/* ==========================================================================
 * variables.css — CSS Custom Properties (Design Tokens)
 *
 * Single source of truth for all visual design tokens used across the app.
 * Components and pages reference these variables instead of hardcoded values.
 *
 * Design reference: design.md Section 2.4 Responsive Layout (lines 858-938)
 * ========================================================================== */

:root {
  /* ------------------------------------------------------------------
   * Breakpoints (for documentation; used in media queries)
   * Mobile:  < 768px
   * Tablet:  768px - 1024px
   * Desktop: > 1024px
   * ------------------------------------------------------------------ */
  --bp-mobile: 768px;
  --bp-tablet: 1024px;

  /* ------------------------------------------------------------------
   * Layout Dimensions
   * ------------------------------------------------------------------ */
  --sidebar-width: 240px;
  --header-height: 56px;
  --bottom-nav-height: 56px;

  /* ------------------------------------------------------------------
   * Colors — Status
   * Used for table status indicators and related badges.
   * ------------------------------------------------------------------ */
  --color-empty: #22c55e;            /* Green  — Ban trong */
  --color-serving: #f97316;          /* Orange — Dang phuc vu */
  --color-awaiting-payment: #ef4444; /* Red    — Cho thanh toan */
  --color-paid: #3b82f6;            /* Blue   — Da thanh toan */
  --color-reserved-pending: #a855f7; /* Purple — Dat truoc (cho den) */
  --color-reserved-active: #8b5cf6;  /* Violet — Dat truoc (da den) */

  /* ------------------------------------------------------------------
   * Colors — UI
   * ------------------------------------------------------------------ */
  --color-primary: #2563eb;
  --color-primary-hover: #1d4ed8;
  --color-danger: #dc2626;
  --color-success: #16a34a;
  --color-warning: #d97706;
  --color-info: #3b82f6;
  --color-bg: #f8fafc;
  --color-surface: #ffffff;
  --color-border: #e2e8f0;
  --color-text: #1e293b;
  --color-text-secondary: #64748b;
  --color-text-inverse: #ffffff;

  /* ------------------------------------------------------------------
   * Typography
   * Inter is the primary font, loaded from Google Fonts CDN.
   * System fonts serve as fallback for fast initial render.
   * ------------------------------------------------------------------ */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-size-xs: 0.75rem;    /* 12px */
  --font-size-sm: 0.875rem;   /* 14px */
  --font-size-base: 1rem;     /* 16px */
  --font-size-lg: 1.125rem;   /* 18px */
  --font-size-xl: 1.25rem;    /* 20px */
  --font-size-2xl: 1.5rem;    /* 24px */

  /* ------------------------------------------------------------------
   * Spacing
   * Based on a 4px (0.25rem) scale. Used for margin, padding, gap.
   * ------------------------------------------------------------------ */
  --space-1: 0.25rem;   /* 4px */
  --space-2: 0.5rem;    /* 8px */
  --space-3: 0.75rem;   /* 12px */
  --space-4: 1rem;      /* 16px */
  --space-6: 1.5rem;    /* 24px */
  --space-8: 2rem;      /* 32px */

  /* ------------------------------------------------------------------
   * Border Radius
   * ------------------------------------------------------------------ */
  --radius-sm: 0.25rem;   /* 4px  — subtle rounding */
  --radius-md: 0.5rem;    /* 8px  — cards, inputs */
  --radius-lg: 0.75rem;   /* 12px — modals, large cards */
  --radius-full: 9999px;  /* pill shape / circles */

  /* ------------------------------------------------------------------
   * 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);

  /* ------------------------------------------------------------------
   * Z-index Layers
   * Ordered from lowest to highest to prevent stacking conflicts.
   * ------------------------------------------------------------------ */
  --z-sidebar: 100;
  --z-header: 200;
  --z-modal-backdrop: 300;
  --z-modal: 400;
  --z-toast: 500;
  --z-tooltip: 600;

  /* ------------------------------------------------------------------
   * Transitions
   * ------------------------------------------------------------------ */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;

  /* ------------------------------------------------------------------
   * Currency
   * ------------------------------------------------------------------ */
  --currency-suffix: ' VND';

  /* ------------------------------------------------------------------
   * Enhancement Tokens
   * ------------------------------------------------------------------ */
  --color-focus-ring: rgba(37, 99, 235, 0.4);
  --color-primary-light: rgba(37, 99, 235, 0.1);
  --transition-page: 300ms ease;
  --backdrop-blur: 8px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #0f172a;
    --color-surface: #1e293b;
    --color-border: #334155;
    --color-text: #f1f5f9;
    --color-text-secondary: #94a3b8;
    --color-text-inverse: #0f172a;
    --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);
  }
}