/* CSS Design System Variables */
:root {
  /* Enhanced Color System */
  /* Primary Colors - Modern Blue/Indigo Scale */
  --primary-50: #f0f5ff;
  --primary-100: #e0ecff;
  --primary-200: #c7ddff;
  --primary-300: #a5c8ff;
  --primary-400: #7ea6ff;
  --primary-500: #6366f1;
  --primary-600: #4f46e5;
  --primary-700: #4338ca;
  --primary-800: #3730a3;
  --primary-900: #312e81;
  --primary-950: #1e1b4b;
  
  /* Neutral Colors - Sophisticated Gray Scale */
  --neutral-0: #ffffff;
  --neutral-50: #fafafa;
  --neutral-100: #f5f5f5;
  --neutral-200: #e5e5e5;
  --neutral-300: #d4d4d4;
  --neutral-400: #a3a3a3;
  --neutral-500: #737373;
  --neutral-600: #525252;
  --neutral-700: #404040;
  --neutral-800: #262626;
  --neutral-900: #171717;
  --neutral-950: #0a0a0a;
  
  /* Semantic Colors */
  --success-50: #f0fdf4;
  --success-500: #22c55e;
  --success-600: #16a34a;
  --success-900: #14532d;
  
  --warning-50: #fffbeb;
  --warning-500: #f59e0b;
  --warning-600: #d97706;
  --warning-900: #92400e;
  
  --error-50: #fef2f2;
  --error-500: #ef4444;
  --error-600: #dc2626;
  --error-900: #7f1d1d;
  
  /* Theme Colors - Light Mode */
  --color-primary: var(--primary-600);
  --color-primary-hover: var(--primary-700);
  --color-primary-light: var(--primary-100);
  
  --color-text-primary: var(--neutral-900);
  --color-text-secondary: var(--neutral-600);
  --color-text-muted: var(--neutral-500);
  --color-text-light: var(--neutral-400);
  --color-text-inverse: var(--neutral-0);
  
  --color-bg-primary: var(--neutral-0);
  --color-bg-secondary: var(--neutral-50);
  --color-bg-tertiary: var(--neutral-100);
  --color-bg-hover: var(--neutral-50);
  --color-bg-active: var(--neutral-100);
  
  --color-border: var(--neutral-200);
  --color-border-light: var(--neutral-100);
  --color-border-strong: var(--neutral-300);
  --color-border-focus: var(--primary-500);
  
  /* Typography Scale */
  --font-family-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-family-mono: 'JetBrains Mono', 'Fira Code', Consolas, 'Monaco', monospace;
  
  /* Fluid Font Sizes using clamp() for responsive typography */
  --font-size-xs: clamp(0.7rem, 0.66rem + 0.2vw, 0.75rem);          /* 11px - 12px */
  --font-size-sm: clamp(0.8rem, 0.75rem + 0.25vw, 0.875rem);        /* 13px - 14px */
  --font-size-base: clamp(0.9rem, 0.85rem + 0.25vw, 1rem);          /* 14px - 16px */
  --font-size-lg: clamp(1rem, 0.95rem + 0.3vw, 1.125rem);           /* 16px - 18px */
  --font-size-xl: clamp(1.125rem, 1rem + 0.6vw, 1.333rem);          /* 18px - 21px */
  --font-size-2xl: clamp(1.333rem, 1.1rem + 1.15vw, 1.777rem);      /* 21px - 28px */
  --font-size-3xl: clamp(1.777rem, 1.4rem + 1.85vw, 2.369rem);      /* 28px - 38px */
  --font-size-4xl: clamp(2.369rem, 1.8rem + 2.8vw, 3.157rem);       /* 38px - 51px */
  --font-size-5xl: clamp(3.157rem, 2.4rem + 3.8vw, 4.209rem);       /* 51px - 67px */
  --font-size-6xl: clamp(4.209rem, 3rem + 6vw, 5.610rem);           /* 67px - 90px */
  
  /* Font Weights */
  --font-weight-light: 300;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  
  /* Responsive Line Heights */
  --line-height-tight: clamp(1.2, 1.15 + 0.25vw, 1.25);
  --line-height-normal: clamp(1.4, 1.35 + 0.25vw, 1.5);
  --line-height-relaxed: clamp(1.6, 1.55 + 0.5vw, 1.75);
  --line-height-loose: clamp(1.8, 1.7 + 0.5vw, 2.0);
  
  /* Spacing Scale (8px Grid System) */
  --space-0: 0;
  --space-1: 0.25rem;   /* 4px */
  --space-2: 0.5rem;    /* 8px */
  --space-3: 0.75rem;   /* 12px */
  --space-4: 1rem;      /* 16px */
  --space-5: 1.25rem;   /* 20px */
  --space-6: 1.5rem;    /* 24px */
  --space-8: 2rem;      /* 32px */
  --space-10: 2.5rem;   /* 40px */
  --space-12: 3rem;     /* 48px */
  --space-16: 4rem;     /* 64px */
  --space-20: 5rem;     /* 80px */
  --space-24: 6rem;     /* 96px */
  --space-32: 8rem;     /* 128px */
  
  /* Border Radius */
  --radius-none: 0;
  --radius-sm: 0.125rem;    /* 2px */
  --radius-base: 0.25rem;   /* 4px */
  --radius-md: 0.375rem;    /* 6px */
  --radius-lg: 0.5rem;      /* 8px */
  --radius-xl: 0.75rem;     /* 12px */
  --radius-2xl: 1rem;       /* 16px */
  --radius-3xl: 1.5rem;     /* 24px */
  --radius-full: 9999px;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-base: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
  --shadow-2xl: 0 25px 50px -12px rgb(0 0 0 / 0.25);
  --shadow-inner: inset 0 2px 4px 0 rgb(0 0 0 / 0.05);
  
