/* ===== GRE Vocabulary Builder Styles ===== */

.hero-stats {
  display: flex;
  gap: 0.75rem;
  justify-content: center;
  flex-wrap: wrap;
}

.stat-badge {
  background: var(--primary-color);
  color: white;
  padding: 0.4rem 1rem;
  border-radius: 20px;
  font-size: 0.875rem;
  font-weight: 500;
}

.gre-controls {
  margin: 2rem 0;
  padding: 1.5rem;
  background: var(--bg-secondary);
  border-radius: var(--radius);
  border: 1px solid var(--border-color);
}

.search-bar-container {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.gre-search {
  flex: 1;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  font-size: 1rem;
  font-family: inherit;
  transition: var(--transition);
}

.gre-search:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.2);
}

.gre-filters {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  align-items: center;
}

.gre-select {
  padding: 0.5rem 1rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  font-size: 0.875rem;
  background: var(--bg-color);
  cursor: pointer;
  transition: var(--transition);
}

.gre-select:focus {
  outline: none;
  border-color: var(--primary-color);
}

.mode-toggle {
  display: flex;
  gap: 0.5rem;
  margin-top: 1rem;
}

.mode-toggle .btn {
  flex: 1;
}

.mode-active {
  background: var(--primary-color) !important;
  color: white !important;
  border-color: var(--primary-color);
}

.progress-container {
  margin: 1.5rem 0;
  padding: 1rem;
  background: var(--bg-color);
  border-radius: var(--radius);
  border: 1px solid var(--border-color);
}

.progress-header {
  display: flex;
  justify-content: space-between;
  margin-bottom: 0.5rem;
  font-size: 0.875rem;
  color: var(--text-light);
}

.progress-bar {
  width: 100%;
  height: 12px;
  background: var(--border-color);
  border-radius: 10px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
  border-radius: 10px;
  transition: width 0.5s ease;
  width: 0%;
}

.results-info {
  margin: 1rem 0;
  font-size: 0.875rem;
  color: var(--text-light);
}

.loading-message {
  text-align: center;
  padding: 3rem;
  color: var(--text-light);
    font-size: 1.1rem;
}

/* Word Cards */
.gre-word-card {
  background: var(--bg-color);
  border: 1px solid var(--border-color);
  border-left: 4px solid var(--primary-color);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 1rem;
  box-shadow: var(--shadow);
  transition: var(--transition);
  position: relative;
}

.gre-word-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateX(4px);
}

.gre-word-card.learned {
  border-left-color: #10b981;
  background: rgba(16, 185, 129, 0.03);
}

.gre-word-header {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
  flex-wrap: wrap;
}

.gre-word-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-color);
  margin: 0;
  flex: 1;
}

.gre-word-pos {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  background: var(--primary-color);
  color: white;
  padding: 0.25rem 0.75rem;
  border-radius: 12px;
  font-weight: 600;
  white-space: nowrap;
}

.gre-word-rank {
  font-size: 0.75rem;
  color: var(--text-light);
  background: var(--bg-secondary);
  padding: 0.25rem 0.5rem;
  border-radius: 6px;
}

.gre-tier-badge {
  font-size: 0.7rem;
  padding: 0.25rem 0.6rem;
  border-radius: 10px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  white-space: nowrap;
}

.tier-essential { background: rgba(239, 68, 68, 0.15); color: #ef4444; }
.tier-high { background: rgba(249, 115, 22, 0.15); color: #f97316; }
.tier-medium { background: rgba(59, 130, 246, 0.15); color: #3b82f6; }
.tier-review { background: rgba(34, 197, 94, 0.15); color: #22c55e; }

.gre-learned-btn {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  background: transparent;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 0.3rem 0.6rem;
  font-size: 0.75rem;
  cursor: pointer;
  transition: var(--transition);
}

.gre-learned-btn:hover { background: var(--primary-color); color: white; }
.gre-learned-btn.learned { background: #10b981; color: white; border-color: #10b981; }

.gre-word-definition {
  font-size: 1.05rem;
  color: var(--text-color);
  margin-bottom: 0.75rem;
  font-weight: 500;
}

.gre-synonyms, .gre-antonyms {
  margin: 0.5rem 0;
  font-size: 0.875rem;
}

.gre-synonyms strong, .gre-antonyms strong {
  color: var(--text-color);
  font-weight: 600;
}

.gre-synonym-list, .gre-antonym-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem;
  margin-top: 0.25rem;
}

.gre-synonym-chip, .gre-antonym-chip {
  background: var(--bg-secondary);
  padding: 0.15rem 0.6rem;
  border-radius: 12px;
  font-size: 0.8rem;
  color: var(--text-light);
}

.gre-usage {
  background: var(--bg-secondary);
  border-radius: var(--radius);
  padding: 0.75rem 1rem;
  margin: 0.75rem 0;
  border-left: 3px solid var(--primary-color);
}

.gre-usage-where { font-size: 0.85rem; margin-bottom: 0.5rem; }
.gre-usage-where::before { content: "✓ "; color: #10b981; font-weight: bold; }
.gre-usage-where-not { font-size: 0.85rem; }
.gre-usage-where-not::before { content: "✕ "; color: #ef4444; font-weight: bold; }

.gre-example {
  font-style: italic;
  color: var(--text-light);
  margin: 0.4rem 0;
  padding-left: 0.75rem;
  border-left: 2px solid var(--border-color);
}

