/**
 * Naturalize V2 - Modern Mobile-First Styles
 * Version: 2.0.0
 * Date: November 10, 2025
 */

/* ========================================
   ROOT VARIABLES & THEME COLORS
   ======================================== */
:root {
  /* Light Theme Colors */
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-tertiary: #f1f5f9;
  --text-primary: #1a1a1a;
  --text-secondary: #64748b;
  --text-muted: #94a3b8;
  
  /* Brand Colors (USCIS Theme) */
  --color-primary: #0b3d91;
  --color-primary-hover: #0a3577;
  --color-secondary: #dc143c;
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --color-danger: #ef4444;
  --color-info: #3b82f6;
  
  /* UI Elements */
  --border-color: #e2e8f0;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  
  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 
                 'Noto Sans', sans-serif;
  --font-size-base: 18px;
  --font-size-sm: 16px;
  --font-size-lg: 20px;
  --font-size-xl: 24px;
  --line-height: 1.6;
  
  /* Spacing (8px base unit) */
  --space-xs: 0.5rem;   /* 8px */
  --space-sm: 1rem;     /* 16px */
  --space-md: 1.5rem;   /* 24px */
  --space-lg: 2rem;     /* 32px */
  --space-xl: 3rem;     /* 48px */
  
  /* Transitions */
  --transition-fast: 0.15s ease-out;
  --transition-normal: 0.3s ease-out;
  --transition-slow: 0.5s ease-out;
}

/* Dark Theme */
[data-theme="dark"] {
  --bg-primary: #1a1a1a;
  --bg-secondary: #2d2d2d;
  --bg-tertiary: #404040;
  --text-primary: #ffffff;
  --text-secondary: #e0e0e0;
  --text-muted: #b0b0b0;
  --border-color: #505050;
  --color-primary: #4a9eff;
  --color-primary-hover: #6bb2ff;
  --color-success: #4ade80;
  --color-warning: #fbbf24;
  --color-danger: #f87171;
  --color-info: #60a5fa;
  
  /* Better shadow for dark mode */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5);
}

/* High Contrast Mode */
[data-theme="high-contrast"] {
  --bg-primary: #000000;
  --bg-secondary: #1a1a1a;
  --text-primary: #ffffff;
  --text-secondary: #e5e5e5;
  --color-primary: #ffff00;
  --color-primary-hover: #ffff66;
  --border-color: #ffffff;
}

/* ========================================
   BASE STYLES
   ======================================== */
* {
  box-sizing: border-box;
}

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: var(--line-height);
  color: var(--text-primary);
  background-color: var(--bg-primary);
  transition: background-color var(--transition-normal),
              color var(--transition-normal);
  margin: 0;
  padding: 0;
}

/* ========================================
   MOBILE-FIRST TYPOGRAPHY
   ======================================== */
h1, h2, h3, h4, h5, h6 {
  margin-top: 0;
  margin-bottom: var(--space-sm);
  font-weight: 600;
  line-height: 1.2;
  color: var(--text-primary);
}

h1 { font-size: clamp(28px, 6vw, 36px); }
h2 { font-size: clamp(24px, 5vw, 30px); }
h3 { font-size: clamp(20px, 4vw, 24px); }
h4 { font-size: clamp(18px, 3.5vw, 20px); }

p {
  margin-top: 0;
  margin-bottom: var(--space-sm);
}

.text-muted {
  color: var(--text-muted) !important;
}

.text-secondary {
  color: var(--text-secondary) !important;
}

/* ========================================
   TOUCH-OPTIMIZED BUTTONS
   ======================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  min-width: 48px;
  padding: 12px 24px;
  font-size: 18px;
  font-weight: 500;
  line-height: 1.5;
  text-align: center;
  text-decoration: none;
  border: 2px solid transparent;
  border-radius: 8px;
  cursor: pointer;
  transition: all var(--transition-fast);
  -webkit-tap-highlight-color: transparent;
  user-select: none;
}

