/* ===========================================================
   CSS Variables (Design Tokens)
   =========================================================== */

:root {
  /* ===========================================================
     COLORS
     =========================================================== */
  
  /* Primary Colors */
  --color-primary: #18bc9c;
  --color-primary-dark: #128f76;
  --color-primary-light: #2ecc71;
  --color-header-bg: #00979c;
  
  /* Secondary Colors */
  --color-secondary: #2c3e50;
  --color-secondary-light: #34495e;
  --color-secondary-dark: #1a252f;
  
  /* Neutral Colors */
  --color-white: #ffffff;
  --color-black: #000000;
  --color-gray-100: #f8f9fa;
  --color-gray-200: #e9ecef;
  --color-gray-300: #dee2e6;
  --color-gray-400: #ced4da;
  --color-gray-500: #adb5bd;
  --color-gray-600: #6c757d;
  --color-gray-700: #495057;
  --color-gray-800: #343a40;
  --color-gray-900: #212529;
  
  /* Text Colors */
  --color-text-primary: #2c3e50;
  --color-text-secondary: #7f8c8d;
  --color-text-muted: #95a5a6;
  --color-text-light: #bdc3c7;
  
  /* Background Colors */
  --color-bg-primary: #ffffff;
  --color-bg-secondary: #f8f9fa;
  --color-bg-dark: #2c3e50;
  --color-bg-accent: #18bc9c;
  
  /* Status Colors */
  --color-success: #28a745;
  --color-warning: #ffc107;
  --color-danger: #dc3545;
  --color-info: #17a2b8;
  
  /* ===========================================================
     SPACING
     =========================================================== */
  
  --spacing-xs: 0.25rem;    /* 4px */
  --spacing-sm: 0.5rem;     /* 8px */
  --spacing-md: 1rem;       /* 16px */
  --spacing-lg: 1.5rem;     /* 24px */
  --spacing-xl: 2rem;       /* 32px */
  --spacing-2xl: 3rem;      /* 48px */
  --spacing-3xl: 4rem;      /* 64px */
  --spacing-4xl: 6rem;      /* 96px */
  
  /* ===========================================================
     TYPOGRAPHY
     =========================================================== */
  
  /* Font Families */
  --font-family-primary: "Lato", sans-serif;
  --font-family-heading: "Montserrat", sans-serif;
  --font-family-chinese: "Microsoft JhengHei", "Noto Sans TC", sans-serif;
  
  /* Font Sizes */
  --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 */
  --font-size-3xl: 1.875rem;  /* 30px */
  --font-size-4xl: 2.25rem;   /* 36px */
  --font-size-5xl: 3rem;      /* 48px */
  
  /* Font Weights */
  --font-weight-light: 300;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --font-weight-extrabold: 800;
  
  /* Line Heights */
  --line-height-tight: 1.25;
  --line-height-snug: 1.375;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.625;
  --line-height-loose: 2;
  
  /* Letter Spacing */
  --letter-spacing-tight: -0.025em;
  --letter-spacing-normal: 0;
  --letter-spacing-wide: 0.025em;
  --letter-spacing-wider: 0.05em;
  --letter-spacing-widest: 0.1em;
  
  /* ===========================================================
     LAYOUT
     =========================================================== */
  
  /* Container */
  --container-max-width: 1600px;
  --container-padding: var(--spacing-xl);
  
  /* Border Radius */
  --border-radius-sm: 0.25rem;   /* 4px */
  --border-radius-md: 0.5rem;     /* 8px */
  --border-radius-lg: 0.75rem;    /* 12px */
  --border-radius-xl: 1rem;       /* 16px */
  --border-radius-full: 9999px;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  
  /* ===========================================================
     TRANSITIONS
     =========================================================== */
  
  --transition-fast: 0.15s ease;
  --transition-normal: 0.3s ease;
  --transition-slow: 0.5s ease;
  
  /* ===========================================================
     BREAKPOINTS (for reference in CSS)
     =========================================================== */
  
  --breakpoint-sm: 575px;
  --breakpoint-md: 768px;
  --breakpoint-lg: 1000px;
  --breakpoint-xl: 1220px;
  --breakpoint-2xl: 1620px;
  
  /* ===========================================================
     Z-INDEX
     =========================================================== */
  
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-popover: 1060;
  --z-tooltip: 1070;
}