/* ===== VARIABLES ===== */
:root {
  --primary-color: #3b82f6;
  --secondary-color: #e2e8f0;
  --card-bg: #ffffff;
  --chip-bg-light: #eef2ff;
  --chip-text: #1e40af;
  --correct-highlight: #dcfce7;
  --correct-border: #22c55e;
  --incorrect-highlight: #fee2e2;
  --incorrect-border: #ef4444;
  --drawer-bg: #ffffff;
  --drawer-shadow: rgba(0, 0, 0, 0.1);
  --text-primary: #0f172a;
  --text-secondary: #334155;
  --text-muted: #64748b;
  --surface: #f8fafc;
  --border-light: #e2e8f0;
}

/* ===== QUIZ CONTAINER ===== */
.quiz-container {
  max-width: 900px;
  margin: 2rem auto;
  padding: 0 1rem;
}

/* ── Header (Div1) ── */
.quiz-header {
  text-align: center;
  font-size: 2rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
  color: var(--text-primary);
}

/* ── Active filters bar (Div2) ── */
.active-filters {
  background: #f1f5f9;
  border-radius: 2rem;
  padding: 0.75rem 1.25rem;
  margin-bottom: 1.5rem;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
}
.active-filters span {
  font-weight: 500;
  font-size: 0.9rem;
}
.chips-container {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
}
.active-filter-chip {
  display: inline-flex;
  align-items: center;
  border-radius: 2rem;
  padding: 0.25rem 0.75rem;
  font-size: 0.85rem;
}
.filter-count-badge {
  background: var(--text-muted);
  color: white;
  border-radius: 999px;
  width: 1.8rem;
  height: 1.8rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 0.9rem;
  font-weight: 600;
  flex-shrink: 0;
}

/* ── Question cards (Div3) ── */
.quiz-questions {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

/* Card entrance animation for newly loaded cards */
@keyframes card-enter {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--secondary-color);
  border-radius: 1rem;
  padding: 1.5rem;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
  transition: box-shadow 0.2s ease;
  animation: card-enter 0.3s ease both;
}

/* Card glow after submit - blooms then settles into a permanent tint */
@keyframes glow-correct {
  0% {
    box-shadow: 0 0 0 4px rgba(34, 197, 94, 0.55);
  }
  100% {
    box-shadow: 0 0 0 2px var(--correct-border),
      0 4px 14px rgba(34, 197, 94, 0.12);
  }
}
@keyframes glow-incorrect {
  0% {
    box-shadow: 0 0 0 4px rgba(239, 68, 68, 0.55);
  }
  100% {
    box-shadow: 0 0 0 2px var(--incorrect-border),
      0 4px 14px rgba(239, 68, 68, 0.12);
  }
}

.card--correct {
  animation: glow-correct 0.4s ease forwards;
}
.card--incorrect {
  animation: glow-incorrect 0.4s ease forwards;
}

.question-text {
  font-weight: 700;
  font-size: 1.1rem;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
  line-height: 1.55;
}
.tags-container {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1rem;
}
.tag-chip {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  border-radius: 9999px;
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-primary);
}

/* ── Options ── */
.options {
  display: flex;
  flex-direction: column;
  margin-bottom: 1.25rem;
}

.option {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem;
  border-radius: 0.5rem;
  border-left: 4px solid transparent; /* reserved space - prevents layout shift on highlight */
  transition: background 0.15s ease;
  /* cursor: pointer; */
  cursor: default;
}

.option.correct-highlight {
  background-color: var(--correct-highlight);
  border-left-color: var(--correct-border);
}
.option.incorrect-highlight {
  background-color: var(--incorrect-highlight);
  border-left-color: var(--incorrect-border);
}
.option input[type="radio"] {
  width: 1.1rem;
  height: 1.1rem;
  accent-color: var(--primary-color);
  margin: 0;
  flex-shrink: 0;
  cursor: pointer;
}
.option input[type="radio"]:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}
.option label {
  font-size: 0.95rem;
  cursor: pointer;
  flex: 1;
  line-height: 1.5;
  color: var(--text-secondary);
}

/* ── Option icons (check / cross) ── */

/* Spring-in animation for first appearance */
@keyframes icon-spring {
  0% {
    transform: scale(0);
    opacity: 0;
  }
  55% {
    transform: scale(1.22);
    opacity: 1;
  }
  100% {
    transform: scale(1);
    opacity: 1;
  }
}

.option-icon {
  display: inline-flex;
  align-items: center;
  flex-shrink: 0;
  margin-left: auto;
  transform: scale(0);
  opacity: 0;
  animation: icon-spring 0.3s cubic-bezier(0.34, 1.56, 0.64, 1) forwards;
  font-size: 0.9rem; /* controls SVG size via em inheritance if needed */
}
.option-icon--correct {
  color: var(--correct-border);
}
.option-icon--incorrect {
  color: var(--incorrect-border);
}
/* Skip animation when icon is re-injected after a re-render (toggle/clear) */
.option-icon--instant {
  animation: none;
  transform: scale(1);
  opacity: 1;
}

