/* ============================================================================
 * Difficulty Filter & Badge Styles
 * Used on flash card and exam pages to filter and color-code by difficulty.
 * ============================================================================ */

/* ---------------------------------------------------------------------------
 * Difficulty Filter Bar
 * --------------------------------------------------------------------------- */

.difficulty-filter-bar {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1rem;
  margin-bottom: 1rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-soft);
  border-radius: 0.75rem;
  flex-wrap: wrap;
}

.difficulty-filter-bar .filter-label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-muted);
  margin-right: 0.25rem;
  white-space: nowrap;
}

.difficulty-filter-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.4rem 0.85rem;
  font-size: 0.82rem;
  font-weight: 500;
  border: 1.5px solid var(--border-soft);
  border-radius: 2rem;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  transition: all 0.2s ease;
  user-select: none;
}

.difficulty-filter-btn:hover {
  border-color: var(--text-muted);
  color: var(--text-main);
}

.difficulty-filter-btn.active.beginner {
  background: var(--diff-beginner-soft);
  border-color: var(--diff-beginner);
  color: var(--diff-beginner);
}

.difficulty-filter-btn.active.intermediate {
  background: var(--diff-intermediate-soft);
  border-color: var(--diff-intermediate);
  color: var(--diff-intermediate);
}

.difficulty-filter-btn.active.advanced {
  background: var(--diff-advanced-soft);
  border-color: var(--diff-advanced);
  color: var(--diff-advanced);
}

.difficulty-filter-btn .filter-count {
  font-size: 0.75rem;
  opacity: 0.8;
}

/* ---------------------------------------------------------------------------
 * Difficulty Badge (on cards / questions)
 * --------------------------------------------------------------------------- */

.difficulty-badge {
  display: inline-block;
  padding: 0.15rem 0.55rem;
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  border-radius: 1rem;
  line-height: 1.4;
  vertical-align: middle;
}

.difficulty-badge.beginner {
  background: var(--diff-beginner-soft);
  color: var(--diff-beginner);
  border: 1px solid var(--diff-beginner);
}

.difficulty-badge.intermediate {
  background: var(--diff-intermediate-soft);
  color: var(--diff-intermediate);
  border: 1px solid var(--diff-intermediate);
}

.difficulty-badge.advanced {
  background: var(--diff-advanced-soft);
  color: var(--diff-advanced);
  border: 1px solid var(--diff-advanced);
}

/* ---------------------------------------------------------------------------
 * Flash Card Difficulty Border
 * --------------------------------------------------------------------------- */

.flash-card-container .flash-card.difficulty-beginner {
  border-left: 3px solid var(--diff-beginner);
}

.flash-card-container .flash-card.difficulty-intermediate {
  border-left: 3px solid var(--diff-intermediate);
}

.flash-card-container .flash-card.difficulty-advanced {
  border-left: 3px solid var(--diff-advanced);
}

/* Badge placement inside flash card */
.flash-card .card-difficulty-badge {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  z-index: 2;
}

/* Ensure flash card has relative positioning for badge */
.flash-card {
  position: relative;
}

/* ---------------------------------------------------------------------------
 * Exam Difficulty Selector (start screen)
 * --------------------------------------------------------------------------- */

.exam-difficulty-selector {
  margin-top: 1rem;
}

.exam-difficulty-selector label {
  display: block;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--text-main);
}

.exam-difficulty-selector select {
  width: 100%;
  padding: 0.5rem 0.75rem;
  font-size: 0.95rem;
  border: 1px solid var(--border-soft);
  border-radius: 0.5rem;
  background: var(--bg-primary);
  color: var(--text-main);
  cursor: pointer;
}

.exam-difficulty-selector select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.25);
}

/* Difficulty badge in exam question header */
.exam-question-header .difficulty-badge {
  margin-left: 0.75rem;
}

/* Difficulty badge in exam navigation sidebar */
.exam-nav-btn.diff-beginner {
  border-bottom: 2px solid var(--diff-beginner);
}

.exam-nav-btn.diff-intermediate {
  border-bottom: 2px solid var(--diff-intermediate);
}

.exam-nav-btn.diff-advanced {
  border-bottom: 2px solid var(--diff-advanced);
}

/* Review item difficulty */
.review-item-header .difficulty-badge {
  margin-left: 0.5rem;
}