

.chart-panel h2 {
  font-size: 1rem;
  color: var(--color-secondary);
  margin-bottom: var(--spacing-sm);
}

.temperature-chart,
.humidity-chart,
.light-chart {
  width: 100%;
  height: 240px;
}

.chart-panel canvas {
  width: 100% !important;
  height: 100% !important;
}

/* ======================== */
/* Footer                   */
/* ======================== */

.app-footer {
  text-align: center;
  font-size: 0.85rem;
  color: var(--color-muted);
  padding: var(--spacing-md);
  border-top: 1px solid #ddd;
  background-color: var(--color-bg);
}

.app-footer small {
  display: block;
  margin-top: var(--spacing-xs);
}

/* ======================== */
/* Responsive Adjustments   */
/* ======================== */

@media (min-width: 640px) {
  .dashboard {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .dashboard {
    grid-template-columns: repeat(3, 1fr);
  }
}