/* ============================================================
   writeme ✏️ — Kid-Friendly CSS Design System
   AI English Writing Companion for Kids (Ages 5-14)
   ============================================================ */

/* ---- Google Fonts Import ---- */
@import url('https://fonts.googleapis.com/css2?family=Comic+Neue:wght@400;700&family=Nunito:wght@400;600;700;800&display=swap');

/* ============================================================
   CSS Custom Properties (Theming)
   ============================================================ */
:root {
  /* Brand Colors */
  --primary: #4A90D9;
  --primary-light: #6BA5E7;
  --primary-dark: #3570B0;
  --secondary: #7BC67E;
  --secondary-light: #9FD9A1;
  --secondary-dark: #5DAF60;
  --accent: #FFB347;
  --accent-light: #FFC773;
  --accent-dark: #E89F30;
  --error: #E8836B;
  --error-light: #F0A08C;
  --error-dark: #D46A50;

  /* Backgrounds & Surfaces */
  --bg: #FFF8E7;
  --bg-alt: #FFFDF5;
  --card-bg: #FFFFFF;
  --card-border: #F0E8D5;
  --nav-bg: #FFFFFF;
  --footer-bg: #F5F0E0;

  /* Text */
  --text: #2C3E50;
  --text-secondary: #5D6D7E;
  --text-light: #8E9BAA;
  --text-on-primary: #FFFFFF;
  --text-on-secondary: #FFFFFF;
  --text-on-accent: #2C3E50;

  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(44, 62, 80, 0.08);
  --shadow-md: 0 4px 16px rgba(44, 62, 80, 0.10);
  --shadow-lg: 0 8px 32px rgba(44, 62, 80, 0.12);
  --shadow-color: 0 4px 16px rgba(74, 144, 217, 0.20);

  /* Borders & Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-round: 50%;

  /* Typography */
  --font-heading: 'Comic Neue', 'Nunito', system-ui, -apple-system, sans-serif;
  --font-body: 'Nunito', system-ui, -apple-system, sans-serif;
  --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: 1.375rem;   /* 22px */
  --font-size-2xl: 1.75rem;   /* 28px */
  --font-size-3xl: 2.25rem;   /* 36px */
  --line-height: 1.6;

  /* Spacing */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;
  --space-2xl: 48px;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;

  /* Touch targets (min 44px) */
  --touch-min: 44px;

  /* Stage-specific colors */
  --stage-l1: #7BC67E;
  --stage-l1-light: #A8DCA9;
  --stage-l2: #4A90D9;
  --stage-l2-light: #7EB3E8;
  --stage-l3: #9B59B6;
  --stage-l3-light: #BB8CD4;
  --stage-l4: #F1C40F;
  --stage-l4-light: #F5D657;
}

/* ============================================================
   Reset & Base
   ============================================================ */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-body);
  font-size: var(--font-size-base);
  line-height: var(--line-height);
  color: var(--text);
  background-color: var(--bg);
  background-image: 
    radial-gradient(circle at 5% 15%, rgba(74, 144, 217, 0.06) 0%, transparent 40%),
    radial-gradient(circle at 95% 25%, rgba(123, 198, 126, 0.05) 0%, transparent 40%),
    radial-gradient(circle at 10% 85%, rgba(255, 179, 71, 0.04) 0%, transparent 35%),
    radial-gradient(circle at 90% 75%, rgba(155, 89, 182, 0.04) 0%, transparent 35%);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ============================================================
   Typography
   ============================================================ */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.3;
  color: var(--text);
}

h1 { font-size: var(--font-size-3xl); margin-bottom: var(--space-md); }
h2 { font-size: var(--font-size-2xl); margin-bottom: var(--space-md); }
h3 { font-size: var(--font-size-xl); margin-bottom: var(--space-sm); }
h4 { font-size: var(--font-size-lg); margin-bottom: var(--space-sm); }

p {
  margin-bottom: var(--space-md);
}

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

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

a:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* Emoji inline styling */
.emoji {
  font-style: normal;
  font-size: 1.1em;
  display: inline-block;
}

