:root {
  /* Primary */
  --primary: #3182ce;
  --primary-dark: #2c5282;
  --primary-light: #bee3f8;
  --primary-bg: #ebf8ff;

  /* Secondary */
  --secondary: #805ad5;
  --secondary-dark: #6b46c1;
  --secondary-light: #e9d8fd;

  /* Status */
  --success: #38a169;
  --success-bg: #f0fff4;
  --warning: #d69e2e;
  --warning-bg: #fffff0;
  --error: #e53e3e;
  --error-bg: #fff5f5;
  --info: #3182ce;
  --info-bg: #ebf8ff;

  /* Backgrounds */
  --bg-primary: #ffffff;
  --bg-secondary: #f7fafc;
  --bg-tertiary: #edf2f7;
  --bg-elevated: #ffffff;

  /* Text */
  --text-primary: #1a202c;
  --text-secondary: #4a5568;
  --text-tertiary: #a0aec0;
  --text-inverse: #ffffff;

  /* Borders */
  --border-color: #e2e8f0;
  --border-light: #edf2f7;

  /* Spacing */
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-2xl: 48px;

  /* Typography */
  --font-xs: 0.75rem;
  --font-sm: 0.875rem;
  --font-md: 1rem;
  --font-lg: 1.125rem;
  --font-xl: 1.25rem;
  --font-2xl: 1.5rem;
  --font-3xl: 2rem;

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

  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;
  --radius-xl: 12px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.07);
  --shadow-lg: 0 10px 15px rgba(0,0,0,0.1);
  --shadow-xl: 0 20px 25px rgba(0,0,0,0.15);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 200ms ease;
  --transition-slow: 300ms ease;

  /* Layout */
  --sidebar-width: 250px;
  --header-height: 0px;
}

/* Dark Mode */
[data-theme="dark"] {
  --bg-primary: #1a202c;
  --bg-secondary: #2d3748;
  --bg-tertiary: #4a5568;
  --bg-elevated: #2d3748;

  --text-primary: #f7fafc;
  --text-secondary: #cbd5e0;
  --text-tertiary: #718096;

  --border-color: #4a5568;
  --border-light: #2d3748;

  --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.4);
  --shadow-lg: 0 10px 15px rgba(0,0,0,0.5);
}

/* Reset */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  font-size: var(--font-md);
  color: var(--text-primary);
  background: var(--bg-secondary);
  line-height: 1.5;
}

a { color: var(--primary); text-decoration: none; }
a:hover { color: var(--primary-dark); }