:root {
  --primary: #10b981;
  --primary-dark: #059669;
  --primary-light: #34d399;
  --accent-cyan: #06b6d4;
  --accent-amber: #f59e0b;
  --accent-rose: #f43f5e;
  --accent-violet: #8b5cf6;
  
  --bg-dark: #0b0f19;
  --card-bg: #131c2e;
  --card-border: #1e293b;
  --surface: #1e293b;
  --surface-hover: #293548;
  
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-dim: #64748b;
  
  --shadow-glow: 0 0 25px rgba(16, 185, 129, 0.25);
  --radius-lg: 20px;
  --radius-md: 14px;
  --radius-sm: 8px;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: 'Outfit', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

body {
  background-color: var(--bg-dark);
  color: var(--text-main);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}

/* Header & Nav */
header {
  background: rgba(19, 28, 46, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--card-border);
  position: sticky;
  top: 0;
  z-index: 100;
  padding: 0.85rem 1.5rem;
}

.nav-container {
  max-width: 1280px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text-main);
}

.brand-icon {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--primary), var(--accent-cyan));
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(16, 185, 129, 0.35);
  color: white;
  font-size: 1.25rem;
}

.brand-title {
  font-size: 1.25rem;
  font-weight: 800;
  letter-spacing: 0.5px;
  background: linear-gradient(135deg, #fff, var(--primary-light));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.badge-online {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  background: rgba(16, 185, 129, 0.15);
  color: var(--primary-light);
  border: 1px solid rgba(16, 185, 129, 0.3);
  padding: 0.35rem 0.75rem;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
}

.badge-dot {
  width: 8px;
  height: 8px;
  background-color: var(--primary);
  border-radius: 50%;
  box-shadow: 0 0 8px var(--primary);
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0% { transform: scale(0.95); opacity: 0.8; }
  50% { transform: scale(1.2); opacity: 1; }
  100% { transform: scale(0.95); opacity: 0.8; }
}

/* Main Container */
main {
  flex: 1;
  max-width: 1280px;
  width: 100%;
  margin: 0 auto;
  padding: 1.5rem;
}

/* Authentication Screen */
.auth-container {
  max-width: 440px;
  margin: 3rem auto;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: 2.5rem 2rem;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
}

.auth-header {
  text-align: center;
  margin-bottom: 2rem;
}

.auth-header h2 {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.form-group {
  margin-bottom: 1.25rem;
}

.form-group label {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.form-control {
  width: 100%;
  padding: 0.85rem 1rem;
  background: var(--bg-dark);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  color: var(--text-main);
  font-size: 0.95rem;
  transition: all 0.2s ease;
}

.form-control:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.2);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.85rem 1.5rem;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: all 0.2s ease;
  text-decoration: none;
}

.btn-primary {
  background: var(--primary);
  color: white;
  box-shadow: 0 4px 14px rgba(16, 185, 129, 0.35);
}

.btn-primary:hover {
  background: var(--primary-dark);
  transform: translateY(-1px);
}

.btn-outline {
  background: var(--surface);
  color: var(--text-main);
  border: 1px solid var(--card-border);
}

.btn-outline:hover {
  background: var(--surface-hover);
}

.btn-danger {
  background: rgba(244, 63, 94, 0.15);
  color: var(--accent-rose);
  border: 1px solid rgba(244, 63, 94, 0.3);
}

.btn-block {
  width: 100%;
}

.auth-tabs {
  display: flex;
  border-bottom: 1px solid var(--card-border);
  margin-bottom: 1.5rem;
}

.auth-tab {
  flex: 1;
  text-align: center;
  padding: 0.75rem;
  color: var(--text-muted);
  cursor: pointer;
  font-weight: 600;
  border-bottom: 2px solid transparent;
}

.auth-tab.active {
  color: var(--primary-light);
  border-bottom-color: var(--primary);
}

/* Dashboard Cards & Layout */
.dashboard-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.25rem;
  margin-bottom: 2rem;
}

.stat-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.stat-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}

.stat-icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
}

.stat-value {
  font-size: 1.85rem;
  font-weight: 700;
  color: var(--text-main);
}

.stat-label {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Device & Sensor Cards */
.sensor-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin-bottom: 2rem;
}

.sensor-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  transition: all 0.2s ease;
}

.sensor-card.alert {
  background: rgba(244, 63, 94, 0.12);
  border-color: var(--accent-rose);
  box-shadow: 0 0 15px rgba(244, 63, 94, 0.2);
}

.device-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.25rem;
  margin-bottom: 2rem;
}

.device-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: all 0.2s ease;
}

.device-card.active {
  border-color: rgba(16, 185, 129, 0.5);
  background: linear-gradient(135deg, rgba(16, 185, 129, 0.08), var(--card-bg));
}

/* Switch UI */
.switch {
  position: relative;
  display: inline-block;
  width: 52px;
  height: 28px;
}

.switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.slider {
  position: absolute;
  cursor: pointer;
  top: 0; left: 0; right: 0; bottom: 0;
  background-color: var(--surface);
  border: 1px solid var(--card-border);
  transition: .3s;
  border-radius: 34px;
}

.slider:before {
  position: absolute;
  content: "";
  height: 20px;
  width: 20px;
  left: 4px;
  bottom: 3px;
  background-color: var(--text-muted);
  transition: .3s;
  border-radius: 50%;
}

input:checked + .slider {
  background-color: var(--primary);
  border-color: var(--primary);
}

input:checked + .slider:before {
  transform: translateX(24px);
  background-color: white;
}

/* Modal */
.modal-overlay {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: 1.5rem;
}

.modal-content {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  max-width: 600px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
  padding: 2rem;
  box-shadow: 0 25px 50px rgba(0, 0, 0, 0.5);
}

/* Table */
.data-table {
  width: 100%;
  border-collapse: collapse;
}

.data-table th, .data-table td {
  padding: 1rem;
  text-align: left;
  border-bottom: 1px solid var(--card-border);
}

.data-table th {
  color: var(--text-muted);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}