/* Korean Quiz Website - Main CSS */
/* Global styles and CSS variables for consistent theming */

:root {
  /* Color Palette - Enhanced for accessibility */
  --primary-color: #4338ca; /* Improved contrast ratio */
  --primary-hover: #312e81;
  --secondary-color: #0891b2; /* Improved contrast */
  --accent-color: #d97706; /* Improved contrast */
  --success-color: #059669; /* Improved contrast */
  --error-color: #dc2626; /* Improved contrast */
  --warning-color: #d97706;
  
  /* Neutral Colors */
  --white: #ffffff;
  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-300: #d1d5db;
  --gray-400: #9ca3af;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-800: #1f2937;
  --gray-900: #111827;
  
  /* Typography */
  --font-family-korean: 'Noto Sans KR', 'Malgun Gothic', '맑은 고딕', 'Apple SD Gothic Neo', sans-serif;
  --font-family-emoji: 'Apple Color Emoji', 'Segoe UI Emoji', 'Noto Color Emoji', sans-serif;
  
  /* Font Sizes */
  --text-xs: 0.75rem;    /* 12px */
  --text-sm: 0.875rem;   /* 14px */
  --text-base: 1rem;     /* 16px */
  --text-lg: 1.125rem;   /* 18px */
  --text-xl: 1.25rem;    /* 20px */
  --text-2xl: 1.5rem;    /* 24px */
  --text-3xl: 1.875rem;  /* 30px */
  --text-4xl: 2.25rem;   /* 36px */
  --text-5xl: 3rem;      /* 48px */
  
  /* Font Weights */
  --font-light: 300;
  --font-normal: 400;
  --font-medium: 500;
  --font-semibold: 600;
  --font-bold: 700;
  
  /* Line Heights */
  --leading-tight: 1.25;
  --leading-normal: 1.5;
  --leading-relaxed: 1.625;
  
  /* Spacing */
  --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 */
  
  /* Border Radius */
  --radius-sm: 0.125rem;  /* 2px */
  --radius-md: 0.375rem;  /* 6px */
  --radius-lg: 0.5rem;    /* 8px */
  --radius-xl: 0.75rem;   /* 12px */
  --radius-2xl: 1rem;     /* 16px */
  --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: 150ms ease-in-out;
  --transition-normal: 300ms ease-in-out;
  --transition-slow: 500ms ease-in-out;
  
  /* Z-index */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal: 1040;
  --z-popover: 1050;
  --z-tooltip: 1060;
}

/* Reset and Base Styles */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  -ms-text-size-adjust: 100%;
}

body {
  font-family: var(--font-family-korean);
  font-size: var(--text-base);
  font-weight: var(--font-normal);
  line-height: var(--leading-normal);
  color: var(--gray-900);
  background-color: var(--white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

/* Korean Text Optimization */
body {
  word-break: keep-all;
  overflow-wrap: break-word;
  -webkit-hyphens: auto;
  -ms-hyphens: auto;
  hyphens: auto;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: var(--font-bold);
  line-height: var(--leading-tight);
  margin-bottom: var(--space-4);
  color: var(--gray-900);
}

h1 {
  font-size: var(--text-4xl);
}

h2 {
  font-size: var(--text-3xl);
}

h3 {
  font-size: var(--text-2xl);
}

h4 {
  font-size: var(--text-xl);
}

h5 {
  font-size: var(--text-lg);
}

h6 {
  font-size: var(--text-base);
}

p {
  margin-bottom: var(--space-4);
  line-height: var(--leading-relaxed);
}

/* Links */
a {
  color: var(--primary-color);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--primary-hover);
  text-decoration: underline;
}

a:focus {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

/* Lists */
ul, ol {
  margin-bottom: var(--space-4);
  padding-left: var(--space-6);
}

li {
  margin-bottom: var(--space-2);
}

/* Images */
img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* Layout Utilities */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-4);
}

.section {
  padding: var(--space-16) 0;
}

.text-center {
  text-align: center;
}

.text-left {
  text-align: left;
}

.text-right {
  text-align: right;
}

/* Flexbox Utilities */
.flex {
  display: flex;
}

.flex-col {
  flex-direction: column;
}

.flex-wrap {
  flex-wrap: wrap;
}

.items-center {
  align-items: center;
}

.items-start {
  align-items: flex-start;
}

.items-end {
  align-items: flex-end;
}

.justify-center {
  justify-content: center;
}

.justify-between {
  justify-content: space-between;
}

.justify-around {
  justify-content: space-around;
}

.justify-start {
  justify-content: flex-start;
}

.justify-end {
  justify-content: flex-end;
}

/* Grid Utilities */
.grid {
  display: grid;
}

.grid-cols-1 {
  grid-template-columns: repeat(1, minmax(0, 1fr));
}

.grid-cols-2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.grid-cols-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.gap-4 {
  gap: var(--space-4);
}

