:root {
  --primary-color: #1a73e8;
  --text-color: #202124;
  --background-color: #f8f9fa;
  --card-background: #ffffff;
  --border-radius: 12px;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.12);
  --sidebar-width: min(260px, 25vw);
  --success-color: #34a853;
  --warning-color: #fbbc04;
  --danger-color: #ea4335;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

* {
  box-sizing: border-box;
}

.wrapper {
  display: flex;
  min-height: 100vh;
  background: var(--background-color);
}

.sidebar {
  width: var(--sidebar-width);
  background: var(--card-background);
  padding: 16px;
  position: fixed;
  height: 100vh;
  overflow-y: auto;
  border-right: 1px solid rgba(0, 0, 0, 0.08);
}

.sidebar-header {
  padding-bottom: 16px;
  border-bottom: 1px solid #e8eaed;
  margin-bottom: 16px;
}

.sidebar-header h1 {
  font-size: 1.2em;
  color: var(--text-color);
  margin: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.search-wrapper,
.select-wrapper {
  position: relative;
  margin-bottom: 12px;
}

.search-input,
.aqi-filter,
.time-filter {
  width: 100%;
  padding: 8px 12px 8px 32px;
  border: 1px solid #e8eaed;
  border-radius: 8px;
  font-size: 0.9em;
}

.time-filter + .time-filter {
  margin-top: 4px;
  margin-bottom: 8px;
}

.search-icon,
.filter-icon,
.time-icon {
  position: absolute;
  left: 10px;
  top: 50%;
  transform: translateY(-50%);
  color: #5f6368;
  font-size: 0.9em;
}

.stats-overview {
  display: grid;
  gap: 12px;
}

.stat-item {
  background: var(--background-color);
  padding: 12px;
  border-radius: 8px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.stat-icon {
  font-size: 0.9em;
  color: var(--primary-color);
}

.stat-label {
  font-size: 0.8em;
  color: #5f6368;
}

.stat-value {
  font-size: 1.1em;
  font-weight: 500;
  color: var(--text-color);
}

.main-content {
  flex: 1;
  margin-left: var(--sidebar-width);
  padding: 8px;
}

.chart-container,
.cities-container {
  background: var(--card-background);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow);
  margin-bottom: 16px;
}

.chart-header,
.cities-header {
  padding: 12px 16px;
  border-bottom: 1px solid #e8eaed;
}

.chart-header h2,
.cities-header h2 {
  margin: 0;
  font-size: 1em;
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text-color);
  
}

.chart-section {
  padding: 8px;
  height: 400px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
  border-radius: 8px;
}

.cities-grid-container {
  max-height: 500px;
  overflow-y: auto;
  padding-right: 10px;
  margin-top: 16px;
}



.cities-grid-container::-webkit-scrollbar {
  width: 8px;
}

.cities-grid-container::-webkit-scrollbar-track {
  background: #f1f3f4;
  border-radius: 4px;
}

.cities-grid-container::-webkit-scrollbar-thumb {
  background: #dadce0;
  border-radius: 4px;
}

.cities-grid-container::-webkit-scrollbar-thumb:hover {
  background: #bdc1c6;
}

.cities-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 12px;
  padding: 16px;
}

.city-card {
  background: var(--card-background);
  border-radius: 8px;
  padding: 12px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  position: relative;
  transition: all 0.3s ease;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

.city-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.12);
}

.city-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 4px;
}

.header-left {
  display: flex;
  align-items: center;
  gap: 8px;
}

.aqi-value.good {
  background: rgba(52, 168, 83, 0.1);
  color: var(--success-color);
}

.aqi-value.moderate {
  background: rgba(251, 188, 4, 0.1);
  color: var(--warning-color);
}

.aqi-value.unhealthy {
  background: rgba(234, 67, 53, 0.1);
  color: var(--danger-color);
}

.aqi-value.very-unhealthy {
  background: rgba(161, 66, 244, 0.1);
  color: #a142f4;
}

.city-card-content {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 8px;
}

.info-item {
  background: rgba(0, 0, 0, 0.02);
  padding: 6px;
  border-radius: 6px;
}

