/* ==============================================
   CSS Custom Properties / Variables
   Theme colors, typography, spacing, and layout
   ============================================== */

:root {
  /* ============================================
     Color Palette
     ============================================ */

  /* Primary Colors */
  --color-primary-dark: #0E3A3A;
  --color-primary-light: #F8F9F7;

  /* Accent Colors */
  --color-accent-yellow: #F4C430;
  --color-accent-soft-yellow: #F6D365;

  /* Text Colors */
  --color-text-dark: #1A1A1A;
  --color-text-muted: #5F6B6B;

  /* Border and Background */
  --color-border-gray: #E3E7E5;
  --color-background: #FFFFFF;
  --color-background-secondary: #F8F9F7;

  /* Elevated Surfaces (cards, modals, popovers) */
  --color-bg-elevated: #FFFFFF;
  --color-bg-hover: #E9F1F1;
  --color-bg-active: rgba(14, 58, 58, 0.12);
  --color-bg-input: #FFFFFF;
  --color-bg-overlay: rgba(255, 255, 255, 0.8);

  /* Text Variants */
  --color-text-heading: #1A1A1A;
  --color-text-link: #0E3A3A;
  --color-text-on-primary: #F8F9F7;
  --color-text-inverse: #FFFFFF;

  /* Header */
  --color-header-bg: #0E3A3A;

  /* Button Hover/Active States */
  --color-btn-primary-hover: #05292B;
  --color-btn-primary-active: #031F22;
  --color-btn-danger-bg: #DC2626;
  --color-btn-danger-hover: #B91C1C;
  --color-btn-success-bg: #059669;
  --color-btn-success-hover: #047857;
  --color-btn-warning-bg: #D97706;
  --color-btn-warning-hover: #B45309;
  --color-btn-info-bg: #1E40AF;
  --color-btn-info-hover: #1D4ED8;

  /* Alert/Flash Backgrounds and Text */
  --color-alert-success-bg: rgba(16, 185, 129, 0.1);
  --color-alert-success-text: #065F46;
  --color-alert-error-bg: rgba(239, 68, 68, 0.1);
  --color-alert-error-text: #7F1D1D;
  --color-alert-warning-bg: rgba(245, 158, 11, 0.1);
  --color-alert-warning-text: #78350F;
  --color-alert-info-bg: rgba(59, 130, 246, 0.1);
  --color-alert-info-text: #1E3A8A;

  /* Status Colors */
  --color-success: #10B981;
  --color-warning: #F59E0B;
  --color-error: #EF4444;
  --color-info: #3B82F6;

  /* Priority Colors */
  --color-priority-low: #6B7280;
  --color-priority-medium: #3B82F6;
  --color-priority-high: #F97316;
  --color-priority-urgent: #DC2626;

  /* ============================================
     Typography
     ============================================ */

  /* Font Family */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;

  /* Font Sizes */
  --font-size-h1: 24px;
  --font-size-h2: 20px;
  --font-size-h3: 16px;
  --font-size-body: 14px;
  --font-size-small: 12px;

  /* Font Weights */
  --font-weight-regular: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;

  /* Line Heights */
  --line-height-tight: 1.2;
  --line-height-normal: 1.5;
  --line-height-loose: 1.75;

  /* ============================================
     Spacing (base unit: 4px)
     ============================================ */
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 8px;
  --spacing-lg: 16px;
  --spacing-xl: 24px;
  --spacing-xxl: 32px;

  /* ============================================
     Border Radius
     ============================================ */
  --radius-button: 6px;
  --radius-card: 8px;

  /* ============================================
     Shadows
     ============================================ */
  --shadow-card: 0 2px 4px rgba(0, 0, 0, 0.08);
  --shadow-card-hover: 0 4px 8px rgba(0, 0, 0, 0.12);
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);

  /* ============================================
     Focus Ring (Accessibility)
     ============================================ */
  --focus-ring: 2px solid var(--color-primary-dark);
  --focus-ring-color: var(--color-primary-dark);
  --focus-ring-width: 2px;
  --focus-ring-offset: 2px;

  /* ============================================
     Layout Dimensions
     ============================================ */
  --header-height: 56px;
  --sidebar-width: 240px;
  --sidebar-collapsed-width: 60px;
  --main-content-padding: var(--spacing-lg);

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

  /* ============================================
     Z-index Scales
     ============================================ */
  --z-dropdown: 1000;
  --z-sticky: 100;
  --z-fixed: 1020;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-popover: 1060;
  --z-tooltip: 1070;
}

/* High contrast mode support */
@media (prefers-contrast: more) {
  :root {
    --shadow-card: 0 2px 4px rgba(0, 0, 0, 0.16);
    --color-border-gray: #A1A9A7;
  }
}

/* Reduced motion support for accessibility */
@media (prefers-reduced-motion: reduce) {
  :root {
    --transition-fast: 0ms;
    --transition-base: 0ms;
    --transition-slow: 0ms;
  }
}