/* ============================================================
   Container & Layout
   ============================================================ */
.container {
  width: 100%;
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 var(--space-md);
  flex: 1;
  display: flex;
  flex-direction: column;
}

.container-narrow {
  max-width: 800px;
  margin: 0 auto;
}

.container-wide {
  max-width: 100%;
}

.main-content {
  flex: 1;
  padding: var(--space-md) 0 var(--space-lg);
}

/* ============================================================
   Header / Navigation
   ============================================================ */
.header {
  background: var(--nav-bg);
  border-bottom: 2px solid var(--card-border);
  padding: var(--space-xs) 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}

.header-inner {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 var(--space-md);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
}

.logo {
  font-family: var(--font-heading);
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--primary);
  text-decoration: none;
  white-space: nowrap;
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  transition: transform var(--transition-fast);
}

.logo:hover {
  transform: scale(1.03);
  text-decoration: none;
  color: var(--primary-dark);
}

.logo:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* Navigation */
.nav {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
  -ms-overflow-style: none;
}

.nav::-webkit-scrollbar {
  display: none;
}

.nav-link {
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--text-secondary);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-md);
  white-space: nowrap;
  transition: all var(--transition-fast);
  min-height: var(--touch-min);
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  text-decoration: none;
}

.nav-link:hover {
  background: rgba(74, 144, 217, 0.08);
  color: var(--primary);
  text-decoration: none;
}

.nav-link.active {
  background: var(--primary);
  color: var(--text-on-primary);
}

.nav-link:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 2px;
}

/* Mobile menu toggle */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  font-size: var(--font-size-2xl);
  cursor: pointer;
  padding: var(--space-sm);
  min-height: var(--touch-min);
  min-width: var(--touch-min);
  color: var(--text);
  border-radius: var(--radius-sm);
}

.nav-toggle:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 2px;
}

/* ============================================================
   Buttons
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  font-size: var(--font-size-base);
  padding: var(--space-sm) var(--space-md);
  min-height: var(--touch-min);
  min-width: var(--touch-min);
  border: 2px solid transparent;
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: all var(--transition-base);
  text-decoration: none;
  line-height: 1.2;
  white-space: nowrap;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
}

.btn:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 2px;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  pointer-events: none;
}

/* Primary */
.btn-primary {
  background: var(--primary);
  color: var(--text-on-primary);
  border-color: var(--primary);
}

.btn-primary:hover:not(:disabled) {
  background: var(--primary-dark);
  border-color: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: var(--shadow-color);
  text-decoration: none;
}

.btn-primary:active:not(:disabled) {
  transform: translateY(0);
  box-shadow: none;
}

/* Secondary */
.btn-secondary {
  background: var(--secondary);
  color: var(--text-on-secondary);
  border-color: var(--secondary);
}

.btn-secondary:hover:not(:disabled) {
  background: var(--secondary-dark);
  border-color: var(--secondary-dark);
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(123, 198, 126, 0.30);
  text-decoration: none;
}

.btn-secondary:active:not(:disabled) {
  transform: translateY(0);
}

/* Accent */
.btn-accent {
  background: var(--accent);
  color: var(--text-on-accent);
  border-color: var(--accent);
}

.btn-accent:hover:not(:disabled) {
  background: var(--accent-dark);
  border-color: var(--accent-dark);
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(255, 179, 71, 0.30);
  text-decoration: none;
}

.btn-accent:active:not(:disabled) {
  transform: translateY(0);
}

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

.btn-outline:hover:not(:disabled) {
  background: var(--primary);
  color: var(--text-on-primary);
  transform: translateY(-2px);
  text-decoration: none;
}

/* Ghost */
.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
  border-color: transparent;
}

.btn-ghost:hover:not(:disabled) {
  background: rgba(74, 144, 217, 0.08);
  color: var(--primary);
  text-decoration: none;
}

