/* ============================================
   THEME SYSTEM — CSS Custom Properties
   Light theme (default) + Dark theme
   ============================================ */

:root,
[data-theme="light"] {
  /* Background */
  --bg-primary: #F8F9FC;
  --bg-secondary: #FFFFFF;
  --bg-tertiary: #F0F1F5;
  --bg-hover: #ECEDF2;
  --bg-active: #E4E5EC;
  --bg-overlay: rgba(15, 16, 23, 0.4);
  --bg-glass: rgba(255, 255, 255, 0.72);

  /* Surface (cards, panels) */
  --surface-primary: #FFFFFF;
  --surface-raised: #FFFFFF;
  --surface-sunken: #F4F5F9;

  /* Text */
  --text-primary: #1A1B2E;
  --text-secondary: #6B7194;
  --text-tertiary: #A0A5BD;
  --text-inverse: #F0F1F5;
  --text-on-accent: #FFFFFF;

  /* Borders */
  --border-primary: #E2E4ED;
  --border-secondary: #ECEDF2;
  --border-focus: #4F46E5;

  /* Accent */
  --accent: #4F46E5;
  --accent-hover: #4338CA;
  --accent-light: #EEF2FF;
  --accent-muted: rgba(79, 70, 229, 0.1);

  /* Status */
  --success: #10B981;
  --success-light: #ECFDF5;
  --warning: #F59E0B;
  --warning-light: #FFFBEB;
  --danger: #EF4444;
  --danger-light: #FEF2F2;
  --info: #3B82F6;
  --info-light: #EFF6FF;

  /* Priority colors */
  --priority-urgent: #EF4444;
  --priority-high: #F59E0B;
  --priority-medium: #4F46E5;
  --priority-low: #A0A5BD;

  /* Shadows */
  --shadow-xs: 0 1px 2px rgba(15, 16, 23, 0.04);
  --shadow-sm: 0 2px 4px rgba(15, 16, 23, 0.06);
  --shadow-md: 0 4px 12px rgba(15, 16, 23, 0.08);
  --shadow-lg: 0 8px 24px rgba(15, 16, 23, 0.10);
  --shadow-xl: 0 16px 48px rgba(15, 16, 23, 0.12);
  --shadow-card: 0 1px 3px rgba(15, 16, 23, 0.04), 0 1px 2px rgba(15, 16, 23, 0.06);
  --shadow-card-hover: 0 8px 24px rgba(15, 16, 23, 0.10), 0 2px 4px rgba(15, 16, 23, 0.04);
  --shadow-modal: 0 24px 64px rgba(15, 16, 23, 0.16);

  /* Radius */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --radius-xl: 20px;
  --radius-full: 9999px;

  /* Spacing */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 20px;
  --space-6: 24px;
  --space-8: 32px;
  --space-10: 40px;
  --space-12: 48px;

  /* Column */
  --column-width: 320px;
  --column-gap: 20px;

  /* Z-index */
  --z-dropdown: 100;
  --z-sticky: 200;
  --z-modal-backdrop: 300;
  --z-modal: 400;
  --z-toast: 500;
  --z-drag: 600;

  /* Transition */
  --transition-fast: 0.15s ease;
  --transition-base: 0.2s ease;
  --transition-slow: 0.3s ease;
  --transition-spring: 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);

  /* Scrollbar */
  --scrollbar-width: 6px;
  --scrollbar-track: transparent;
  --scrollbar-thumb: #D1D5DB;
  --scrollbar-thumb-hover: #9CA3AF;
}

/* ============================================
   DARK THEME
   ============================================ */

[data-theme="dark"] {
  /* Background */
  --bg-primary: #0F1017;
  --bg-secondary: #151623;
  --bg-tertiary: #1A1B2E;
  --bg-hover: #222338;
  --bg-active: #2A2C42;
  --bg-overlay: rgba(0, 0, 0, 0.6);
  --bg-glass: rgba(21, 22, 35, 0.8);

  /* Surface */
  --surface-primary: #1A1B2E;
  --surface-raised: #1F2037;
  --surface-sunken: #12131F;

  /* Text */
  --text-primary: #F0F1F5;
  --text-secondary: #8B90AB;
  --text-tertiary: #5D6180;
  --text-inverse: #1A1B2E;
  --text-on-accent: #FFFFFF;

  /* Borders */
  --border-primary: #2A2C3E;
  --border-secondary: #222338;
  --border-focus: #6366F1;

  /* Accent */
  --accent: #6366F1;
  --accent-hover: #818CF8;
  --accent-light: rgba(99, 102, 241, 0.15);
  --accent-muted: rgba(99, 102, 241, 0.08);

  /* Status */
  --success: #34D399;
  --success-light: rgba(52, 211, 153, 0.12);
  --warning: #FBBF24;
  --warning-light: rgba(251, 191, 36, 0.12);
  --danger: #F87171;
  --danger-light: rgba(248, 113, 113, 0.12);
  --info: #60A5FA;
  --info-light: rgba(96, 165, 250, 0.12);

  /* Shadows */
  --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.2);
  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.25);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.35);
  --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.4);
  --shadow-card: 0 1px 3px rgba(0, 0, 0, 0.2), 0 1px 2px rgba(0, 0, 0, 0.15);
  --shadow-card-hover: 0 8px 24px rgba(0, 0, 0, 0.35), 0 2px 4px rgba(0, 0, 0, 0.2);
  --shadow-modal: 0 24px 64px rgba(0, 0, 0, 0.5);

  /* Scrollbar */
  --scrollbar-thumb: #3A3C52;
  --scrollbar-thumb-hover: #4A4D68;
}