.gre-examples { margin-top: 0.75rem; }

.gre-quiz-container { max-width: 700px; margin: 0 auto; }
.gre-quiz-card {
  background: var(--bg-color);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 2rem;
  margin-bottom: 1.5rem;
  box-shadow: var(--shadow-lg);
}

.gre-quiz-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.5rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border-color);
}

.gre-quiz-progress { font-size: 0.875rem; color: var(--text-light); }
.gre-quiz-question {
  font-size: 1.5rem; font-weight: 600; margin-bottom: 1.5rem;
  text-align: center; color: var(--text-color);
}

.gre-quiz-options {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
}

.gre-quiz-option {
  background: var(--bg-secondary);
  border: 2px solid var(--border-color);
  border-radius: var(--radius);
  padding: 1rem;
  font-size: 1rem;
  cursor: pointer;
  transition: var(--transition);
  text-align: center;
  font-weight: 500;
}

.gre-quiz-option:hover {
  background: var(--primary-color); color: white;
  border-color: var(--primary-color); transform: translateY(-2px);
}

.gre-quiz-option.correct { background: rgba(16, 185, 129, 0.2); border-color: #10b981; }
.gre-quiz-option.incorrect { background: rgba(239, 68, 68, 0.2); border-color: #ef4444; }
.gre-quiz-option.disabled { cursor: default; }
.gre-quiz-option.disabled:hover {
  background: var(--bg-secondary); color: var(--text-color);
  border-color: var(--border-color); transform: none;
}

.gre-quiz-answer {
  background: var(--bg-secondary);
  border-radius: var(--radius);
  padding: 1rem;
  margin: 1rem 0;
  font-size: 0.95rem;
}
.gre-quiz-answer strong { color: var(--text-color); }
.gre-quiz-nav { display: flex; gap: 1rem; justify-content: center; }
.gre-empty { text-align: center; padding: 3rem; color: var(--text-light); }
.gre-empty h3 { color: var(--text-color); margin-bottom: 0.5rem; }
.gre-results { background: var(--bg-color); border: 1px solid var(--border-color);
  border-radius: var(--radius); padding: 2rem; text-align: center; margin: 2rem 0; }
.gre-results .stat { font-size: 2rem; font-weight: 700; color: var(--primary-color); }
.gre-results .label { font-size: 0.875rem; color: var(--text-light); }

@media (max-width: 768px) {
  .gre-quiz-options { grid-template-columns: 1fr; }
  .gre-word-title { font-size: 1.25rem; }
  .gre-controls { padding: 1rem; }
}

/* ===== Alphabet Navigation ===== */

/* Sticky A-Z quick-jump bar, pinned below the site nav */
.gre-alphabet-bar {
  position: sticky;
  top: var(--nav-height, 64px);
  z-index: 90;
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 0.5rem;
  margin-bottom: 1.5rem;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow-x: auto;
  scrollbar-width: thin;
  overscroll-behavior-x: contain;
}

.gre-alphabet-bar::-webkit-scrollbar { height: 6px; }
.gre-alphabet-bar::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 3px;
}

.gre-alpha-btn {
  flex: 0 0 auto;
  min-width: 34px;
  height: 34px;
  border: 1px solid transparent;
  border-radius: 8px;
  background: transparent;
  color: var(--text-light);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
}

.gre-alpha-btn:hover:not(:disabled) {
  background: rgba(37, 99, 235, 0.08);
  color: var(--primary-color);
  border-color: rgba(37, 99, 235, 0.2);
}

.gre-alpha-btn.active {
  background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
  color: white;
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.35);
}

.gre-alpha-btn.disabled {
  opacity: 0.3;
  cursor: not-allowed;
  text-decoration: line-through;
}

/* Letter groups */
.gre-letter-group {
  scroll-margin-top: calc(var(--nav-height, 64px) + var(--alpha-bar-height, 54px) + 16px);
}

.gre-letter-header {
  position: sticky;
  top: calc(var(--nav-height, 64px) + var(--alpha-bar-height, 54px));
  z-index: 40;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.55rem 1rem;
  margin: 1.5rem 0 1rem;
  background: linear-gradient(90deg, var(--bg-secondary), rgba(248, 250, 252, 0.9));
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  border: 1px solid var(--border-color);
  border-left: 4px solid var(--primary-color);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.gre-letter {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 2.25rem;
  height: 2.25rem;
  background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
  color: white;
  border-radius: 10px;
  font-size: 1.15rem;
  font-weight: 800;
}

.gre-letter-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-light);
  margin: 0;
  flex: 1;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.gre-letter-count {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--primary-color);
  background: rgba(37, 99, 235, 0.08);
  padding: 0.25rem 0.65rem;
  border-radius: 12px;
  white-space: nowrap;
}

/* Floating back-to-top button */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 48px;
  height: 48px;
  border: none;
  border-radius: 50%;
  background: var(--primary-color);
  color: white;
  font-size: 1.3rem;
  line-height: 1;
  cursor: pointer;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: var(--transition);
  z-index: 95;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background: var(--primary-dark);
  transform: translateY(-3px);
}

@media (max-width: 768px) {
  .gre-alpha-btn { min-width: 30px; height: 30px; font-size: 0.75rem; }
  .gre-letter { min-width: 2rem; height: 2rem; }
  .gre-letter-title { display: none; }
  .back-to-top { bottom: 1.25rem; right: 1.25rem; width: 42px; height: 42px; }
}