.btn:active {
  transform: scale(0.96);
}

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

.btn-primary:hover,
.btn-primary:focus {
  background-color: var(--color-primary-hover);
  border-color: var(--color-primary-hover);
  color: white;
  text-decoration: none;
}

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

.btn-success:hover {
  background-color: var(--color-success);
  border-color: var(--color-success);
  filter: brightness(0.9);
  color: white;
}

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

.btn-danger:hover {
  background-color: var(--color-danger);
  border-color: var(--color-danger);
  filter: brightness(0.9);
  color: white;
}

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

.btn-outline-primary:hover {
  background-color: var(--color-primary);
  color: white;
}

.btn-lg {
  min-height: 56px;
  padding: 16px 32px;
  font-size: 20px;
}

.btn-sm {
  min-height: 40px;
  padding: 8px 16px;
  font-size: 16px;
}

/* ========================================
   CARDS & CONTAINERS
   ======================================== */
.card {
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 0;
  margin-bottom: var(--space-md);
  box-shadow: var(--shadow-md);
  transition: all var(--transition-normal);
  overflow: hidden;
}

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

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

.card-header {
  background: linear-gradient(135deg, var(--color-primary), var(--color-info));
  color: white;
  padding: var(--space-md) var(--space-lg);
  border-bottom: none;
  border-radius: 0;
}

.card-title {
  font-size: var(--font-size-xl);
  font-weight: 700;
  margin-bottom: var(--space-sm);
  color: var(--text-primary);
  line-height: 1.3;
}

.card-text {
  color: var(--text-secondary);
  margin-bottom: var(--space-md);
  font-size: var(--font-size-base);
  line-height: 1.6;
}

.card-subtitle {
  color: var(--text-muted);
  font-size: var(--font-size-sm);
  font-weight: 500;
  margin-bottom: var(--space-sm);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* Feature cards for homepage */
.feature-card {
  border: none;
  background: linear-gradient(135deg, 
    rgba(255, 255, 255, 0.95), 
    rgba(255, 255, 255, 0.8));
  backdrop-filter: blur(10px);
  border-radius: 20px;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] .feature-card {
  background: linear-gradient(135deg, 
    rgba(45, 45, 45, 0.95), 
    rgba(45, 45, 45, 0.8));
}

.feature-card:hover {
  transform: translateY(-8px) scale(1.02);
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

.feature-icon {
  width: 60px;
  height: 60px;
  border-radius: 16px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-info));
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 28px;
  margin-bottom: var(--space-md);
}

/* Stats cards */
.stats-card {
  background: linear-gradient(135deg, var(--color-primary), var(--color-info));
  color: white;
  border: none;
  position: relative;
  overflow: hidden;
}

.stats-card::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle, rgba(255,255,255,0.1) 0%, transparent 70%);
  animation: shimmer 3s infinite linear;
}

@keyframes shimmer {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

.stats-number {
  font-size: clamp(2rem, 8vw, 4rem);
  font-weight: 800;
  line-height: 0.9;
  margin-bottom: var(--space-xs);
  text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

.stats-label {
  font-size: var(--font-size-sm);
  opacity: 0.95;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1px;
}

/* ========================================
   THEME SWITCHER
   ======================================== */
.theme-switcher {
  position: fixed;
  top: 20px;
  right: 20px;
  z-index: 1000;
}

.theme-toggle {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background-color: var(--bg-secondary);
  border: 2px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
  box-shadow: var(--shadow-md);
}

.theme-toggle:hover {
  transform: scale(1.05);
  box-shadow: var(--shadow-lg);
}

.theme-toggle svg {
  width: 24px;
  height: 24px;
  fill: var(--text-primary);
}

/* ========================================
   PROGRESS INDICATORS
   ======================================== */
.progress-bar-container {
  width: 100%;
  height: 8px;
  background-color: var(--bg-tertiary);
  border-radius: 4px;
  overflow: hidden;
  margin: var(--space-sm) 0;
}

.progress-bar {
  height: 100%;
  background: linear-gradient(90deg, var(--color-primary), var(--color-info));
  border-radius: 4px;
  transition: width var(--transition-slow);
}

