:root {
  /* Premium Color Palette (HSL for dynamic lighting) */
  --hue-primary: 220;
  --color-primary: hsl(var(--hue-primary), 90%, 55%);
  --color-primary-hover: hsl(var(--hue-primary), 90%, 50%);
  --color-primary-soft: hsl(var(--hue-primary), 90%, 95%);
  
  --color-success: hsl(150, 70%, 45%);
  --color-warning: hsl(35, 90%, 55%);
  --color-danger: hsl(350, 80%, 55%);
  
  /* Light Theme Colors */
  --bg-app: hsl(220, 20%, 98%);
  --bg-surface: hsl(0, 0%, 100%);
  --bg-surface-hover: hsl(220, 15%, 96%);
  
  --text-main: hsl(220, 30%, 15%);
  --text-muted: hsl(220, 15%, 45%);
  
  --border-color: hsl(220, 15%, 90%);
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
  --shadow-lg: 0 12px 24px rgba(0,0,0,0.12);
  
  /* Glassmorphism */
  --glass-bg: rgba(255, 255, 255, 0.8);
  --glass-border: rgba(255, 255, 255, 0.4);
  
  /* Typography */
  --font-sans: 'Inter', system-ui, sans-serif;
  --font-display: 'Outfit', system-ui, sans-serif;
  
  /* Metrics */
  --sidebar-width: 260px;
  --header-height: 64px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.dark-theme {
  --bg-app: hsl(220, 25%, 10%);
  --bg-surface: hsl(220, 25%, 14%);
  --bg-surface-hover: hsl(220, 25%, 18%);
  
  --text-main: hsl(0, 0%, 98%);
  --text-muted: hsl(220, 15%, 65%);
  
  --border-color: hsl(220, 25%, 20%);
  --color-primary-soft: hsl(var(--hue-primary), 90%, 20%);
  
  --glass-bg: rgba(20, 25, 35, 0.8);
  --glass-border: rgba(255, 255, 255, 0.05);
  
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.2);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.3);
  --shadow-lg: 0 12px 24px rgba(0,0,0,0.4);
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-app);
  color: var(--text-main);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 600;
  letter-spacing: -0.02em;
}

/* App Layout */
.app-layout {
  display: flex;
  height: 100vh;
  overflow: hidden;
}

/* Sidebar */
.app-sidebar {
  width: var(--sidebar-width);
  background-color: var(--bg-surface);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  transition: var(--transition);
  z-index: 100;
}

.sidebar-header {
  height: var(--header-height);
  display: flex;
  align-items: center;
  padding: 0 24px;
  border-bottom: 1px solid var(--border-color);
}

.logo {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--color-primary);
}

.sidebar-nav {
  flex: 1;
  overflow-y: auto;
  padding: 16px 12px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 12px;
  color: var(--text-muted);
  text-decoration: none;
  border-radius: var(--radius-md);
  font-weight: 500;
  transition: var(--transition);
  position: relative;
}

.nav-link:hover {
  background-color: var(--bg-surface-hover);
  color: var(--text-main);
}

.nav-link.active {
  background-color: var(--color-primary-soft);
  color: var(--color-primary);
}

.badge {
  background-color: var(--color-danger);
  color: white;
  font-size: 0.75rem;
  padding: 2px 6px;
  border-radius: 99px;
  margin-left: auto;
}

.sidebar-footer {
  padding: 16px;
  border-top: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.user-profile {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
  flex: 1;
}

.avatar {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  object-fit: cover;
}

.user-info {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.user-name {
  font-size: 0.875rem;
  font-weight: 600;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.user-role {
  font-size: 0.75rem;
  color: var(--text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* Main Content */
.app-main {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
  overflow: hidden;
}

.app-header {
  height: var(--header-height);
  background-color: var(--glass-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
  z-index: 10;
}

.header-title {
  font-size: 1.25rem;
  font-weight: 600;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

.icon-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-size: 1.25rem;
  cursor: pointer;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
}

.icon-btn:hover {
  background-color: var(--bg-surface-hover);
  color: var(--text-main);
}

.network-status {
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  color: white;
  transition: var(--transition);
}

.network-status.online {
  background-color: var(--color-success);
}
.network-status.offline {
  background-color: var(--color-danger);
  animation: pulse 2s infinite;
}

.app-content {
  flex: 1;
  overflow-y: auto;
  padding: 24px;
  position: relative;
}

/* Mobile Adjustments */
.mobile-only {
  display: none;
}

@media (max-width: 768px) {
  .mobile-only {
    display: flex;
  }
  
  .app-sidebar {
    position: fixed;
    left: calc(var(--sidebar-width) * -1);
    height: 100vh;
    box-shadow: var(--shadow-xl);
  }
  
  .app-sidebar.open {
    left: 0;
  }
  
  .app-content {
    padding: 16px;
  }
}

/* Utilities & Animations */
@keyframes pulse {
  0% { opacity: 1; }
  50% { opacity: 0.5; }
  100% { opacity: 1; }
}

.fade-enter {
  animation: fadeIn 0.3s ease forwards;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Card UI */
.card {
  background-color: var(--bg-surface);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  padding: 20px;
  transition: var(--transition);
}

.card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary-soft);
}

/* Toasts */
.toast-container {
  position: fixed;
  bottom: 24px;
  right: 24px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  z-index: 1000;
}

.toast {
  background-color: var(--bg-surface);
  color: var(--text-main);
  padding: 16px;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  border-left: 4px solid var(--color-primary);
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 300px;
  animation: slideInRight 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.toast.success { border-left-color: var(--color-success); }
.toast.error { border-left-color: var(--color-danger); }
.toast.warning { border-left-color: var(--color-warning); }

@keyframes slideInRight {
  from { transform: translateX(100%); opacity: 0; }
  to { transform: translateX(0); opacity: 1; }
}

/* Buttons */
.btn-primary, .btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 18px;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 500;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: var(--transition);
  text-decoration: none;
}

.btn-primary {
  background-color: var(--color-primary);
  color: white;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.btn-primary:hover {
  background-color: var(--color-primary-hover);
  box-shadow: 0 4px 8px rgba(0,0,0,0.15);
}

.btn-secondary {
  background-color: var(--bg-surface-hover);
  color: var(--text-main);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background-color: var(--border-color);
}

.btn-sm {
  padding: 6px 12px;
  font-size: 0.85rem;
  border-radius: 6px;
}