:root {
  /* Colors - Modern Slate & Curated HSL Accents (getdesign.md spec) */
  --color-bg: #ffffff;
  --color-surface: #f8fafc;
  --color-surface-hover: #f1f5f9;
  --color-card: #ffffff;
  --color-border: #e2e8f0;
  --color-border-hover: #cbd5e1;
  --color-border-input: #cbd5e1;
  --color-border-focus: #2563eb;
  
  --color-text: #0f172a;
  --color-text-secondary: #334155;
  --color-text-muted: #64748b;
  --color-text-subtle: #94a3b8;
  
  --color-accent: #2563eb;
  --color-accent-hover: #1d4ed8;
  --color-accent-active: #1e40af;
  --color-accent-subtle: #eff6ff;
  --color-on-accent: #ffffff;
  
  --color-danger: #ef4444;
  --color-danger-hover: #dc2626;
  --color-danger-subtle: #fef2f2;
  --color-danger-border: #fecaca;
  
  --color-success: #10b981;
  --color-success-hover: #059669;
  --color-success-subtle: #ecfdf5;
  --color-success-border: #a7f3d0;
  
  --color-warning: #f59e0b;
  --color-warning-hover: #d97706;
  --color-warning-subtle: #fffbeb;
  --color-warning-border: #fde68a;

  --color-purple: #8b5cf6;
  --color-purple-subtle: #f5f3ff;

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;

  /* Font sizes & line heights with tnum support */
  --text-2xs: 11px;
  --line-2xs: 16px;
  --text-xs: 12.5px;
  --line-xs: 18px;
  --text-sm: 13.5px;
  --line-sm: 20px;
  --text-base: 14.5px;
  --line-base: 22px;
  --text-md: 16.5px;
  --line-md: 24px;
  --text-lg: 19px;
  --line-lg: 26px;
  --text-xl: 24px;
  --line-xl: 32px;
  --text-display: 32px;
  --line-display: 40px;

  /* Spacing Scale - Clean 8pt/4pt standard (KeepSimple UX Core) */
  --space-0: 0px;
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 20px;
  --space-6: 24px;
  --space-7: 28px;
  --space-8: 32px;
  --space-9: 40px;
  --space-10: 48px;
  --space-11: 64px;

  /* Border radius */
  --radius-xs: 4px;
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-pill: 9999px;

  /* Premium Elevation Shadows */
  --shadow-xs: 0 1px 2px 0 rgba(15, 23, 42, 0.04);
  --shadow-sm: 0 1px 3px 0 rgba(15, 23, 42, 0.08), 0 1px 2px -1px rgba(15, 23, 42, 0.04);
  --shadow-card: 0 1px 3px 0 rgba(15, 23, 42, 0.06), 0 1px 2px -1px rgba(15, 23, 42, 0.04);
  --shadow-card-hover: 0 10px 15px -3px rgba(15, 23, 42, 0.08), 0 4px 6px -4px rgba(15, 23, 42, 0.04);
  --shadow-dropdown: 0 10px 25px -5px rgba(15, 23, 42, 0.12), 0 8px 10px -6px rgba(15, 23, 42, 0.06);
  --shadow-popover: 0 20px 25px -5px rgba(15, 23, 42, 0.14), 0 8px 10px -6px rgba(15, 23, 42, 0.08);

  /* Motion */
  --motion-fast: 120ms;
  --motion-base: 200ms;
  --motion-ease: cubic-bezier(0.16, 1, 0.3, 1);
}