.stat-card {
  background: linear-gradient(135deg, var(--color-primary), var(--color-info));
  color: white;
  border-radius: 12px;
  padding: var(--space-md);
  text-align: center;
  box-shadow: var(--shadow-md);
}

.stat-number {
  font-size: clamp(32px, 8vw, 48px);
  font-weight: 700;
  line-height: 1;
  margin-bottom: var(--space-xs);
}

.stat-label {
  font-size: var(--font-size-sm);
  opacity: 0.9;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* ========================================
   QUESTION CARD (Learning Mode)
   ======================================== */
.question-card {
  max-width: 900px;
  margin: var(--space-lg) auto;
  padding: var(--space-lg);
  background-color: var(--bg-primary);
  border-radius: 16px;
  box-shadow: var(--shadow-lg);
  animation: slideInUp 0.3s ease-out;
}

@keyframes slideInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.question-text {
  font-size: clamp(20px, 4vw, 24px);
  font-weight: 500;
  line-height: 1.4;
  margin: var(--space-md) 0;
  color: var(--text-primary);
}

.answer-area {
  background-color: var(--bg-secondary);
  border-left: 4px solid var(--color-success);
  padding: var(--space-md);
  border-radius: 8px;
  margin-top: var(--space-md);
}

/* ========================================
   AUDIO CONTROLS
   ======================================== */
.audio-btn {
  min-width: 48px;
  height: 48px;
  border-radius: 50%;
  background-color: var(--color-info);
  color: white;
  border: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
  box-shadow: var(--shadow-sm);
}

.audio-btn:hover {
  background-color: var(--color-info);
  filter: brightness(0.9);
  transform: scale(1.05);
  box-shadow: var(--shadow-md);
}

.audio-btn:active {
  transform: scale(0.95);
}

.audio-btn svg {
  width: 24px;
  height: 24px;
}

/* ========================================
   RESPONSIVE UTILITIES
   ======================================== */
.container-fluid {
  width: 100%;
  padding-right: var(--space-sm);
  padding-left: var(--space-sm);
  margin-right: auto;
  margin-left: auto;
}

.container {
  max-width: 1200px;
  padding-right: var(--space-sm);
  padding-left: var(--space-sm);
  margin-right: auto;
  margin-left: auto;
}

/* Mobile spacing */
@media (max-width: 768px) {
  .py-5 {
    padding-top: var(--space-md) !important;
    padding-bottom: var(--space-md) !important;
  }
  
  .mb-3 {
    margin-bottom: var(--space-sm) !important;
  }
}

/* Tablet and up */
@media (min-width: 768px) {
  .container {
    padding-right: var(--space-md);
    padding-left: var(--space-md);
  }
}

/* Desktop */
@media (min-width: 1024px) {
  .container {
    padding-right: var(--space-lg);
    padding-left: var(--space-lg);
  }
}

/* ========================================
   GRID SYSTEM (Mobile-First)
   ======================================== */
.row {
  display: flex;
  flex-wrap: wrap;
  margin-right: calc(var(--space-sm) * -0.5);
  margin-left: calc(var(--space-sm) * -0.5);
}

.col, .col-12, .col-md-6, .col-lg-4 {
  position: relative;
  width: 100%;
  padding-right: calc(var(--space-sm) * 0.5);
  padding-left: calc(var(--space-sm) * 0.5);
}

.col-12 { flex: 0 0 100%; max-width: 100%; }

@media (min-width: 768px) {
  .col-md-6 { flex: 0 0 50%; max-width: 50%; }
}

@media (min-width: 1024px) {
  .col-lg-4 { flex: 0 0 33.333333%; max-width: 33.333333%; }
}

/* ========================================
   ANIMATIONS & MICRO-INTERACTIONS
   ======================================== */
.fade-in {
  animation: fadeIn 0.3s ease-out;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

.slide-in {
  animation: slideIn 0.4s ease-out;
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateX(-20px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

