:root {
  --bg: #f0f2f5;
  --card-bg: #ffffff;
  --text: #1a1a2e;
  --text-secondary: #6b7280;
  --accent: #4a90d9;
  --accent-light: #e8f0fe;
  --border: #e5e7eb;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.08), 0 1px 2px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 4px 12px rgba(0, 0, 0, 0.1);
  --radius: 12px;
}

[data-theme="dark"] {
  --bg: #0f1117;
  --card-bg: #1a1d27;
  --text: #e8eaf0;
  --text-secondary: #9ba3af;
  --accent: #5ba3e8;
  --accent-light: #1a2a3e;
  --border: #2d3141;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.4), 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 4px 12px rgba(0, 0, 0, 0.5);
}

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

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 24px 16px;
}

/* Header */
header {
  text-align: center;
  margin-bottom: 32px;
  position: relative;
}

header h1 {
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 4px;
}

.theme-toggle {
  position: absolute;
  top: 0;
  right: 0;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 6px 10px;
  font-size: 1.1rem;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
  line-height: 1;
}

.theme-toggle:hover {
  border-color: var(--accent);
}

.subtitle {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.last-updated {
  color: var(--text-secondary);
  font-size: 0.8rem;
  margin-top: 8px;
}

/* Cards */
.cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-bottom: 24px;
}

.card {
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.card-header {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 16px 20px;
  border-bottom: 1px solid var(--border);
}

.card-header h2 {
  font-size: 1rem;
  font-weight: 600;
  flex: 1;
}

.card-icon {
  font-size: 1.3rem;
}

.source-badge {
  font-size: 0.7rem;
  font-weight: 500;
  color: var(--accent);
  background: var(--accent-light);
  padding: 2px 8px;
  border-radius: 10px;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.sensor-time {
  font-size: 0.7rem;
  color: var(--text-secondary);
}

.card-body {
  padding: 20px;
}

/* Metrics */
.primary-metric {
  text-align: center;
  margin-bottom: 20px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
}

.primary-metric .metric-value {
  font-size: 3rem;
  font-weight: 700;
  color: var(--text);
  line-height: 1;
}

.primary-metric .metric-unit {
  font-size: 1.2rem;
  color: var(--text-secondary);
  vertical-align: super;
}

.primary-metric .metric-label {
  display: block;
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-top: 4px;
}

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

.metric {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
}

.metric-icon {
  font-size: 1.2rem;
  margin-bottom: 2px;
}

.metric-value {
  font-size: 1.4rem;
  font-weight: 600;
}

.metric-unit {
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.metric-label {
  font-size: 0.75rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

/* AQI Badge */
.aqi-badge {
  display: inline-block;
  padding: 4px 14px;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
  color: #fff;
  background: #9ca3af;
  margin-top: 8px;
}

/* Charts */
.charts {
  display: grid;
  gap: 20px;
}

.chart-card .card-header {
  flex-wrap: wrap;
}

.chart-controls {
  display: flex;
  gap: 4px;
}

.time-btn {
  background: none;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 4px 10px;
  font-size: 0.75rem;
  font-family: inherit;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.15s;
}

.time-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.time-btn.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.chart-updated {
  font-size: 0.7rem;
  color: var(--text-secondary);
  margin-left: auto;
}

.chart-container {
  padding: 16px 20px 20px;
  height: 250px;
}

/* Forecast Section */
.forecast {
  display: grid;
  gap: 20px;
  margin-bottom: 24px;
}

.forecast-card-body {
  padding: 16px 20px;
}

.daily-grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 8px;
}

.daily-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  padding: 10px 4px;
  border-radius: 8px;
  background: var(--bg);
  text-align: center;
}

.daily-label {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.daily-emoji {
  font-size: 1.6rem;
  line-height: 1;
}

.daily-temps {
  display: flex;
  gap: 4px;
  align-items: baseline;
}

.daily-high {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text);
}

.daily-low {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.daily-pop {
  font-size: 0.72rem;
  color: var(--text-secondary);
}

.hourly-strip {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding-bottom: 4px;
  scrollbar-width: thin;
  scrollbar-color: var(--border) transparent;
}

.hourly-strip::-webkit-scrollbar {
  height: 4px;
}

.hourly-strip::-webkit-scrollbar-track {
  background: transparent;
}

.hourly-strip::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 2px;
}

.hourly-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  padding: 10px;
  border-radius: 8px;
  background: var(--bg);
  min-width: 72px;
  flex-shrink: 0;
  text-align: center;
}

.hourly-time {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.hourly-emoji {
  font-size: 1.4rem;
  line-height: 1;
}

.hourly-temp {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text);
}

.hourly-pop,
.hourly-wind {
  font-size: 0.7rem;
  color: var(--text-secondary);
}

/* Version */
.version {
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.7rem;
  margin-top: 24px;
  opacity: 0.5;
}

/* Responsive */
@media (max-width: 720px) {
  .daily-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

@media (max-width: 640px) {
  .cards {
    grid-template-columns: 1fr;
  }

  .primary-metric .metric-value {
    font-size: 2.5rem;
  }

  .container {
    padding: 16px 12px;
  }

  header h1 {
    font-size: 1.6rem;
  }
}