/* Danger */
.btn-danger {
  background: var(--error);
  color: var(--text-on-primary);
  border-color: var(--error);
}

.btn-danger:hover:not(:disabled) {
  background: var(--error-dark);
  border-color: var(--error-dark);
  transform: translateY(-2px);
  text-decoration: none;
}

/* Sizes */
.btn-lg {
  font-size: var(--font-size-base);
  padding: var(--space-sm) var(--space-lg);
  border-radius: var(--radius-xl);
}

.btn-sm {
  font-size: var(--font-size-sm);
  padding: var(--space-xs) var(--space-md);
  border-radius: var(--radius-md);
}

/* Icon-only button */
.btn-icon {
  width: var(--touch-min);
  height: var(--touch-min);
  padding: 0;
  border-radius: var(--radius-round);
}

/* ============================================================
   Inputs & Forms
   ============================================================ */
.input-group {
  margin-bottom: var(--space-lg);
}

.input-label {
  display: block;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: var(--font-size-base);
  color: var(--text);
  margin-bottom: var(--space-sm);
}

.input-label .emoji {
  margin-right: var(--space-xs);
}

.input-field,
.textarea-field,
select.input-field {
  width: 100%;
  font-family: var(--font-body);
  font-size: var(--font-size-base);
  padding: var(--space-md) var(--space-lg);
  background: var(--card-bg);
  border: 2px solid var(--card-border);
  border-radius: var(--radius-lg);
  color: var(--text);
  transition: all var(--transition-fast);
  min-height: var(--touch-min);
  -webkit-appearance: none;
  appearance: none;
}

.input-field:focus,
.textarea-field:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 4px rgba(74, 144, 217, 0.15);
}

.input-field::placeholder,
.textarea-field::placeholder {
  color: var(--text-light);
}

.input-field.error,
.textarea-field.error {
  border-color: var(--error);
  box-shadow: 0 0 0 4px rgba(232, 131, 107, 0.15);
}

.input-hint {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  margin-top: var(--space-xs);
}

.input-error {
  font-size: var(--font-size-sm);
  color: var(--error);
  margin-top: var(--space-xs);
}

/* Textarea */
.textarea-field {
  min-height: 120px;
  resize: vertical;
  line-height: var(--line-height);
}

.textarea-field.large {
  min-height: 240px;
}

/* Select */
select.input-field {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%235D6D7E' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 16px center;
  padding-right: 44px;
}

/* Checkbox & Radio */
.checkbox-group,
.radio-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.checkbox-label,
.radio-label {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: var(--font-size-base);
  cursor: pointer;
  min-height: var(--touch-min);
  padding: var(--space-xs) 0;
}

.checkbox-label input[type="checkbox"],
.radio-label input[type="radio"] {
  width: 20px;
  height: 20px;
  accent-color: var(--primary);
  cursor: pointer;
}

/* ============================================================
   Cards
   ============================================================ */
.card {
  background: var(--card-bg);
  border: 2px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: var(--space-md);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
}

.card:hover {
  box-shadow: var(--shadow-md);
}

.card-interactive {
  cursor: pointer;
}

.card-interactive:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: var(--primary-light);
}

.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-md);
  border-bottom: 2px solid var(--card-border);
}

.card-body {
  flex: 1;
}

.card-footer {
  margin-top: var(--space-md);
  padding-top: var(--space-md);
  border-top: 2px solid var(--card-border);
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: var(--space-sm);
}

/* ============================================================
   Progress Bar (WRITE loop phases)
   ============================================================ */
.progress-bar {
  width: 100%;
  height: 12px;
  background: var(--card-border);
  border-radius: 99px;
  overflow: hidden;
  position: relative;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--secondary), var(--primary));
  border-radius: 99px;
  transition: width var(--transition-slow);
  position: relative;
}

.progress-fill::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
  animation: shimmer 2s infinite;
}

