:root {
  /* === Palette: Industrial, Reliable, Intelligent === */

  /* Backgrounds */
  --color-bg: #0f1115;
  --color-surface: #161a20;
  --color-surface-elevated: #1e232b;
  --color-surface-muted: #252b35;
  --color-surface-hover: #2a313c;
  --color-surface-active: #313a47;

  /* Primary / Brand */
  --color-primary: #3b82f6;
  --color-primary-light: #60a5fa;
  --color-primary-dark: #2563eb;
  --color-primary-subtle: rgba(59, 130, 246, 0.12);

  /* Concrete greys */
  --color-concrete-50: #f8f9fa;
  --color-concrete-100: #f1f3f5;
  --color-concrete-200: #e9ecef;
  --color-concrete-300: #dee2e6;
  --color-concrete-400: #ced4da;
  --color-concrete-500: #adb5bd;
  --color-concrete-600: #868e96;
  --color-concrete-700: #495057;
  --color-concrete-800: #343a40;
  --color-concrete-900: #212529;

  /* Text */
  --color-text: #f1f5f9;
  --color-text-secondary: #94a3b8;
  --color-text-muted: #64748b;
  --color-text-inverse: #0f1115;

  /* Semantic status */
  --color-success: #22c55e;
  --color-success-subtle: rgba(34, 197, 94, 0.12);
  --color-warning: #f59e0b;
  --color-warning-subtle: rgba(245, 158, 11, 0.12);
  --color-danger: #ef4444;
  --color-danger-subtle: rgba(239, 68, 68, 0.12);
  --color-info: #3b82f6;
  --color-info-subtle: rgba(59, 130, 246, 0.12);

  /* AI */
  --color-ai: #8b5cf6;
  --color-ai-light: #a78bfa;
  --color-ai-subtle: rgba(139, 92, 246, 0.12);

  /* Borders & Dividers */
  --color-border: rgba(148, 163, 184, 0.14);
  --color-border-strong: rgba(148, 163, 184, 0.24);
  --color-divider: rgba(148, 163, 184, 0.1);

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.25);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -2px rgba(0, 0, 0, 0.2);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.35), 0 4px 6px -4px rgba(0, 0, 0, 0.25);
  --shadow-glow-ai: 0 0 0 1px rgba(139, 92, 246, 0.35), 0 0 20px rgba(139, 92, 246, 0.15);

  /* Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-full: 9999px;

  /* Spacing scale */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 20px;
  --space-6: 24px;
  --space-8: 32px;
  --space-10: 40px;

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', Consolas, monospace;

  --text-xs: 11px;
  --text-sm: 12px;
  --text-base: 13px;
  --text-md: 14px;
  --text-lg: 16px;
  --text-xl: 18px;
  --text-2xl: 22px;
  --text-3xl: 28px;

  --font-regular: 400;
  --font-medium: 500;
  --font-semibold: 600;
  --font-bold: 700;

  --leading-tight: 1.25;
  --leading-normal: 1.5;
  --leading-relaxed: 1.65;

  /* Layout */
  --sidebar-width: 240px;
  --sidebar-collapsed: 64px;
  --topbar-height: 56px;
  --content-max-width: 1600px;

  /* Transitions */
  --transition-fast: 120ms ease;
  --transition-base: 180ms ease;
  --transition-slow: 240ms ease;

  /* Z-index */
  --z-base: 1;
  --z-sticky: 100;
  --z-dropdown: 200;
  --z-modal: 300;
  --z-toast: 400;
}