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

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  min-height: 100vh;
  padding: 2rem;
  display: flex;
  align-items: center;
  justify-content: center;
}

.container {
  width: 100%;
  max-width: 1200px;
}

h1 {
  text-align: center;
  color: white;
  margin-bottom: 2rem;
  font-size: 2.5rem;
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
}

.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.5rem;
  padding: 0 1rem;
}

.sensor-card {
  background: white;
  border-radius: 20px;
  padding: 2rem;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  position: relative;
  overflow: hidden;
}

.sensor-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 5px;
  background: linear-gradient(90deg, #667eea, #764ba2);
}

.sensor-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 15px 40px rgba(0, 0, 0, 0.3);
}

.device-label {
  font-size: 0.85rem;
  color: #666;
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 1rem;
  font-weight: 600;
}

.temperature {
  font-size: 4rem;
  font-weight: 700;
  color: #333;
  line-height: 1;
  margin: 1rem 0;
  background: linear-gradient(135deg, #667eea, #764ba2);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.humidity {
  font-size: 1.2rem;
  color: #888;
  margin-top: 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.timestamp {
  font-size: 1.0rem;
  color: #888;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-left: 2.0rem;
  margin-top: 1.0rem;
}

.humidity-icon {
  width: 20px;
  height: 20px;
  opacity: 0.6;
}

/* Responsive adjustments */
@media (max-width: 768px) {
  h1 {
    font-size: 2rem;
  }

  .cards-grid {
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
  }

  .temperature {
    font-size: 3rem;
  }

  .sensor-card {
    padding: 1.5rem;
  }
}

@media (max-width: 480px) {
  body {
    padding: 1rem;
  }

  h1 {
    font-size: 1.5rem;
  }

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

  .temperature {
    font-size: 2.5rem;
  }
}
.chart-container {
  background: white;
  border-radius: 20px;
  padding: 2rem;
  margin-top: 2rem;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
  position: relative;
}

.chart-container::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 5px;
  background: linear-gradient(90deg, #667eea, #764ba2);
  border-radius: 20px 20px 0 0;
}

.chart-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
  gap: 1rem;
}

.chart-container h2 {
  color: #333;
  font-size: 1.5rem;
  margin: 0;
}

.time-range-selector {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.time-range-btn {
  padding: 0.5rem 1rem;
  border: 2px solid #667eea;
  background: white;
  color: #667eea;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 600;
  transition: all 0.3s ease;
  font-size: 0.9rem;
}

.time-range-btn:hover {
  background: #667eea;
  color: white;
  transform: translateY(-2px);
  box-shadow: 0 4px 8px rgba(102, 126, 234, 0.3);
}

.time-range-btn.active {
  background: linear-gradient(135deg, #667eea, #764ba2);
  color: white;
  border-color: #764ba2;
}

@media (max-width: 768px) {
  .chart-container {
    padding: 1.5rem;
  }

  .chart-header {
    flex-direction: column;
    align-items: flex-start;
  }

  .chart-container h2 {
    font-size: 1.2rem;
  }

  .time-range-btn {
    padding: 0.4rem 0.8rem;
    font-size: 0.85rem;
  }
}