@keyframes shimmer {
  0% { transform: translateX(-100%); }
  100% { transform: translateX(100%); }
}

/* ============================================================
   Phase Indicator (6 steps for WRITE mode)
   ============================================================ */
.phase-indicator {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0;
  padding: var(--space-sm) 0;
  width: 100%;
}

.phase-step {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  flex: 1;
  position: relative;
  z-index: 1;
}

.phase-circle {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-round);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: var(--font-size-xs);
  background: var(--card-border);
  color: var(--text-light);
  border: 2px solid var(--card-border);
  transition: all var(--transition-base);
  position: relative;
  z-index: 2;
}

.phase-step.active .phase-circle {
  background: var(--primary);
  color: var(--text-on-primary);
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(74, 144, 217, 0.2);
  transform: scale(1.1);
}

.phase-step.completed .phase-circle {
  background: var(--secondary);
  color: var(--text-on-secondary);
  border-color: var(--secondary);
}

.phase-label {
  font-size: 0.65rem;
  font-weight: 600;
  color: var(--text-light);
  text-align: center;
  white-space: nowrap;
}

.phase-step.active .phase-label {
  color: var(--primary);
  font-weight: 700;
}

.phase-step.completed .phase-label {
  color: var(--secondary);
}

/* Connector line between phases */
.phase-connector {
  flex: 1;
  height: 2px;
  background: var(--card-border);
  margin: 0 -1px;
  align-self: center;
  margin-bottom: 22px;
  position: relative;
  z-index: 1;
}

.phase-connector.completed {
  background: var(--secondary);
}

/* ============================================================
   Error Passport Display
   ============================================================ */
.error-passport {
  display: flex;
  gap: var(--space-md);
  flex-wrap: wrap;
  padding: var(--space-md);
  background: var(--card-bg);
  border-radius: var(--radius-lg);
  border: 2px solid var(--card-border);
}

.error-status {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  font-weight: 600;
  min-height: var(--touch-min);
}

.error-status.active {
  background: rgba(232, 131, 107, 0.12);
  color: var(--error-dark);
  border: 2px solid var(--error);
}

.error-status.watching {
  background: rgba(255, 179, 71, 0.12);
  color: var(--accent-dark);
  border: 2px solid var(--accent);
}

.error-status.mastered {
  background: rgba(123, 198, 126, 0.12);
  color: var(--secondary-dark);
  border: 2px solid var(--secondary);
}

.error-status .emoji {
  font-size: 1.3em;
}

/* ============================================================
   Badges & Stars
   ============================================================ */
.badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: 2px var(--space-sm);
  border-radius: 99px;
  font-size: var(--font-size-xs);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.badge-primary {
  background: rgba(74, 144, 217, 0.12);
  color: var(--primary);
}

.badge-secondary {
  background: rgba(123, 198, 126, 0.12);
  color: var(--secondary-dark);
}

.badge-accent {
  background: rgba(255, 179, 71, 0.12);
  color: var(--accent-dark);
}

.badge-error {
  background: rgba(232, 131, 107, 0.12);
  color: var(--error-dark);
}

.star {
  display: inline-flex;
  align-items: center;
  font-size: var(--font-size-xl);
  transition: transform var(--transition-fast);
}

.star.earned {
  animation: starPop 0.3s ease;
}

@keyframes starPop {
  0% { transform: scale(0); }
  50% { transform: scale(1.4); }
  100% { transform: scale(1); }
}

.star-rating {
  display: flex;
  gap: 2px;
}

/* ============================================================
   Modal Overlay
   ============================================================ */
.modal-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(44, 62, 80, 0.5);
  backdrop-filter: blur(4px);
  z-index: 1000;
  justify-content: center;
  align-items: center;
  padding: var(--space-md);
  animation: fadeIn 0.2s ease;
}

.modal-overlay.open {
  display: flex;
}

.modal {
  background: var(--card-bg);
  border-radius: var(--radius-xl);
  padding: var(--space-xl);
  max-width: 500px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: var(--shadow-lg);
  animation: slideUp 0.3s ease;
  position: relative;
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-lg);
}