.gap-6 {
  gap: var(--space-6);
}

.gap-8 {
  gap: var(--space-8);
}

/* Spacing Utilities */
.mb-2 { margin-bottom: var(--space-2); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }
.mb-8 { margin-bottom: var(--space-8); }

.mt-2 { margin-top: var(--space-2); }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mt-8 { margin-top: var(--space-8); }

.p-2 { padding: var(--space-2); }
.p-4 { padding: var(--space-4); }
.p-6 { padding: var(--space-6); }
.p-8 { padding: var(--space-8); }

.px-4 { 
  padding-left: var(--space-4);
  padding-right: var(--space-4);
}

.py-2 {
  padding-top: var(--space-2);
  padding-bottom: var(--space-2);
}

.py-4 {
  padding-top: var(--space-4);
  padding-bottom: var(--space-4);
}

/* Visibility */
.hidden {
  display: none;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Focus Styles for Accessibility */
.focus-visible:focus {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

/* Smooth Animations */
* {
  transition: background-color var(--transition-fast), 
              border-color var(--transition-fast), 
              color var(--transition-fast), 
              fill var(--transition-fast), 
              stroke var(--transition-fast), 
              opacity var(--transition-fast), 
              box-shadow var(--transition-fast), 
              transform var(--transition-fast);
}

/* Accessibility Enhancements */

/* High contrast focus indicators */
*:focus {
  outline: 3px solid var(--primary-color);
  outline-offset: 2px;
}

/* Skip to main content link */
.skip-link {
  position: absolute;
  top: -40px;
  left: 6px;
  background: var(--primary-color);
  color: var(--white);
  padding: 8px;
  text-decoration: none;
  border-radius: 4px;
  z-index: 1000;
}

.skip-link:focus {
  top: 6px;
}

/* Screen reader only content */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Enhanced button focus for accessibility */
.btn:focus,
.option-btn:focus,
.quiz-start-btn:focus {
  outline: 3px solid var(--primary-color);
  outline-offset: 2px;
  box-shadow: 0 0 0 6px rgba(67, 56, 202, 0.2);
}

/* High contrast mode support */
@media (prefers-contrast: high) {
  :root {
    --primary-color: #000080;
    --primary-hover: #000060;
    --gray-700: #000000;
    --gray-600: #333333;
    --gray-500: #666666;
  }
  
  .btn,
  .option-btn,
  .quiz-card {
    border: 2px solid var(--gray-700);
  }
  
  .btn:hover,
  .option-btn:hover {
    border-color: var(--primary-color);
    border-width: 3px;
  }
}

/* Reduced motion preferences */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  
  .floating-emoji {
    animation: none;
  }
}

/* Enhanced color contrast for Korean text */
body {
  color: var(--gray-800); /* Improved contrast for Korean text */
}

h1, h2, h3, h4, h5, h6 {
  color: var(--gray-900); /* Maximum contrast for headings */
}

/* Improved link contrast */
a {
  color: var(--primary-color);
  text-decoration: underline;
}

a:hover {
  color: var(--primary-hover);
  text-decoration: underline;
}

/* Better contrast for form elements */
.form-input,
.form-select {
  border: 2px solid var(--gray-400);
  color: var(--gray-800);
}

.form-input:focus,
.form-select:focus {
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(67, 56, 202, 0.2);
}

/* Accessible error states */
.error {
  color: var(--error-color);
  font-weight: var(--font-medium);
}

.success {
  color: var(--success-color);
  font-weight: var(--font-medium);
}

/* Accessible loading states */
.loading {
  position: relative;
}

.loading::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 20px;
  height: 20px;
  margin: -10px 0 0 -10px;
  border: 2px solid var(--gray-300);
  border-top-color: var(--primary-color);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

/* Accessible tooltips */
[data-tooltip] {
  position: relative;
}

[data-tooltip]:hover::after {
  content: attr(data-tooltip);
  position: absolute;
  bottom: 100%;
  left: 50%;
  transform: translateX(-50%);
  background: var(--gray-800);
  color: var(--white);
  padding: 4px 8px;
  border-radius: 4px;
  font-size: var(--text-sm);
  white-space: nowrap;
  z-index: 1000;
}