.info-item strong {
  font-size: 0.7rem;
  color: #5f6368;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  display: block;
  margin-bottom: 2px;
}

.info-item span {
  font-size: 0.8rem;
  color: var(--text-color);
  font-weight: 500;
}

.update-time {
  font-size: 0.65rem;
  color: #80868b;
  text-align: right;
  margin-top: 2px;
}

/* Responsive adjustments */
@media (max-width: 1600px) {
  .cities-grid {
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  }
}

@media (max-width: 480px) {
  .cities-grid {
    grid-template-columns: 1fr;
  }
}

.city-name {
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-color);
  margin-bottom: 4px;
}

.aqi-value {
  font-size: 1.4em;
  font-weight: bold;
  padding: 8px;
  border-radius: 8px;
  text-align: center;
  margin-bottom: 4px;
}

.aqi-info {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
}

.info-item {
  font-size: 0.9em;
  color: #5f6368;
}

.info-item strong {
  display: block;
  color: var(--text-color);
  margin-bottom: 4px;
}

.city-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.aqi-legend {
  background: var(--card-background);
  padding: 20px;
  border-radius: var(--border-radius);
  margin: 20px 0;
}

.aqi-legend h3 {
  font-size: 1em;
  margin: 0 0 15px 0;
  color: var(--text-color);
}

.legend-item {
  display: flex;
  align-items: center;
  margin-bottom: 12px;
}

.color-box {
  width: 20px;
  height: 20px;
  border-radius: 4px;
  margin-right: 12px;
}

.color-box.good {
  background-color: #34a853;
}
.color-box.moderate {
  background-color: #fbbc04;
}
.color-box.unhealthy {
  background-color: #ea4335;
}
.color-box.very-unhealthy {
  background-color: #b31412;
}

.legend-text {
  flex: 1;
}

.legend-text .range {
  font-weight: 500;
  display: block;
  font-size: 0.9em;
}

.legend-text .desc {
  color: #5f6368;
  font-size: 0.85em;
}

.pollutants-info {
  background: var(--card-background);
  padding: 20px;
  border-radius: var(--border-radius);
  margin: 20px 0;
}

.pollutants-info h3 {
  font-size: 1em;
  margin: 0 0 15px 0;
  color: var(--text-color);
}

.pollutant-item {
  margin-bottom: 15px;
}

.pollutant-item h4 {
  font-size: 0.9em;
  margin: 0 0 5px 0;
  color: var(--primary-color);
}

.pollutant-item p {
  margin: 0;
  font-size: 0.85em;
  color: #5f6368;
  line-height: 1.4;
}

.sidebar::-webkit-scrollbar,
.cities-grid-container::-webkit-scrollbar {
  width: 6px;
}

.sidebar::-webkit-scrollbar-track,
.cities-grid-container::-webkit-scrollbar-track {
  background: transparent;
}

.sidebar::-webkit-scrollbar-thumb,
.cities-grid-container::-webkit-scrollbar-thumb {
  background: rgba(0, 0, 0, 0.1);
  border-radius: 10px;
  transition: background 0.2s ease;
}

.sidebar::-webkit-scrollbar-thumb:hover,
.cities-grid-container::-webkit-scrollbar-thumb:hover {
  background: rgba(0, 0, 0, 0.2);
}

.sidebar:hover::-webkit-scrollbar-thumb,
.cities-grid-container:hover::-webkit-scrollbar-thumb {
  background: rgba(0, 0, 0, 0.15);
}

.sidebar,
.cities-grid-container {
  scrollbar-width: thin;
  scrollbar-color: rgba(0, 0, 0, 0.1) transparent;
}

.sidebar,
.cities-grid-container {
  scroll-behavior: smooth;
}

.filter-section {
  background: var(--background-color);
  padding: 15px;
  border-radius: 12px;
  margin-bottom: 20px;
}

.select-wrapper {
  position: relative;
  margin-bottom: 10px;
}

.select-wrapper:last-child {
  margin-bottom: 0;
}

.select-wrapper i {
  position: absolute;
  left: 12px;
  top: 50%;
  transform: translateY(-50%);
  color: #5f6368;
  font-size: 0.9em;
  pointer-events: none;
}

