/* ==========================================================================
   CSS Variables - Apple Human Interface Guidelines Inspired
   ========================================================================== */

:root {
  /* Colors - Primary Palette */
  --color-background: #F5F5F7;
  --color-surface: #FFFFFF;
  --color-surface-elevated: #FFFFFF;

  /* Text Colors */
  --color-text-primary: #1D1D1F;
  --color-text-secondary: #86868B;
  --color-text-tertiary: #AEAEB2;
  --color-text-inverse: #FFFFFF;

  /* Brand/Accent Colors - Apple System Colors */
  --color-blue: #007AFF;
  --color-blue-hover: #0056CC;
  --color-green: #34C759;
  --color-green-light: #E8F8EC;
  --color-red: #FF3B30;
  --color-red-light: #FFEBE9;
  --color-orange: #FF9500;
  --color-orange-light: #FFF4E5;
  --color-purple: #AF52DE;
  --color-purple-light: #F5EAFA;
  --color-teal: #5AC8FA;
  --color-teal-light: #E5F6FD;
  --color-pink: #FF2D55;
  --color-yellow: #FFCC00;
  --color-indigo: #5856D6;

  /* Chart Colors */
  --chart-blue: #007AFF;
  --chart-green: #34C759;
  --chart-orange: #FF9500;
  --chart-purple: #AF52DE;
  --chart-teal: #5AC8FA;
  --chart-red: #FF3B30;

  /* Semantic Colors */
  --color-success: var(--color-green);
  --color-success-bg: var(--color-green-light);
  --color-error: var(--color-red);
  --color-error-bg: var(--color-red-light);
  --color-warning: var(--color-orange);
  --color-warning-bg: var(--color-orange-light);
  --color-info: var(--color-blue);
  --color-info-bg: #E5F1FF;

  /* Border Colors */
  --color-border: #E5E5EA;
  --color-border-light: #F2F2F7;
  --color-border-hover: #D1D1D6;
  --color-border-focus: var(--color-blue);

  /* Typography - Apple System Fonts */
  --font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Helvetica Neue", "Segoe UI", Roboto, sans-serif;
  --font-family-mono: "SF Mono", SFMono-Regular, ui-monospace, Menlo, Monaco, monospace;

  /* Font Sizes */
  --font-size-xs: 12px;
  --font-size-sm: 14px;
  --font-size-base: 16px;
  --font-size-lg: 18px;
  --font-size-xl: 20px;
  --font-size-2xl: 24px;
  --font-size-3xl: 28px;
  --font-size-4xl: 32px;
  --font-size-5xl: 40px;
  --font-size-6xl: 48px;

  /* Font Weights */
  --font-weight-light: 300;
  --font-weight-regular: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  /* Line Heights */
  --line-height-tight: 1.2;
  --line-height-base: 1.5;
  --line-height-relaxed: 1.75;

  /* Spacing - 8px Grid System */
  --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;
  --space-16: 64px;
  --space-20: 80px;
  --space-24: 96px;

  /* Border Radius */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-2xl: 20px;
  --radius-full: 9999px;

  /* Shadows - Subtle, Apple-style */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 2px 8px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.08);
  --shadow-xl: 0 8px 32px rgba(0, 0, 0, 0.1);
  --shadow-card: 0 2px 8px rgba(0, 0, 0, 0.06);
  --shadow-card-hover: 0 4px 16px rgba(0, 0, 0, 0.1);
  --shadow-dropdown: 0 4px 24px rgba(0, 0, 0, 0.12);

  /* Transitions */
  --transition-fast: 150ms ease-out;
  --transition-base: 200ms ease-out;
  --transition-slow: 300ms ease-out;
  --transition-slower: 400ms ease-out;

  /* Z-Index Scale */
  --z-dropdown: 100;
  --z-sticky: 200;
  --z-modal-backdrop: 300;
  --z-modal: 400;
  --z-tooltip: 500;

  /* Layout */
  --sidebar-width: 260px;
  --sidebar-collapsed-width: 72px;
  --header-height: 64px;
  --content-max-width: 1400px;
}

/* Dark mode support (optional, for future) */
@media (prefers-color-scheme: dark) {
  :root {
    /* Can be enabled later */
  }
}