/* Loading Spinner */
.spinner {
  display: inline-block;
  width: 40px;
  height: 40px;
  border: 4px solid var(--border-color);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

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

/* Focus states */
*:focus {
  outline: 3px solid var(--color-info);
  outline-offset: 2px;
}

*:focus:not(:focus-visible) {
  outline: none;
}

*:focus-visible {
  outline: 3px solid var(--color-info);
  outline-offset: 2px;
}

/* Skip to main content */
.skip-to-main {
  position: absolute;
  left: -9999px;
  z-index: 999;
  padding: var(--space-sm);
  background-color: var(--color-primary);
  color: white;
  text-decoration: none;
}

.skip-to-main:focus {
  left: 50%;
  transform: translateX(-50%);
  top: var(--space-sm);
}

/* ========================================
   ALERTS & FEEDBACK
   ======================================== */
.alert {
  padding: var(--space-md);
  border-radius: 8px;
  margin-bottom: var(--space-md);
  border-left: 4px solid;
}

.alert-success {
  background-color: #d1fae5;
  border-left-color: var(--color-success);
  color: #065f46;
}

.alert-info {
  background-color: #dbeafe;
  border-left-color: var(--color-info);
  color: #1e3a8a;
}

.alert-warning {
  background-color: #fef3c7;
  border-left-color: var(--color-warning);
  color: #92400e;
}

.alert-danger {
  background-color: #fee2e2;
  border-left-color: var(--color-danger);
  color: #991b1b;
}

[data-theme="dark"] .alert-success {
  background-color: #1b5e20;
  color: #c8e6c9;
  border-left-color: #4ade80;
}

[data-theme="dark"] .alert-info {
  background-color: #0d47a1;
  color: #bbdefb;
  border-left-color: #60a5fa;
}

[data-theme="dark"] .alert-warning {
  background-color: #e65100;
  color: #ffcc80;
  border-left-color: #fbbf24;
}

[data-theme="dark"] .alert-danger {
  background-color: #c62828;
  color: #ffcdd2;
  border-left-color: #f87171;
}

/* ========================================
   BADGES
   ======================================== */
.badge {
  display: inline-block;
  padding: 4px 12px;
  font-size: 14px;
  font-weight: 600;
  line-height: 1;
  border-radius: 16px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

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

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

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

/* ========================================
   UTILITIES
   ======================================== */
.text-center { text-align: center; }
.text-right { text-align: right; }
.text-left { text-align: left; }

.d-none { display: none !important; }
.d-block { display: block !important; }
.d-flex { display: flex !important; }
.d-inline-flex { display: inline-flex !important; }

.justify-content-between { justify-content: space-between; }
.justify-content-center { justify-content: center; }
.align-items-center { align-items: center; }
.align-items-start { align-items: flex-start; }

.mt-1 { margin-top: var(--space-xs); }
.mt-2 { margin-top: var(--space-sm); }
.mt-3 { margin-top: var(--space-md); }
.mt-4 { margin-top: var(--space-lg); }

.mb-1 { margin-bottom: var(--space-xs); }
.mb-2 { margin-bottom: var(--space-sm); }
.mb-3 { margin-bottom: var(--space-md); }
.mb-4 { margin-bottom: var(--space-lg); }

.p-2 { padding: var(--space-sm); }
.p-3 { padding: var(--space-md); }
.p-4 { padding: var(--space-lg); }

.py-3 { padding-top: var(--space-md); padding-bottom: var(--space-md); }
.py-4 { padding-top: var(--space-lg); padding-bottom: var(--space-lg); }
.py-5 { padding-top: var(--space-xl); padding-bottom: var(--space-xl); }

.fw-bold { font-weight: 700; }
.fw-semibold { font-weight: 600; }
.fw-normal { font-weight: 400; }

/* ========================================
   PRINT STYLES
   ======================================== */
@media print {
  .theme-switcher,
  .btn,
  .navbar {
    display: none;
  }
  
  body {
    background-color: white;
    color: black;
  }
  
  .card {
    border: 1px solid #ccc;
    box-shadow: none;
  }
}