/* ===================================================
   CÁLCULO DIFERENCIAL — Quiz / Activity Page Styles
   =================================================== */

/* --- Quiz Page Layout --- */
.quiz-wrapper {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.quiz-wrapper::before {
  content: '';
  position: fixed;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--accent-teal), var(--brand-from), var(--brand-to));
  z-index: 100;
}

/* --- Quiz Header --- */
.quiz-header {
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-subtle);
  padding: var(--space-md) var(--space-xl);
  position: sticky;
  top: 0;
  z-index: 50;
}

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

.quiz-title-group {}
.quiz-title-group h2 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
}
.quiz-title-group p {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin: 0;
}

.quiz-status {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.quiz-counter {
  font-size: 0.8rem;
  color: var(--text-secondary);
  font-weight: 500;
}

/* Score pill */
.score-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border-normal);
  border-radius: var(--radius-full);
  padding: 0.3rem 0.75rem;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-primary);
  transition: all var(--duration-normal) var(--ease-out);
}

.score-pill.updated {
  border-color: var(--accent-green);
  color: var(--accent-green);
  box-shadow: 0 0 12px rgba(74, 222, 128, 0.25);
}

/* --- Progress Tracker --- */
.quiz-progress {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: var(--space-md) var(--space-xl);
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.progress-dots {
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
}

.progress-dot {
  width: 28px; height: 28px;
  border-radius: var(--radius-sm);
  border: 2px solid var(--border-normal);
  background: var(--bg-card);
  display: flex; align-items: center; justify-content: center;
  font-size: 0.65rem;
  font-weight: 700;
  color: var(--text-muted);
  cursor: pointer;
  transition: all var(--duration-fast) var(--ease-out);
}

.progress-dot.active {
  border-color: var(--brand-from);
  background: var(--brand-glow);
  color: var(--brand-to);
  box-shadow: 0 0 10px rgba(108,99,255,0.3);
}

.progress-dot.correct {
  border-color: var(--accent-green);
  background: rgba(74, 222, 128, 0.15);
  color: var(--accent-green);
}

.progress-dot.incorrect {
  border-color: var(--accent-rose);
  background: rgba(244, 63, 94, 0.12);
  color: var(--accent-rose);
}

.progress-dot.skipped {
  border-color: var(--accent-amber);
  background: rgba(251, 191, 36, 0.1);
  color: var(--accent-amber);
}

/* --- Quiz Main --- */
.quiz-main {
  flex: 1;
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: var(--space-xl);
  width: 100%;
}

/* --- Question Card --- */
.question-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  padding: var(--space-2xl);
  margin-bottom: var(--space-xl);
  animation: fadeInUp 0.35s var(--ease-out) both;
  position: relative;
  overflow: hidden;
}

.question-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0; height: 1px;
  background: linear-gradient(90deg, transparent, var(--brand-from), transparent);
  opacity: 0.5;
}

.question-number-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background: var(--brand-glow);
  border: 1px solid rgba(108,99,255,0.3);
  border-radius: var(--radius-full);
  padding: 0.25rem 0.75rem;
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--brand-to);
  letter-spacing: 0.05em;
  text-transform: uppercase;
  margin-bottom: var(--space-lg);
}

.question-text {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.5;
  margin-bottom: var(--space-lg);
}

.question-hint {
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-bottom: var(--space-xl);
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

/* --- Answer Options --- */
.options-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.option-item {
  animation: fadeInUp 0.3s var(--ease-out) both;
}
.option-item:nth-child(1) { animation-delay: 0.05s; }
.option-item:nth-child(2) { animation-delay: 0.10s; }
.option-item:nth-child(3) { animation-delay: 0.15s; }
.option-item:nth-child(4) { animation-delay: 0.20s; }

.option-btn {
  width: 100%;
  display: flex;
  align-items: center;
  gap: var(--space-md);
  background: var(--bg-surface);
  border: 2px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: var(--space-md) var(--space-lg);
  cursor: pointer;
  text-align: left;
  transition: all var(--duration-normal) var(--ease-out);
  font-family: var(--font-sans);
  font-size: 0.95rem;
  color: var(--text-secondary);
  position: relative;
  overflow: hidden;
}

.option-btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--brand-from), var(--brand-to));
  opacity: 0;
  transition: opacity var(--duration-normal) var(--ease-out);
}

.option-btn:hover:not(:disabled) {
  border-color: var(--brand-from);
  color: var(--text-primary);
  transform: translateX(4px);
  background: rgba(108, 99, 255, 0.06);
}

.option-btn:disabled {
  cursor: default;
}

.option-letter {
  width: 32px; height: 32px;
  border-radius: var(--radius-sm);
  background: var(--bg-elevated);
  border: 1px solid var(--border-normal);
  display: flex; align-items: center; justify-content: center;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--text-muted);
  flex-shrink: 0;
  transition: all var(--duration-normal) var(--ease-out);
  position: relative; z-index: 1;
}

.option-btn:hover:not(:disabled) .option-letter {
  background: var(--brand-glow);
  border-color: var(--brand-from);
  color: var(--brand-to);
}

.option-text {
  position: relative; z-index: 1;
  flex: 1;
}

.option-icon {
  flex-shrink: 0;
  font-size: 1.1rem;
  position: relative; z-index: 1;
  opacity: 0;
  transition: opacity var(--duration-fast) var(--ease-out);
}

