/* Header & Navigation */
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 0;
  margin-bottom: 2rem;
  position: sticky;
  top: 0;
  background-color: var(--bg-color);
  z-index: 100;
  transition: transform 0.3s ease, opacity 0.3s ease;
}

header.header-hidden {
  transform: translateY(-100%);
  opacity: 0;
  pointer-events: none;
}

.nav-buttons {
  display: flex;
  gap: 0.5rem;
}

/* Common Buttons */
.btn-primary {
  background-color: var(--accent-color);
  color: white;
  padding: 0.75rem 1.5rem;
}

.btn-outline {
  background-color: transparent;
  border: 2px solid var(--accent-color);
  color: var(--accent-color);
  padding: 0.75rem 1.5rem;
}

.btn-icon {
  background-color: var(--surface-color);
  color: var(--text-primary);
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border-color);
}

/* Quiz UI Components */
.quiz-card {
  background-color: var(--surface-color);
  border-radius: 16px;
  padding: 2rem;
  box-shadow: var(--shadow);
  width: 100%;
  max-width: 500px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  max-height: 80vh; /* Limit card height to viewport */
}

.large-kana {
  font-size: clamp(2.5rem, 12vw, 7rem);
  font-weight: 700;
  line-height: 1.2;
  white-space: nowrap;
  max-width: 100%;
  text-align: center;
  overflow: hidden;
}

.composition-display {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: 0.5rem;
  color: var(--accent-color);
  min-height: 2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  white-space: nowrap;
  max-width: 100%;
  overflow: hidden;
}

.romaji-label {
  font-size: clamp(2rem, 10vw, 4rem);
  font-weight: 600;
  color: var(--text-primary);
  flex-shrink: 0;
  white-space: nowrap;
  max-width: 100%;
  text-align: center;
  overflow: hidden;
}

.scoreboard {
  display: flex;
  flex-direction: row;
  justify-content: center;
  flex-wrap: wrap;
  width: 100%;
  font-weight: 600;
  color: var(--text-secondary);
  gap: 1rem;
  flex-shrink: 0;
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.05rem;
}

/* Grid for Mode 2 (Romaji -> Kana) */
.kana-picker {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(60px, 1fr));
  gap: 0.5rem;
  width: 100%;
  flex: 1; /* Take remaining space */
  overflow-y: auto;
  padding: 0.5rem;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  background-color: rgba(0, 0, 0, 0.05);
}

.picker-item {
  aspect-ratio: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  background-color: var(--surface-color);
  color: var(--accent-color);
  border: 1px solid var(--border-color);
  border-radius: 8px;
}

.picker-item:hover {
  background-color: var(--accent-color);
  color: white;
  border-color: var(--accent-color);
}

/* Overlay / Reference Table */
.overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.8);
  display: none;
  z-index: 1000;
  padding: 2rem;
  overflow-y: auto;
}

.overlay.active {
  display: block;
}

.overlay-content {
  background-color: var(--surface-color);
  padding: 2rem;
  border-radius: 16px;
  max-width: 1000px;
  margin: 0 auto;
  position: relative;
}

.close-overlay {
  position: absolute;
  top: 1rem;
  right: 1rem;
}

.ref-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 0.5rem;
}

.ref-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 0.5rem;
  border: 1px solid var(--border-color);
  border-radius: 4px;
}

.ref-item .kana { font-size: 1.25rem; font-weight: 700; }
.ref-item .romaji { font-size: 0.875rem; color: var(--text-secondary); }

/* Notifications */
.notification-container {
    position: fixed;
    top: 1rem;
    left: 50%;
    transform: translateX(-50%);
    z-index: 2000;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    pointer-events: none;
    width: 90%;
    max-width: 400px;
}

.notification {
    background-color: var(--surface-color);
    color: var(--text-primary);
    padding: 1rem 1.5rem;
    border-radius: 12px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
    border: 1px solid var(--border-color);
    font-size: 1rem;
    font-weight: 600;
    opacity: 0;
    transform: translateY(-2rem);
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    pointer-events: auto;
    text-align: center;
}