  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-base: 0.2s ease;
  --transition-smooth: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-bounce: 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
  
  /* Z-Index Scale */
  --z-dropdown: 1000;
  --z-sticky: 1010;
  --z-fixed: 1020;
  --z-modal-backdrop: 1030;
  --z-modal: 1040;
  --z-popover: 1050;
  --z-tooltip: 1060;
  
  /* Breakpoints (for JavaScript usage) */
  --breakpoint-sm: 640px;
  --breakpoint-md: 768px;
  --breakpoint-lg: 1024px;
  --breakpoint-xl: 1280px;
  --breakpoint-2xl: 1536px;
  
  /* RTL/LTR Specific Variables with fluid typography */
  --rtl-spacing: clamp(0.1em, 0.05em + 0.5vw, 0.2em);
  --arabic-line-height: clamp(1.7, 1.6 + 0.5vw, 1.9);
  --persian-line-height: clamp(1.8, 1.7 + 0.5vw, 2.0);
  --chinese-line-height: clamp(1.6, 1.5 + 0.5vw, 1.8);
  --rtl-border-radius: var(--radius-lg);
  
  /* Language-specific font sizing */
  --arabic-font-scale: 1.1;
  --persian-font-scale: 1.1;
  --chinese-font-scale: 1.05;
  --cyrillic-font-scale: 1.0;
  
  /* Content Width Constraints */
  --container-sm: 640px;
  --container-md: 768px;
  --container-lg: 1024px;
  --container-xl: 1280px;
  --container-2xl: 1536px;
  
  /* Performance Optimizations */
  --gpu-acceleration: translateZ(0);
  --will-change-transform: transform;
  --will-change-opacity: opacity;
  --will-change-scroll: scroll-position;
}

/* Dark Mode Variables */
[data-theme="dark"] {
  --color-primary: var(--primary-400);
  --color-primary-hover: var(--primary-300);
  --color-primary-light: var(--primary-950);
  
  --color-text-primary: var(--neutral-100);
  --color-text-secondary: var(--neutral-300);
  --color-text-muted: var(--neutral-400);
  --color-text-light: var(--neutral-500);
  --color-text-inverse: var(--neutral-900);
  
  --color-bg-primary: var(--neutral-900);
  --color-bg-secondary: var(--neutral-800);
  --color-bg-tertiary: var(--neutral-700);
  --color-bg-hover: var(--neutral-800);
  --color-bg-active: var(--neutral-700);
  
  --color-border: var(--neutral-700);
  --color-border-light: var(--neutral-800);
  --color-border-strong: var(--neutral-600);
}

/* Reduced Motion Support */
@media (prefers-reduced-motion: reduce) {
  :root {
    --transition-fast: 0ms;
    --transition-base: 0ms;
    --transition-smooth: 0ms;
    --transition-bounce: 0ms;
  }
}

/* System Preference Dark Mode */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --color-primary: var(--primary-400);
    --color-primary-hover: var(--primary-300);
    --color-primary-light: var(--primary-950);
    
    --color-text-primary: var(--neutral-100);
    --color-text-secondary: var(--neutral-300);
    --color-text-muted: var(--neutral-400);
    --color-text-light: var(--neutral-500);
    --color-text-inverse: var(--neutral-900);
    
    --color-bg-primary: var(--neutral-900);
    --color-bg-secondary: var(--neutral-800);
    --color-bg-tertiary: var(--neutral-700);
    --color-bg-hover: var(--neutral-800);
    --color-bg-active: var(--neutral-700);
    
    --color-border: var(--neutral-700);
    --color-border-light: var(--neutral-600);
    --color-border-strong: var(--neutral-600);
  }
}

/* Enhanced Language-Specific Variables */
:root[lang="ar"],
:root[lang="fa"],
[dir="rtl"] {
  --text-direction: rtl;
  --text-align: right;
  --border-start: border-right;
  --border-end: border-left;
  --margin-start: margin-right;
  --margin-end: margin-left;
  --padding-start: padding-right;
  --padding-end: padding-left;
  --font-family-primary: 'Noto Sans Arabic', 'Noto Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --line-height-base: var(--arabic-line-height);
}

:root[lang="fa"] {
  --font-family-primary: 'Noto Sans Arabic', 'Vazir', 'Tahoma', sans-serif;
  --line-height-base: var(--persian-line-height);
}

:root[lang="zh"],
:root[lang="zh-CN"],
:root[lang="zh-TW"] {
  --font-family-primary: 'Noto Sans SC', 'PingFang SC', 'Hiragino Sans GB', 'Source Han Sans SC', 'Microsoft YaHei', sans-serif;
  --line-height-base: var(--chinese-line-height);
}

:root[lang="ru"] {
  --font-family-primary: 'Inter', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
  --line-height-base: var(--line-height-normal);
}

:root[lang="en"],
:root[lang="fr"],
:root[lang="de"],
[dir="ltr"] {
  --text-direction: ltr;
  --text-align: left;
  --border-start: border-left;
  --border-end: border-right;
  --margin-start: margin-left;
  --margin-end: margin-right;
  --padding-start: padding-left;
  --padding-end: padding-right;
  --line-height-base: var(--line-height-normal);
}

/* High Contrast Support */
@media (prefers-contrast: high) {
  :root {
    --color-border: var(--neutral-900);
    --color-border-strong: var(--neutral-900);
    --shadow-sm: 0 0 0 1px var(--neutral-900);
    --shadow-base: 0 0 0 1px var(--neutral-900);
    --shadow-md: 0 0 0 2px var(--neutral-900);
  }
}