.modal-title {
  font-family: var(--font-heading);
  font-size: var(--font-size-xl);
  font-weight: 700;
}

.modal-close {
  background: none;
  border: none;
  font-size: var(--font-size-2xl);
  cursor: pointer;
  color: var(--text-secondary);
  width: var(--touch-min);
  height: var(--touch-min);
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-round);
  transition: all var(--transition-fast);
}

.modal-close:hover {
  background: rgba(0, 0, 0, 0.05);
  color: var(--text);
}

.modal-close:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 2px;
}

.modal-body {
  margin-bottom: var(--space-lg);
}

.modal-footer {
  display: flex;
  justify-content: flex-end;
  gap: var(--space-sm);
}

/* ============================================================
   Timer Component
   ============================================================ */
.timer {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  font-family: var(--font-heading);
  font-size: var(--font-size-lg);
  font-weight: 700;
  color: var(--text);
  padding: var(--space-sm) var(--space-md);
  background: var(--card-bg);
  border: 2px solid var(--card-border);
  border-radius: var(--radius-lg);
  min-height: var(--touch-min);
}

.timer.running {
  border-color: var(--primary-light);
  color: var(--primary);
}

.timer .emoji {
  font-size: 1.2em;
}

/* ============================================================
   Word Counter
   ============================================================ */
.word-counter {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  font-weight: 600;
}

.word-counter .count {
  font-family: var(--font-heading);
  font-size: var(--font-size-lg);
  color: var(--text);
  min-width: 28px;
  text-align: center;
}

.word-counter .count.warning {
  color: var(--accent);
}

.word-counter .count.limit {
  color: var(--error);
}

/* ============================================================
   Side-by-Side Comparison (REWRITE phase)
   ============================================================ */
.comparison-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-lg);
  margin: var(--space-lg) 0;
}

.comparison-panel {
  background: var(--card-bg);
  border: 2px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  min-height: 200px;
}

.comparison-panel.original {
  border-color: var(--primary-light);
  background: rgba(74, 144, 217, 0.03);
}

.comparison-panel.rewritten {
  border-color: var(--secondary);
  background: rgba(123, 198, 126, 0.03);
}

.comparison-label {
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  font-weight: 700;
  color: var(--text-secondary);
  margin-bottom: var(--space-sm);
  text-transform: uppercase;
  letter-spacing: 1px;
}

.comparison-content {
  font-size: var(--font-size-base);
  line-height: var(--line-height);
  white-space: pre-wrap;
}

/* Diff highlighting */
.diff-added {
  background: rgba(123, 198, 126, 0.2);
  border-radius: 3px;
  padding: 0 2px;
}

.diff-removed {
  background: rgba(232, 131, 107, 0.2);
  border-radius: 3px;
  padding: 0 2px;
  text-decoration: line-through;
}

/* ============================================================
   Hint Ladder (4 levels)
   ============================================================ */
.hint-ladder {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  padding: var(--space-md);
  background: var(--card-bg);
  border: 2px solid var(--card-border);
  border-radius: var(--radius-lg);
}

.hint-step {
  display: flex;
  align-items: flex-start;
  gap: var(--space-sm);
  padding: var(--space-sm);
  border-radius: var(--radius-md);
  transition: background var(--transition-fast);
  cursor: pointer;
}

.hint-step:hover {
  background: rgba(74, 144, 217, 0.05);
}

.hint-step.revealed {
  background: rgba(74, 144, 217, 0.08);
}

.hint-level {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: var(--radius-round);
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: var(--font-size-xs);
  flex-shrink: 0;
}

.hint-level.tip {
  background: rgba(74, 144, 217, 0.15);
  color: var(--primary);
}

.hint-level.clue {
  background: rgba(123, 198, 126, 0.15);
  color: var(--secondary-dark);
}

