/* Panel de materia en study home */
.materia-card {
  background: var(--surface);
  border: 1px solid var(--line);
  overflow: hidden;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.materia-card:hover {
  border-color: var(--red);
  box-shadow: 0 0 0 1px var(--red-glow), 0 0 20px rgba(255,42,42,0.08);
}

.materia-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 20px;
  cursor: pointer;
  user-select: none;
}

.materia-card-name {
  font-size: 1rem;
  font-weight: 600;
}

.materia-card-count {
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

.materia-card-chevron {
  color: var(--color-text-muted);
  transition: transform var(--transition-fast);
  font-style: normal;
}

.materia-card.open .materia-card-chevron {
  transform: rotate(180deg);
}

.materia-card-body {
  display: none;
  padding: 0 16px 16px;
  flex-direction: column;
  gap: 6px;
}

.materia-card.open .materia-card-body {
  display: flex;
}

/* Fase de contenido en sesión de estudio */
.study-phase {
  animation: fadeInUp 0.4s ease;
}

.study-content-block {
  margin-bottom: 24px;
}

.study-content-title {
  font-size: 1.3rem;
  font-weight: 600;
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--color-border);
}

.competencia-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  background: var(--color-primary-dim);
  border: 1px solid var(--color-primary-glow);
  border-radius: 20px;
  font-size: 0.75rem;
  color: var(--color-primary-light);
  margin-bottom: 16px;
  margin-right: 6px;
}

.icfes-tip-box {
  background: var(--color-surface-2);
  border-left: 3px solid var(--color-primary);
  padding: 14px 18px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin-top: 20px;
  font-size: 0.88rem;
}

.icfes-tip-box strong {
  display: block;
  color: var(--color-primary);
  margin-bottom: 4px;
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* Diagrama SVG */
.diagram-block {
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 24px;
  text-align: center;
  margin: 20px 0;
}

.diagram-block svg {
  max-width: 100%;
  height: auto;
}

.diagram-caption {
  font-size: 0.82rem;
  color: var(--color-text-muted);
  margin-top: 12px;
}

/* Actividad de comprensión */
.activity-block {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 24px;
  margin: 20px 0;
}

.activity-tag {
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--color-primary);
  margin-bottom: 12px;
}

.activity-instruccion {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  margin-bottom: 12px;
  font-style: italic;
}

.activity-pregunta {
  font-size: 1rem;
  font-weight: 500;
  margin-bottom: 16px;
  line-height: 1.6;
}

.activity-options {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.activity-option {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 12px 16px;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
  text-align: left;
  width: 100%;
}

.activity-option:hover {
  border-color: var(--color-primary);
  background: var(--color-surface-3);
}

.activity-option.selected {
  border-color: var(--color-primary);
  background: var(--color-primary-dim);
}

.activity-option.correct {
  border-color: var(--color-success);
  background: rgba(34, 197, 94, 0.1);
}

.activity-option.wrong {
  border-color: var(--color-error);
  background: rgba(239, 68, 68, 0.1);
}

.activity-option.reveal-correct {
  border-color: var(--color-success);
  background: rgba(34, 197, 94, 0.05);
}

.option-letter {
  font-weight: 700;
  color: var(--color-primary);
  min-width: 20px;
}

.activity-option.correct .option-letter { color: var(--color-success); }
.activity-option.wrong .option-letter { color: var(--color-error); }

.activity-explanation {
  margin-top: 16px;
  padding: 14px;
  background: var(--color-surface-2);
  border-radius: var(--radius-sm);
  border-left: 3px solid var(--color-success);
  font-size: 0.9rem;
  animation: fadeInUp 0.3s ease;
}

/* Actividad de ejercicio paso a paso */
.exercise-block {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 24px;
  margin: 20px 0;
}

.exercise-formula {
  background: var(--color-surface-2);
  border-radius: var(--radius-sm);
  padding: 16px;
  font-size: 1.05rem;
  font-weight: 500;
  text-align: center;
  margin: 12px 0 20px;
  border-left: 3px solid var(--color-primary);
}

.exercise-steps {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.exercise-step {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  opacity: 0;
  transform: translateY(8px);
  transition: all 0.3s ease;
}

.exercise-step.revealed {
  opacity: 1;
  transform: translateY(0);
}

.step-number {
  min-width: 28px;
  height: 28px;
  background: var(--color-primary-dim);
  border: 1px solid var(--color-primary-glow);
  color: var(--color-primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.75rem;
  font-weight: 700;
  flex-shrink: 0;
}

.step-text {
  font-size: 0.9rem;
  padding-top: 4px;
}

.exercise-result {
  margin-top: 16px;
  padding: 12px 16px;
  background: rgba(34, 197, 94, 0.1);
  border-radius: var(--radius-sm);
  border: 1px solid rgba(34, 197, 94, 0.3);
  font-size: 0.95rem;
  font-weight: 600;
  text-align: center;
  display: none;
}

/* Conceptos clave y trampas */
.key-concepts {
  background: var(--color-surface-2);
  border-radius: var(--radius-md);
  padding: 20px;
  margin-top: 24px;
}

.key-concepts h4 {
  margin-bottom: 12px;
  color: var(--color-primary);
}

.key-concepts ul {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.key-concepts li {
  background: var(--color-surface-3);
  border: 1px solid var(--color-border);
  border-radius: 20px;
  padding: 4px 14px;
  font-size: 0.82rem;
}

.trampas-list li {
  padding: 8px 0;
  padding-left: 20px;
  position: relative;
  font-size: 0.88rem;
  color: var(--color-text-muted);
  border-bottom: 1px solid var(--color-border);
}

.trampas-list li::before {
  content: '⚠';
  position: absolute;
  left: 0;
  color: var(--color-warning);
}

/* Pie de sesión - botones de navegación */
.session-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 0;
  margin-top: 32px;
  border-top: 1px solid var(--color-border);
}

/* Pantalla de finalización de sesión de estudio */
.study-complete {
  text-align: center;
  padding: 48px 24px;
}

.study-complete-icon {
  font-size: 4rem;
  margin-bottom: 16px;
}

@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 768px) {
  .activity-block,
  .exercise-block,
  .diagram-block {
    padding: 16px;
  }

  .activity-options {
    gap: 6px;
  }

  .activity-option {
    padding: 10px 12px;
  }
}