/* ============================================
   Bible Quiz AI - Modern Design System
   UI Designer: Professional Design Token System
   ============================================ */

/* ==========================================
   DESIGN TOKENS - Foundation Layer
   ========================================== */

:root {
  /* ===== Color Tokens - Primary Palette ===== */
  /* Main brand colors with biblical inspiration */
  --color-primary-50: #f0f4ff;
  --color-primary-100: #e0e9ff;
  --color-primary-200: #c7d7fe;
  --color-primary-300: #a5b8fc;
  --color-primary-400: #8996f8;
  --color-primary-500: #667eea;    /* Primary brand */
  --color-primary-600: #5568d3;
  --color-primary-700: #4553b8;
  --color-primary-800: #3a4495;
  --color-primary-900: #2d3670;

  /* ===== Secondary Palette - Biblical Purple ===== */
  --color-secondary-50: #faf5ff;
  --color-secondary-100: #f3e8ff;
  --color-secondary-200: #e9d5ff;
  --color-secondary-300: #d8b4fe;
  --color-secondary-400: #c084fc;
  --color-secondary-500: #a855f7;
  --color-secondary-600: #9333ea;
  --color-secondary-700: #7e22ce;
  --color-secondary-800: #6b21a8;
  --color-secondary-900: #581c87;

  /* ===== Semantic Colors ===== */
  --color-success-light: #d1fae5;
  --color-success: #10b981;
  --color-success-dark: #059669;

  --color-warning-light: #fef3c7;
  --color-warning: #f59e0b;
  --color-warning-dark: #d97706;

  --color-error-light: #fee2e2;
  --color-error: #ef4444;
  --color-error-dark: #dc2626;

  --color-info-light: #dbeafe;
  --color-info: #3b82f6;
  --color-info-dark: #2563eb;

  /* ===== Neutral Palette ===== */
  --color-gray-50: #f9fafb;
  --color-gray-100: #f3f4f6;
  --color-gray-200: #e5e7eb;
  --color-gray-300: #d1d5db;
  --color-gray-400: #9ca3af;
  --color-gray-500: #6b7280;
  --color-gray-600: #4b5563;
  --color-gray-700: #374151;
  --color-gray-800: #1f2937;
  --color-gray-900: #111827;

  /* ===== Difficulty Colors ===== */
  --difficulty-easy: #10b981;
  --difficulty-easy-bg: #d1fae5;
  --difficulty-medium: #f59e0b;
  --difficulty-medium-bg: #fef3c7;
  --difficulty-hard: #ef4444;
  --difficulty-hard-bg: #fee2e2;

  /* ===== Typography Tokens ===== */
  --font-family-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  --font-family-display: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  --font-family-mono: 'JetBrains Mono', 'SF Mono', Consolas, monospace;

  /* Font Sizes - Modular Scale (1.25 ratio) */
  --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-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  /* Line Heights */
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;

  /* ===== Spacing Tokens - 4px base unit ===== */
  --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 */

  /* ===== Border Radius Tokens ===== */
  --radius-sm: 0.25rem;    /* 4px */
  --radius-md: 0.5rem;     /* 8px */
  --radius-lg: 0.75rem;    /* 12px */
  --radius-xl: 1rem;       /* 16px */
  --radius-2xl: 1.5rem;    /* 24px */
  --radius-full: 9999px;

  /* ===== Shadow Tokens ===== */
  --shadow-xs: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-sm: 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);

  /* ===== Transition Tokens ===== */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 200ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slower: 500ms cubic-bezier(0.4, 0, 0.2, 1);

  /* ===== Z-Index Scale ===== */
  --z-base: 0;
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-popover: 1060;
  --z-tooltip: 1070;
}

/* ==========================================
   GLOBAL RESET & BASE STYLES
   ========================================== */

*, *::before, *::after {
  box-sizing: border-box;
}

html {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

body {
  font-family: var(--font-family-primary);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-normal);
  color: var(--color-gray-900);
  background-color: var(--color-gray-50);
  margin: 0;
  padding: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ==========================================
   TYPOGRAPHY SYSTEM
   ========================================== */

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-family-display);
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
  color: var(--color-gray-900);
  margin-top: 0;
  margin-bottom: var(--space-4);
}

h1 { font-size: var(--font-size-4xl); }
h2 { font-size: var(--font-size-3xl); }
h3 { font-size: var(--font-size-2xl); }
h4 { font-size: var(--font-size-xl); }
h5 { font-size: var(--font-size-lg); }
h6 { font-size: var(--font-size-base); }

p {
  margin-top: 0;
  margin-bottom: var(--space-4);
  color: var(--color-gray-700);
}

a {
  color: var(--color-primary-600);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-primary-700);
  text-decoration: underline;
}