.hint-level.example {
  background: rgba(255, 179, 71, 0.15);
  color: var(--accent-dark);
}

.hint-level.answer {
  background: rgba(232, 131, 107, 0.15);
  color: var(--error-dark);
}

.hint-text {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  line-height: 1.5;
}

.hint-step.revealed .hint-text {
  color: var(--text);
}

/* ============================================================
   Flash Messages
   ============================================================ */
.flash-messages {
  position: fixed;
  top: 80px;
  right: var(--space-md);
  z-index: 999;
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  max-width: 360px;
}

.flash-message {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-lg);
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: var(--font-size-sm);
  box-shadow: var(--shadow-md);
  animation: slideIn 0.3s ease;
  border: 2px solid transparent;
  min-height: var(--touch-min);
}

.flash-message.success {
  background: rgba(123, 198, 126, 0.15);
  color: var(--secondary-dark);
  border-color: var(--secondary);
}

.flash-message.error {
  background: rgba(232, 131, 107, 0.15);
  color: var(--error-dark);
  border-color: var(--error);
}

.flash-message.info {
  background: rgba(74, 144, 217, 0.15);
  color: var(--primary-dark);
  border-color: var(--primary);
}

.flash-message.warning {
  background: rgba(255, 179, 71, 0.15);
  color: var(--accent-dark);
  border-color: var(--accent);
}

.flash-close {
  background: none;
  border: none;
  cursor: pointer;
  font-size: var(--font-size-lg);
  margin-left: auto;
  opacity: 0.6;
  padding: 2px;
  min-height: var(--touch-min);
  min-width: var(--touch-min);
  display: flex;
  align-items: center;
  justify-content: center;
}

.flash-close:hover {
  opacity: 1;
}

@keyframes slideIn {
  from {
    transform: translateX(100%);
    opacity: 0;
  }
  to {
    transform: translateX(0);
    opacity: 1;
  }
}

/* ============================================================
   Footer
   ============================================================ */
.footer {
  background: var(--footer-bg);
  border-top: 2px solid var(--card-border);
  padding: var(--space-sm) 0;
  margin-top: auto;
  text-align: center;
}

.footer-text {
  font-family: var(--font-heading);
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
}

.footer-text .emoji {
  font-size: 1.1em;
}

/* ============================================================
   Stage-specific Theme Overrides
   ============================================================ */
.stage-l1 {
  --stage-color: var(--stage-l1);
  --stage-color-light: var(--stage-l1-light);
}

.stage-l2 {
  --stage-color: var(--stage-l2);
  --stage-color-light: var(--stage-l2-light);
}

.stage-l3 {
  --stage-color: var(--stage-l3);
  --stage-color-light: var(--stage-l3-light);
}

.stage-l4 {
  --stage-color: var(--stage-l4);
  --stage-color-light: var(--stage-l4-light);
}

/* Stage accent banner */
.stage-banner {
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-md);
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: var(--font-size-sm);
  text-align: center;
}

.stage-l1 .stage-banner,
.stage-banner.l1 {
  background: var(--stage-l1);
  color: var(--text-on-secondary);
}

.stage-l2 .stage-banner,
.stage-banner.l2 {
  background: var(--stage-l2);
  color: var(--text-on-primary);
}

.stage-l3 .stage-banner,
.stage-banner.l3 {
  background: var(--stage-l3);
  color: var(--text-on-primary);
}

.stage-l4 .stage-banner,
.stage-banner.l4 {
  background: var(--stage-l4);
  color: var(--text);
}

/* ============================================================
   Animations
   ============================================================ */
@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

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

@keyframes bounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-12px); }
}

@keyframes pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.05); }
}

@keyframes spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

@keyframes confetti {
  0% {
    transform: translateY(0) rotate(0deg);
    opacity: 1;
  }
  100% {
    transform: translateY(400px) rotate(720deg);
    opacity: 0;
  }
}

/* Animation utility classes */
.animate-fade-in {
  animation: fadeIn var(--transition-base) ease;
}

