:root {
  /* Colors - accessible, Russian-inspired */
  --color-bg-primary: #f8f9fa;
  --color-bg-secondary: #ffffff;
  --color-bg-tertiary: #f1f3f5;
  --color-text-primary: #212529;
  --color-text-secondary: #495057;
  --color-text-muted: #6c757d;
  --color-accent-blue: #0d6efd;
  --color-accent-green: #198754;
  --color-accent-yellow: #ffc107;
  --color-accent-red: #dc3545;
  --color-border: #dee2e6;
  --color-shadow: 0 2px 4px rgba(0,0,0,0.05);

  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;

  /* Border radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;

  /* Fonts */
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'Courier New', Courier, monospace;

  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-medium: 0.25s ease;
}

/* Reset and base styles */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-sans);
  background-color: var(--color-bg-primary);
  color: var(--color-text-primary);
  line-height: 1.5;
}

/* Utility classes */
.visually-hidden {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

.hidden {
  display: none !important;
}

.text-center {
  text-align: center;
}

.text-right {
  text-align: right;
}

.font-bold {
  font-weight: 600;
}

.flex {
  display: flex;
}

.flex-col {
  flex-direction: column;
}

.items-center {
  align-items: center;
}

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

.gap-2 {
  gap: var(--spacing-sm);
}

.gap-4 {
  gap: var(--spacing-md);
}

.gap-6 {
  gap: var(--spacing-lg);
}

/* Layout */
.header {
  background-color: var(--color-bg-secondary);
  border-bottom: 1px solid var(--color-border);
  padding: var(--spacing-lg) var(--spacing-md);
  box-shadow: var(--color-shadow);
}

.header-content {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.header-title {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--color-text-primary);
}

.header-meta {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

.header-updated {
  font-weight: 500;
}

.header-age {
  font-style: italic;
}

.main {
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--spacing-md);
}

.section-title {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  color: var(--color-text-primary);
  padding: var(--spacing-sm) 0;
  border-bottom: 2px solid var(--color-border);
}

/* Route section */
.route-card {
  background-color: var(--color-bg-secondary);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  box-shadow: var(--color-shadow);
  border: 1px solid var(--color-border);
}

.route-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: var(--spacing-md);
}

.route-item {
  display: flex;
  flex-direction: column;
}

.route-label {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  margin-bottom: var(--spacing-xs);
}

.route-value {
  font-size: 1rem;
  font-weight: 500;
  color: var(--color-text-primary);
  word-break: break-word;
}

.status-badge {
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  text-transform: capitalize;
}

.status-badge.active {
  background-color: rgba(25, 135, 84, 0.1);
  color: var(--color-accent-green);
}

.status-badge.inactive {
  background-color: rgba(220, 53, 69, 0.1);
  color: var(--color-accent-red);
}

.status-badge.unknown {
  background-color: rgba(108, 117, 125, 0.1);
  color: var(--color-text-muted);
}

/* Accounts section */
.accounts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-lg);
}

.account-card {
  background-color: var(--color-bg-secondary);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  box-shadow: var(--color-shadow);
  border: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  height: 100%;
}

.account-header {
  margin-bottom: var(--spacing-md);
  padding-bottom: var(--spacing-sm);
  border-bottom: 1px solid var(--color-border);
}

.account-name {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--color-text-primary);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.account-plan {
  font-size: 0.875rem;
  padding: var(--spacing-xs) var(--spacing-sm);
  background-color: var(--color-bg-tertiary);
  border-radius: var(--radius-sm);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.plan-plus {
  background-color: rgba(13, 116, 253, 0.1);
  color: var(--color-accent-blue);
}

.plan-free {
  background-color: rgba(108, 117, 125, 0.1);
  color: var(--color-text-muted);
}

.account-status {
  margin-top: auto;
  padding-top: var(--spacing-sm);
  border-top: 1px solid var(--color-border);
}

.status-indicator {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: 0.875rem;
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  display: inline-block;
}

.status-dot.active {
  background-color: var(--color-accent-green);
}

.status-dot.inactive {
  background-color: var(--color-accent-red);
}

.status-dot.unknown {
  background-color: var(--color-text-muted);
}

.windows-grid {
  margin-top: var(--spacing-md);
  flex-grow: 1;
}

.window-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-sm) 0;
  border-bottom: 1px solid var(--color-border);
}

.window-item:last-child {
  border-bottom: none;
}

.window-label {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
}

.window-value {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-primary);
  min-width: 60px;
  text-align: right;
}

/* Countdown styling */
.countdown {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  background-color: var(--color-bg-tertiary);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-sm);
  display: inline-block;
}

/* History section */
.chart-container {
  background-color: var(--color-bg-secondary);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  box-shadow: var(--color-shadow);
  border: 1px solid var(--color-border);
}

.chart-controls {
  margin-bottom: var(--spacing-md);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
}

.chart-controls label {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
}

.chart-controls select {
  padding: var(--spacing-xs) var(--spacing-sm);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background-color: var(--color-bg-secondary);
  font-size: 0.875rem;
  min-width: 150px;
  cursor: pointer;
}

.chart-wrapper {
  position: relative;
  height: 300px;
  overflow: hidden;
}

.chart-loading,
.chart-empty {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  text-align: center;
  color: var(--color-text-muted);
  font-style: italic;
  padding: var(--spacing-md);
  background-color: rgba(255, 255, 255, 0.8);
  border-radius: var(--radius-sm);
}

.chart-empty {
  display: none;
}

/* Events section */
.events-list {
  list-style: none;
  max-height: 200px;
  overflow-y: auto;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background-color: var(--color-bg-secondary);
  padding: var(--spacing-sm);
}

.events-list li {
  padding: var(--spacing-sm) 0;
  border-bottom: 1px solid var(--color-border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.875rem;
}

.events-list li:last-child {
  border-bottom: none;
}

.event-time {
  color: var(--color-text-muted);
  font-family: var(--font-mono);
  font-size: 0.75rem;
}

.event-description {
  flex-grow: 1;
  margin: 0 var(--spacing-sm);
  word-break: break-word;
}

.event-type {
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  font-weight: 500;
  text-transform: capitalize;
}

.event-type.limit_exceeded {
  background-color: rgba(220, 53, 69, 0.1);
  color: var(--color-accent-red);
}

.event_type.connected {
  background-color: rgba(25, 135, 84, 0.1);
  color: var(--color-accent-green);
}

.event_type.warning {
  background-color: rgba(255, 193, 7, 0.1);
  color: var(--color-accent-yellow);
}

/* Responsive design */
@media (max-width: 768px) {
  .header-content {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .header-meta {
    align-self: flex-end;
  }
  
  .route-grid {
    grid-template-columns: 1fr;
  }
  
  .accounts-grid {
    grid-template-columns: 1fr;
  }
}

/* Print styles */
@media print {
  body {
    background-color: white;
  }
  
  .header,
  .footer {
    background-color: white;
    box-shadow: none;
  }
  
  .card,
  .chart-container {
    box-shadow: none;
    border: 1px solid #ddd;
    page-break-inside: avoid;
  }
}