:root {
  --bg-dark: #0f172a;
  --bg-card: rgba(30, 41, 59, 0.7);
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --accent-blue: #3b82f6;
  --accent-cyan: #22d3ee;
  --accent-green: #10b981;
  --accent-red: #ef4444;
  --border-color: rgba(255, 255, 255, 0.1);
}

body {
  margin: 0;
  font-family: 'Inter', system-ui, sans-serif;
  background-color: var(--bg-dark);
  color: var(--text-main);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Glassmorphism Header */
header {
  background: rgba(15, 23, 42, 0.8);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  padding: 1.5rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: sticky;
  top: 0;
  z-index: 10;
}

header h1 {
  margin: 0;
  font-size: 1.5rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.dashboard-container {
  padding: 2rem;
  flex: 1;
  display: grid;
  grid-template-columns: 1fr 350px;
  gap: 2rem;
  max-width: 1400px;
  margin: 0 auto;
  width: 100%;
  box-sizing: border-box;
}

/* Cards */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 1.5rem;
  backdrop-filter: blur(10px);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  overflow: hidden;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.5);
  border-color: rgba(255, 255, 255, 0.2);
}

.card-title {
  margin-top: 0;
  font-size: 1.1rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

/* Device List Grid */
.device-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
}

.device-item {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid rgba(255, 255, 255, 0.05);
  border-radius: 12px;
  padding: 1rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

.device-item:hover, .device-item.active {
  background: rgba(34, 211, 238, 0.1);
  border-color: var(--accent-cyan);
}

.status-indicator {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  display: inline-block;
  margin-right: 8px;
}

.status-online { background: var(--accent-green); box-shadow: 0 0 10px var(--accent-green); }
.status-offline { background: var(--accent-red); }

/* Chart Container */
.chart-container {
  height: 300px;
  width: 100%;
}

/* OTA Section */
.ota-panel {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.ota-form group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

input, select, button {
  font-family: inherit;
  background: rgba(0, 0, 0, 0.2);
  border: 1px solid var(--border-color);
  color: white;
  padding: 0.75rem 1rem;
  border-radius: 8px;
  outline: none;
  transition: border-color 0.2s;
}

input:focus, select:focus {
  border-color: var(--accent-blue);
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent-blue), #2563eb);
  border: none;
  font-weight: 600;
  cursor: pointer;
  transition: opacity 0.2s, transform 0.1s;
}

.btn-primary:hover {
  opacity: 0.9;
}
.btn-primary:active {
  transform: scale(0.98);
}

/* Values Highlight */
.metric-value {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--text-main);
  margin: 1rem 0;
}
.metric-label {
  font-size: 0.875rem;
  color: var(--text-muted);
}