.animate-fade-in-up {
  animation: fadeInUp 0.4s ease;
}

.animate-slide-up {
  animation: slideUp 0.3s ease;
}

.animate-bounce {
  animation: bounce 0.6s ease;
}

.animate-pulse {
  animation: pulse 2s ease infinite;
}

/* Staggered children */
.stagger > * {
  opacity: 0;
  animation: fadeInUp 0.4s ease forwards;
}

.stagger > *:nth-child(1) { animation-delay: 0.05s; }
.stagger > *:nth-child(2) { animation-delay: 0.10s; }
.stagger > *:nth-child(3) { animation-delay: 0.15s; }
.stagger > *:nth-child(4) { animation-delay: 0.20s; }
.stagger > *:nth-child(5) { animation-delay: 0.25s; }
.stagger > *:nth-child(6) { animation-delay: 0.30s; }
.stagger > *:nth-child(7) { animation-delay: 0.35s; }
.stagger > *:nth-child(8) { animation-delay: 0.40s; }

/* ============================================================
   Confetti / Celebration
   ============================================================ */
.celebration-container {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 9999;
  overflow: hidden;
}

.confetti-piece {
  position: absolute;
  width: 10px;
  height: 10px;
  border-radius: 2px;
  animation: confettiFall linear forwards;
}

@keyframes confettiFall {
  0% {
    transform: translateY(-10px) rotate(0deg);
    opacity: 1;
  }
  100% {
    transform: translateY(100vh) rotate(720deg);
    opacity: 0;
  }
}

/* ============================================================
   Emoji PIN Input
   ============================================================ */
.emoji-pin {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-lg);
}

.emoji-pin-display {
  display: flex;
  gap: var(--space-sm);
  padding: var(--space-md);
  background: var(--card-bg);
  border: 3px solid var(--card-border);
  border-radius: var(--radius-lg);
  min-height: 60px;
  align-items: center;
}

.emoji-pin-slot {
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5em;
  background: rgba(74, 144, 217, 0.05);
  border: 2px dashed var(--card-border);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.emoji-pin-slot.filled {
  border-style: solid;
  border-color: var(--primary);
  background: rgba(74, 144, 217, 0.1);
}

.emoji-pin-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-sm);
  max-width: 280px;
}

.emoji-pin-btn {
  width: 60px;
  height: 60px;
  border: 2px solid var(--card-border);
  border-radius: var(--radius-md);
  background: var(--card-bg);
  font-size: 1.5em;
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
}

.emoji-pin-btn:hover {
  background: rgba(74, 144, 217, 0.08);
  border-color: var(--primary);
  transform: scale(1.1);
}

.emoji-pin-btn:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 2px;
}

/* ============================================================
   Loading / Spinner
   ============================================================ */
.spinner {
  display: inline-block;
  width: 24px;
  height: 24px;
  border: 3px solid var(--card-border);
  border-top-color: var(--primary);
  border-radius: var(--radius-round);
  animation: spin 0.8s linear infinite;
}

.spinner-lg {
  width: 40px;
  height: 40px;
  border-width: 4px;
}

.loading-overlay {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-md);
  padding: var(--space-2xl);
}

/* ============================================================
   Auth / Login
   ============================================================ */
.auth-container {
  max-width: 400px;
  margin: var(--space-2xl) auto;
  text-align: center;
}

.auth-card {
  background: var(--card-bg);
  border: 2px solid var(--card-border);
  border-radius: var(--radius-xl);
  padding: var(--space-xl);
  box-shadow: var(--shadow-md);
}

.auth-logo {
  font-family: var(--font-heading);
  font-size: var(--font-size-3xl);
  margin-bottom: var(--space-lg);
}

.auth-logo .emoji {
  font-size: 1.2em;
}

/* ============================================================
   Writing Area
   ============================================================ */
.writing-area {
  background: var(--card-bg);
  border: 2px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  box-shadow: var(--shadow-sm);
}