/* ==========================================
   BUTTON COMPONENT SYSTEM
   ========================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  font-family: var(--font-family-primary);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  line-height: 1;
  text-align: center;
  text-decoration: none;
  white-space: nowrap;
  border: 2px solid transparent;
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: all var(--transition-base);
  user-select: none;
  outline: none;
}

.btn:focus-visible {
  outline: 2px solid var(--color-primary-500);
  outline-offset: 2px;
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  pointer-events: none;
}

/* Button Variants */
.btn-primary {
  background: linear-gradient(135deg, var(--color-primary-500) 0%, var(--color-primary-600) 100%);
  color: white;
  border-color: var(--color-primary-600);
  box-shadow: var(--shadow-sm);
}

.btn-primary:hover:not(:disabled) {
  background: linear-gradient(135deg, var(--color-primary-600) 0%, var(--color-primary-700) 100%);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
  text-decoration: none;
}

.btn-secondary {
  background: var(--color-gray-100);
  color: var(--color-gray-900);
  border-color: var(--color-gray-300);
}

.btn-secondary:hover:not(:disabled) {
  background: var(--color-gray-200);
  border-color: var(--color-gray-400);
  transform: translateY(-1px);
  text-decoration: none;
}

.btn-success {
  background: var(--color-success);
  color: white;
  border-color: var(--color-success-dark);
}

.btn-success:hover:not(:disabled) {
  background: var(--color-success-dark);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
  text-decoration: none;
}

.btn-outline-primary {
  background: transparent;
  color: var(--color-primary-600);
  border-color: var(--color-primary-500);
}

.btn-outline-primary:hover:not(:disabled) {
  background: var(--color-primary-50);
  border-color: var(--color-primary-600);
  color: var(--color-primary-700);
  text-decoration: none;
}

/* Button Sizes */
.btn-sm {
  padding: var(--space-2) var(--space-4);
  font-size: var(--font-size-sm);
}

.btn-lg {
  padding: var(--space-4) var(--space-8);
  font-size: var(--font-size-lg);
}

.btn-block {
  display: flex;
  width: 100%;
}

/* ==========================================
   FORM COMPONENTS
   ========================================== */

.form-group {
  margin-bottom: var(--space-6);
}

.form-label {
  display: block;
  margin-bottom: var(--space-2);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-gray-700);
}

.form-input,
.form-select,
.form-textarea {
  width: 100%;
  padding: var(--space-3);
  font-family: var(--font-family-primary);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  color: var(--color-gray-900);
  background-color: white;
  border: 2px solid var(--color-gray-300);
  border-radius: var(--radius-md);
  transition: all var(--transition-base);
  outline: none;
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
  border-color: var(--color-primary-500);
  box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.form-input:disabled,
.form-select:disabled,
.form-textarea:disabled {
  background-color: var(--color-gray-100);
  cursor: not-allowed;
  opacity: 0.6;
}

.form-textarea {
  resize: vertical;
  min-height: 120px;
}

/* Radio Button Custom Styling */
.form-radio-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.form-radio-label {
  display: flex;
  align-items: center;
  padding: var(--space-4);
  background: white;
  border: 2px solid var(--color-gray-300);
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: all var(--transition-base);
}

.form-radio-label:hover {
  background: var(--color-gray-50);
  border-color: var(--color-primary-400);
}

.form-radio-label input[type="radio"] {
  margin-right: var(--space-3);
  width: 20px;
  height: 20px;
  accent-color: var(--color-primary-500);
  cursor: pointer;
}

.form-radio-label input[type="radio"]:checked + .radio-text {
  font-weight: var(--font-weight-semibold);
  color: var(--color-primary-700);
}

.form-radio-label:has(input:checked) {
  background: var(--color-primary-50);
  border-color: var(--color-primary-500);
}

/* ==========================================
   CARD COMPONENT SYSTEM
   ========================================== */

.card {
  background: white;
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  transition: all var(--transition-base);
}

.card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.card-header {
  padding: var(--space-6);
  border-bottom: 1px solid var(--color-gray-200);
  background: var(--color-gray-50);
}

.card-body {
  padding: var(--space-6);
}

.card-footer {
  padding: var(--space-6);
  border-top: 1px solid var(--color-gray-200);
  background: var(--color-gray-50);
}

.card-title {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  color: var(--color-gray-900);
  margin-bottom: var(--space-2);
}

/* ==========================================
   BADGE COMPONENTS
   ========================================== */

.badge {
  display: inline-flex;
  align-items: center;
  padding: var(--space-1) var(--space-3);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  line-height: 1;
  border-radius: var(--radius-full);
  white-space: nowrap;
}

.badge-primary {
  background: var(--color-primary-100);
  color: var(--color-primary-700);
}