.notification.show {
    opacity: 1;
    transform: translateY(0);
}

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

.notification.wrong {
    background-color: var(--error-color);
    color: white;
    border-color: var(--error-color);
}

/* Incremental Learning Mode */

.phase-map {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  width: 100%;
  max-width: 500px;
}

.phase-card {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem;
  border-radius: 12px;
  border: 2px solid var(--border-color);
  background-color: var(--surface-color);
  box-shadow: var(--shadow);
  cursor: pointer;
  transition: transform 0.1s, box-shadow 0.1s;
}

.phase-card:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(0,0,0,0.12);
}

.phase-card:active {
  transform: scale(0.98);
}

.phase-card.locked {
  opacity: 0.5;
}

.phase-hint {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
  white-space: nowrap;
  flex-shrink: 0;
}

.phase-card.completed {
  border-color: var(--success-color);
}

.phase-card.current {
  border-color: var(--accent-color);
}

.phase-number {
  width: 2.5rem;
  height: 2.5rem;
  border-radius: 50%;
  background-color: var(--accent-color);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.875rem;
  flex-shrink: 0;
}

.phase-card.locked .phase-number {
  background-color: var(--text-secondary);
}

.phase-card.completed .phase-number {
  background-color: var(--success-color);
}

.phase-info {
  flex: 1;
  min-width: 0;
}

.phase-label {
  font-weight: 600;
  margin-bottom: 0.2rem;
}

.phase-symbols-preview {
  font-size: 1rem;
  color: var(--text-secondary);
  letter-spacing: 0.1rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.phase-accuracy {
  font-size: 0.8rem;
  color: var(--success-color);
  font-weight: 600;
  margin-top: 0.1rem;
}

.intro-symbols-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(80px, 1fr));
  gap: 0.75rem;
  width: 100%;
  max-width: 500px;
}

.intro-symbol-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 0.75rem 0.5rem;
  border-radius: 12px;
  border: 2px solid var(--border-color);
  background-color: var(--surface-color);
  box-shadow: var(--shadow);
}

.intro-symbol-card .kana {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
}

.intro-symbol-card .romaji {
  font-size: 0.8rem;
  color: var(--text-secondary);
  font-weight: 600;
}

.stage-indicator {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
  justify-content: center;
}

.stage-badge {
  background-color: var(--accent-color);
  color: white;
  padding: 0.3rem 0.75rem;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05rem;
  white-space: nowrap;
}

.stage-progress-text {
  font-size: 0.875rem;
  color: var(--text-secondary);
  font-weight: 600;
}

.tier-btn {
  padding: 0.5rem 0;
  font-size: 0.875rem;
}

.tier-btn-active {
  background-color: var(--accent-color);
  color: white;
  border-color: var(--accent-color);
}

.phase-complete-card {
  text-align: center;
  gap: 1rem;
}

.phase-complete-title {
  font-size: 2rem;
  font-weight: 700;
}

.phase-complete-stats {
  font-size: 1.25rem;
  color: var(--text-secondary);
}

/* Dictionary Style */
.dictionary-section {
  max-width: 600px;
  width: 100%;
  margin-top: 2rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  padding: 1rem;
  border-top: 1px solid var(--border-color);
}

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

.headword {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
}

.pronunciation {
  font-weight: 400;
  color: var(--text-secondary);
  font-style: normal;
  font-size: 1rem;
  margin-left: 0.5rem;
}

.definition {
  font-family: 'Georgia', 'Times New Roman', serif;
  font-size: 1.05rem;
  line-height: 1.5;
  color: var(--text-primary);
}

.definition em {
  color: var(--text-secondary);
  font-family: 'Inter', sans-serif;
  font-size: 0.9rem;
  margin-right: 0.25rem;
}