/* --- Option States --- */
.option-btn.selected {
  border-color: var(--brand-from);
  background: rgba(108, 99, 255, 0.08);
  color: var(--text-primary);
}
.option-btn.selected .option-letter {
  background: var(--brand-glow);
  border-color: var(--brand-from);
  color: var(--brand-to);
}

.option-btn.correct {
  border-color: var(--accent-green);
  background: rgba(74, 222, 128, 0.08);
  color: var(--text-primary);
}
.option-btn.correct .option-letter {
  background: rgba(74, 222, 128, 0.15);
  border-color: var(--accent-green);
  color: var(--accent-green);
}
.option-btn.correct .option-icon { opacity: 1; }

.option-btn.incorrect {
  border-color: var(--accent-rose);
  background: rgba(244, 63, 94, 0.07);
  color: var(--text-secondary);
  transform: none;
}
.option-btn.incorrect .option-letter {
  background: rgba(244, 63, 94, 0.12);
  border-color: var(--accent-rose);
  color: var(--accent-rose);
}
.option-btn.incorrect .option-icon { opacity: 1; }

.option-btn.reveal-correct {
  border-color: var(--accent-green);
  background: rgba(74, 222, 128, 0.05);
}
.option-btn.reveal-correct .option-letter {
  border-color: var(--accent-green);
  color: var(--accent-green);
}

/* --- Feedback Panel --- */
.feedback-panel {
  border-radius: var(--radius-lg);
  padding: var(--space-lg) var(--space-xl);
  margin-top: var(--space-xl);
  animation: fadeInUp 0.3s var(--ease-out) both;
  display: flex;
  gap: var(--space-md);
  align-items: flex-start;
}

.feedback-panel.correct-feedback {
  background: rgba(74, 222, 128, 0.08);
  border: 1px solid rgba(74, 222, 128, 0.25);
}

.feedback-panel.incorrect-feedback {
  background: rgba(244, 63, 94, 0.07);
  border: 1px solid rgba(244, 63, 94, 0.2);
}

.feedback-icon {
  font-size: 1.5rem;
  flex-shrink: 0;
  margin-top: 2px;
}

.feedback-content {}
.feedback-title {
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
}
.feedback-text {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin: 0;
}
.feedback-text .katex { font-size: 0.95em; }

/* --- Action Bar --- */
.action-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  margin-top: var(--space-xl);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--border-subtle);
}

/* --- Results Screen --- */
.results-screen {
  text-align: center;
  padding: var(--space-3xl) var(--space-xl);
  animation: fadeInUp 0.5s var(--ease-out) both;
}

.results-emoji {
  font-size: 4rem;
  display: block;
  margin-bottom: var(--space-md);
  animation: float 3s ease-in-out infinite;
}

.results-title {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: var(--space-sm);
}

.results-subtitle {
  color: var(--text-secondary);
  margin-bottom: var(--space-2xl);
}

.results-score-ring {
  position: relative;
  width: 160px; height: 160px;
  margin: 0 auto var(--space-2xl);
}

.results-score-ring svg {
  transform: rotate(-90deg);
  width: 160px; height: 160px;
}

.results-score-ring .ring-bg {
  fill: none;
  stroke: var(--bg-elevated);
  stroke-width: 10;
}

.results-score-ring .ring-fill {
  fill: none;
  stroke-width: 10;
  stroke-linecap: round;
  stroke-dasharray: 408;
  stroke-dashoffset: 408;
  transition: stroke-dashoffset 1.2s var(--ease-out);
}

.results-score-ring .ring-text {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.results-score-ring .ring-percent {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-primary);
}

.results-score-ring .ring-label {
  font-size: 0.72rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.results-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-md);
  max-width: 480px;
  margin: 0 auto var(--space-2xl);
}

.result-stat {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
}

.result-stat-num {
  font-size: 1.8rem;
  font-weight: 700;
  margin-bottom: 0.2rem;
}

.result-stat-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.result-stat.correct  .result-stat-num { color: var(--accent-green); }
.result-stat.incorrect .result-stat-num { color: var(--accent-rose); }
.result-stat.score     .result-stat-num { color: var(--brand-to); }

.results-actions {
  display: flex;
  gap: var(--space-md);
  justify-content: center;
  flex-wrap: wrap;
}

/* --- Input answer type --- */
.answer-input-wrapper {
  display: flex;
  gap: var(--space-sm);
  margin: var(--space-lg) 0;
  align-items: center;
}

.answer-input {
  flex: 1;
  background: var(--bg-surface);
  border: 2px solid var(--border-normal);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 1rem;
  padding: 0.75rem 1rem;
  outline: none;
  transition: border-color var(--duration-normal) var(--ease-out);
}

.answer-input:focus {
  border-color: var(--brand-from);
  box-shadow: 0 0 0 3px var(--brand-glow);
}

.answer-input.correct  { border-color: var(--accent-green); }
.answer-input.incorrect { border-color: var(--accent-rose); }

/* --- Responsive --- */
@media (max-width: 640px) {
  .quiz-main      { padding: var(--space-md); }
  .question-card  { padding: var(--space-lg); }
  .results-stats  { grid-template-columns: 1fr 1fr; }
  .quiz-header-inner { flex-wrap: wrap; }
  .quiz-progress  { padding: var(--space-sm) var(--space-md); }
}