.badge-success {
  background: var(--color-success-light);
  color: var(--color-success-dark);
}

.badge-warning {
  background: var(--color-warning-light);
  color: var(--color-warning-dark);
}

.badge-error {
  background: var(--color-error-light);
  color: var(--color-error-dark);
}

/* Difficulty Badges */
.badge-easy {
  background: var(--difficulty-easy-bg);
  color: var(--difficulty-easy);
  font-weight: var(--font-weight-semibold);
}

.badge-medium {
  background: var(--difficulty-medium-bg);
  color: var(--difficulty-medium);
  font-weight: var(--font-weight-semibold);
}

.badge-hard {
  background: var(--difficulty-hard-bg);
  color: var(--difficulty-hard);
  font-weight: var(--font-weight-semibold);
}

/* ==========================================
   ALERT COMPONENTS
   ========================================== */

.alert {
  padding: var(--space-4);
  border-radius: var(--radius-lg);
  border-left: 4px solid;
  margin-bottom: var(--space-4);
}

.alert-success {
  background: var(--color-success-light);
  border-color: var(--color-success);
  color: var(--color-success-dark);
}

.alert-warning {
  background: var(--color-warning-light);
  border-color: var(--color-warning);
  color: var(--color-warning-dark);
}

.alert-error,
.alert-danger {
  background: var(--color-error-light);
  border-color: var(--color-error);
  color: var(--color-error-dark);
}

.alert-info {
  background: var(--color-info-light);
  border-color: var(--color-info);
  color: var(--color-info-dark);
}

/* ==========================================
   PROGRESS BAR COMPONENT
   ========================================== */

.progress-container {
  width: 100%;
  height: 8px;
  background: var(--color-gray-200);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  background: linear-gradient(90deg, var(--color-primary-500) 0%, var(--color-secondary-500) 100%);
  border-radius: var(--radius-full);
  transition: width var(--transition-slow);
}

/* ==========================================
   NAVIGATION COMPONENTS
   ========================================== */

.navbar {
  background: linear-gradient(135deg, var(--color-primary-700) 0%, var(--color-primary-800) 100%);
  box-shadow: var(--shadow-md);
  padding: var(--space-4) 0;
}

.navbar-brand {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  color: white !important;
  text-decoration: none;
  transition: opacity var(--transition-fast);
}

.navbar-brand:hover {
  opacity: 0.9;
  text-decoration: none;
}

.nav-link {
  color: rgba(255, 255, 255, 0.85) !important;
  font-weight: var(--font-weight-medium);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.nav-link:hover {
  color: white !important;
  background: rgba(255, 255, 255, 0.1);
  text-decoration: none;
}

/* ==========================================
   UTILITY CLASSES
   ========================================== */

/* Spacing Utilities */
.mt-0 { margin-top: 0; }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mt-8 { margin-top: var(--space-8); }

.mb-0 { margin-bottom: 0; }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }
.mb-8 { margin-bottom: var(--space-8); }

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

/* Text Utilities */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.text-primary { color: var(--color-primary-600); }
.text-success { color: var(--color-success); }
.text-warning { color: var(--color-warning); }
.text-error { color: var(--color-error); }
.text-muted { color: var(--color-gray-500); }

.font-bold { font-weight: var(--font-weight-bold); }
.font-semibold { font-weight: var(--font-weight-semibold); }
.font-medium { font-weight: var(--font-weight-medium); }

/* Display Utilities */
.d-flex { display: flex; }
.d-block { display: block; }
.d-inline-block { display: inline-block; }
.d-none { display: none; }

/* ==========================================
   RESPONSIVE DESIGN - Mobile First
   ========================================== */

/* Tablet devices (640px and up) */
@media (min-width: 640px) {
  h1 { font-size: var(--font-size-5xl); }
  h2 { font-size: var(--font-size-4xl); }

  .container {
    max-width: 640px;
  }
}

/* Desktop devices (768px and up) */
@media (min-width: 768px) {
  .container {
    max-width: 768px;
  }
}

/* Large desktop devices (1024px and up) */
@media (min-width: 1024px) {
  .container {
    max-width: 1024px;
    padding-left: var(--space-8);
    padding-right: var(--space-8);
  }
}

/* Extra large devices (1280px and up) */
@media (min-width: 1280px) {
  .container {
    max-width: 1280px;
  }
}

/* ==========================================
   ACCESSIBILITY ENHANCEMENTS
   ========================================== */

/* Focus visible for keyboard navigation */
*:focus-visible {
  outline: 2px solid var(--color-primary-500);
  outline-offset: 2px;
}

/* 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;
  }
}

/* High contrast mode support */
@media (prefers-contrast: high) {
  .btn {
    border-width: 2px;
  }

  .card {
    border-width: 2px;
  }
}