.writing-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-sm);
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-md);
  border-bottom: 2px solid var(--card-border);
  flex-wrap: wrap;
}

.writing-toolbar-group {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

/* ============================================================
   Responsive: Tablet
   ============================================================ */
@media (max-width: 768px) {
  .container {
    padding: 0 var(--space-sm);
  }

  h1 { font-size: var(--font-size-2xl); }
  h2 { font-size: var(--font-size-xl); }
  h3 { font-size: var(--font-size-lg); }

  .nav {
    gap: 2px;
  }

  .nav-link {
    font-size: var(--font-size-xs);
    padding: var(--space-sm) var(--space-sm);
  }

  .comparison-layout {
    grid-template-columns: 1fr;
  }

  .phase-circle {
    width: 32px;
    height: 32px;
    font-size: var(--font-size-xs);
  }

  .phase-label {
    font-size: 10px;
  }

  .phase-connector {
    margin-bottom: 24px;
  }

  .modal {
    padding: var(--space-lg);
    max-width: 100%;
    margin: var(--space-sm);
  }

  .flash-messages {
    left: var(--space-md);
    right: var(--space-md);
    max-width: none;
  }

  .emoji-pin-grid {
    grid-template-columns: repeat(4, 1fr);
    max-width: 240px;
  }

  .emoji-pin-btn {
    width: 50px;
    height: 50px;
    font-size: 1.3em;
  }

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

/* ============================================================
   Responsive: Phone
   ============================================================ */
@media (max-width: 480px) {
  :root {
    --font-size-base: 0.9375rem; /* 15px */
  }

  .container {
    padding: 0 var(--space-sm);
  }

  h1 { font-size: var(--font-size-xl); }
  h2 { font-size: var(--font-size-lg); }

  .nav-toggle {
    display: block;
  }

  .nav {
    display: none;
    flex-direction: column;
    width: 100%;
    padding: var(--space-sm) 0;
    gap: 2px;
  }

  .nav.open {
    display: flex;
  }

  .nav-link {
    width: 100%;
    justify-content: center;
    font-size: var(--font-size-base);
    padding: var(--space-md);
  }

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

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

  .btn {
    font-size: var(--font-size-sm);
    padding: var(--space-sm) var(--space-md);
  }

  .btn-lg {
    font-size: var(--font-size-base);
    padding: var(--space-md) var(--space-lg);
  }

  .phase-circle {
    width: 28px;
    height: 28px;
    font-size: 10px;
  }

  .phase-label {
    display: none;
  }

  .phase-connector {
    margin-bottom: 0;
  }

  .error-passport {
    flex-direction: column;
  }

  .writing-toolbar {
    flex-direction: column;
    align-items: stretch;
  }

  .writing-toolbar-group {
    justify-content: center;
  }

  .emoji-pin-grid {
    grid-template-columns: repeat(4, 1fr);
    max-width: 200px;
  }

  .emoji-pin-btn {
    width: 44px;
    height: 44px;
    font-size: 1.2em;
  }
}

/* ============================================================
   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: 0;
}

/* Focus visible for keyboard users */
:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 2px;
}

/* High contrast mode adjustments */
@media (prefers-contrast: high) {
  :root {
    --primary: #2B6CB0;
    --secondary: #38A169;
    --accent: #D69E2E;
    --error: #C53030;
    --text: #1A202C;
    --card-border: #4A5568;
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.15);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.25);
  }

  .card {
    border-width: 2px;
  }

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

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  html {
    scroll-behavior: auto;
  }
}

/* ============================================================
   Print Styles
   ============================================================ */
@media print {
  .header,
  .footer,
  .nav,
  .flash-messages,
  .modal-overlay,
  .celebration-container {
    display: none !important;
  }

  .container {
    max-width: 100%;
    padding: 0;
  }

  .card {
    box-shadow: none;
    border: 1px solid #ccc;
    break-inside: avoid;
  }
}