.time-filter {
  width: 100%;
  padding: 10px 12px 10px 35px;
  border: 1px solid #e8eaed;
  border-radius: 8px;
  font-size: 0.95em;
  color: var(--text-color);
  background: var(--card-background);
  cursor: pointer;
  appearance: none;
  -webkit-appearance: none;
  transition: all 0.2s ease;
}

.time-filter:hover {
  border-color: #dadce0;
  background: #f8f9fa;
}

.time-filter:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 2px rgba(26, 115, 232, 0.1);
}

.select-wrapper::after {
  content: "";
  position: absolute;
  right: 12px;
  top: 50%;
  transform: translateY(-50%);
  border-left: 5px solid transparent;
  border-right: 5px solid transparent;
  border-top: 5px solid #5f6368;
  pointer-events: none;
}

.loading-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(255, 255, 255, 0.9);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  z-index: 9999;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s ease;
}

.loading-overlay.active {
  opacity: 1;
  visibility: visible;
}

.loading-spinner {
  width: 50px;
  height: 50px;
  border: 3px solid #f3f3f3;
  border-top: 3px solid var(--primary-color);
  border-radius: 50%;
  animation: spin 0.3s linear infinite;
  margin-bottom: 15px;
}

.loading-text {
  color: var(--text-color);
  font-size: 1.1em;
  font-weight: 500;
}

@keyframes spin {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

@media (max-width: 768px) {
  .wrapper {
    flex-direction: column;
  }

  .sidebar {
    width: 100%;
    height: auto;
    position: relative;
    border-right: none;
    border-bottom: 1px solid rgba(0, 0, 0, 0.08);
  }

  .main-content {
    margin-left: 0;
    padding: 16px;
  }

  .chart-section {
    height: auto;
    min-height: 250px;
    max-height: 400px;
    margin: 0 -16px;
    padding: 12px;
    border-radius: 0;
    background: var(--card-background);
    box-shadow: none;
    position: relative;
  }

  .chart-section::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: rgba(0, 0, 0, 0.08);
  }

  canvas#aqiChart {
    width: 100% !important;
    height: 100% !important;
    max-height: 350px;
  }

  .cities-grid-container {
    margin-top: 0;
    padding: 16px;
    max-height: none;
    overflow: visible;
  }

  .cities-grid {
    display: flex;
    flex-direction: column;
    gap: 12px;
    padding: 0;
  }

  .city-card {
    margin: 0;
    border-radius: 12px;
    background: var(--card-background);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
  }

  .city-card-header {
    padding: 12px;
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
  }

  .header-left {
    margin: 0;
    display: flex;
    align-items: center;
    gap: 12px;
  }

  .aqi-value {
    font-size: 1.5em;
    padding: 8px 12px;
    margin: 0;
    min-width: 45px;
    text-align: center;
  }

  .city-name {
    font-size: 1.1em;
    margin: 0;
  }

  .city-card-content {
    padding: 12px;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 8px;
  }

  .info-item {
    padding: 8px;
    flex-direction: row;
    align-items: center;
    gap: 8px;
    background: rgba(0, 0, 0, 0.02);
    border-radius: 8px;
  }

  .info-item i {
    font-size: 16px;
    margin: 0;
  }

  .update-time {
    padding: 8px 12px;
    font-size: 0.8em;
    color: #666;
    text-align: right;
    border-top: 1px solid rgba(0, 0, 0, 0.05);
  }
}

/* Thêm styles cho màn hình siêu nhỏ */
@media (max-width: 375px) {
  .chart-section {
    min-height: 200px;
  }

  canvas#aqiChart {
    max-height: 250px;
  }

  .city-card-content {
    grid-template-columns: 1fr;
  }

  .info-item {
    justify-content: space-between;
  }
}

.info-item {
  display: flex;
  align-items: center;
  font-size: 16px;
  gap: 8px;
}

.info-item i {
  font-size: 18px;
  width: 24px;
}

.info-item.pollutant i {
  color: #e74c3c; 
}

.info-item.wind i {
  color: #95a5a6; /
}

.info-item.humidity i {
  color: #3498db; 
}

.info-item.concentration i {
  color: #9b59b6; 
}