/* ── Action buttons ── */
.action-buttons {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 1rem;
}
.btn-group-left,
.btn-group-right {
  display: flex;
  gap: 0.75rem;
}

button {
  background: none;
  border: none;
  font-size: 0.85rem;
  font-weight: 500;
  padding: 0.4rem 0.9rem;
  border-radius: 0.5rem;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease, opacity 0.15s ease;
}
.btn-secondary {
  background-color: #f1f5f9;
  color: var(--text-primary);
  border: 1px solid #cbd5e1;
}
.btn-secondary:hover:not(:disabled) {
  background-color: var(--secondary-color);
}
.btn-primary {
  background-color: var(--primary-color);
  color: white;
}
.btn-primary:hover:not(:disabled) {
  background-color: #2563eb;
}
button:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}
button:focus-visible {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

/* ── Answer & explanation reveal ── */

/* Slide-in animation for the reveal container */
@keyframes reveal-slide {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.answer-explanation-container:not(:empty) {
  animation: reveal-slide 0.25s ease both;
}

/* Applied via JS to trigger animation on submit */
.reveal-animate {
  animation: reveal-slide 0.25s ease both;
}

.answer-section,
.explanation-section {
  margin-top: 0.75rem;
  padding: 0.75rem 1rem;
  background-color: var(--surface);
  border-radius: 0.5rem;
  border-left: 4px solid var(--primary-color);
  font-size: 0.9rem;
}
.answer-section strong,
.explanation-section strong {
  font-weight: 600;
  color: var(--text-primary);
}
.explanation-section {
  color: var(--text-secondary);
  line-height: 1.65;
}
.explanation-section code {
  background: #eff1f3;
  padding: 1px 5px;
  border-radius: 4px;
  font-size: 0.82rem;
  font-family: ui-monospace, monospace;
  color: #c7254e;
}
.explanation-section p {
  margin: 0 0 0.4rem;
}
.explanation-section p:last-child {
  margin-bottom: 0;
}

.hidden {
  display: none;
}

/* ── Load more ── */
.load-more-container {
  text-align: center;
  margin: 2rem 0 1rem;
}
.load-more-btn {
  background-color: var(--primary-color);
  color: white;
  padding: 0.75rem 2rem;
  font-size: 1rem;
  border-radius: 2rem;
  transition: background 0.15s ease, opacity 0.15s ease;
}
.load-more-btn:hover:not(:disabled) {
  background-color: #2563eb;
}
.load-more-btn:disabled {
  background-color: #94a3b8;
  cursor: not-allowed;
}

/* ── Floating buttons ── */
.floating-btn {
  position: fixed;
  bottom: 1.5rem;
  width: 3rem;
  height: 3rem;
  border-radius: 9999px;
  background-color: var(--primary-color);
  color: white;
  font-size: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
  border: none;
  cursor: pointer;
  transition: background 0.2s ease, transform 0.2s ease, opacity 0.2s ease;
  z-index: 100;
}
.floating-btn:hover {
  background-color: #2563eb;
  transform: scale(1.07);
}
.floating-btn:focus-visible {
  outline: 2px solid var(--primary-color);
  outline-offset: 3px;
}
.back-to-top {
  right: 1.5rem;
}
.floating-btn.hidden {
  opacity: 0;
  pointer-events: none;
  transform: translateY(6px);
}
.floating-btn:not(.hidden) {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}
.menu-icon {
  right: 5rem;
}

/* ── Drawer overlay ── */
.drawer-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.25);
  z-index: 199;
  backdrop-filter: blur(1px);
  cursor: pointer;
}
[hidden] {
  display: none;
}

/* ── Drawer ── */
.drawer {
  position: fixed;
  top: 0;
  right: -400px;
  width: 350px;
  max-width: 85vw;
  height: 100%;
  background-color: var(--drawer-bg);
  box-shadow: -2px 0 16px var(--drawer-shadow);
  transition: right 0.3s ease;
  z-index: 200;
  display: flex;
  flex-direction: column;
}
.drawer.open {
  right: 0;
}
.drawer-content {
  display: flex;
  flex-direction: column;
  height: 100%;
  padding: 1.25rem 1rem 1rem;
}
.tag-list-container {
  flex: 1;
  overflow-y: auto;
  margin-bottom: 1rem;
}
.tag-list-container h3 {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.75rem;
}

/* Drawer tag chips - flex wrap layout (was incorrectly set via inline JS) */
.tag-checkboxes {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

/* Each tag in the drawer is a chip-style label */
.tag-checkbox-item {
  cursor: pointer;
  border-radius: 9999px;
  display: inline-flex;
  align-items: center;
}
.tag-checkbox-item input[type="checkbox"] {
  position: absolute;
  opacity: 0;
  pointer-events: none;
  width: 0;
  height: 0;
}
.tag-checkbox-item .tag-chip {
  opacity: 0.7;
  font-weight: 400;
  transition: opacity 0.15s, filter 0.15s;
  cursor: pointer;
}
.tag-checkbox-item:hover .tag-chip {
  opacity: 0.9;
}
.tag-checkbox-item.selected .tag-chip {
  opacity: 1;
  font-weight: 700;
  filter: brightness(0.82);
}
.tag-checkbox-item:focus-within {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
  border-radius: 9999px;
}

.drawer-actions {
  display: flex;
  gap: 0.75rem;
  border-top: 1px solid var(--border-light);
  padding-top: 1rem;
  flex-shrink: 0;
}
.drawer-actions button {
  flex: 1;
  padding: 0.55rem 0.75rem;
}

/* ── Responsive ── */
@media (max-width: 640px) {
  .quiz-container {
    padding: 0 0.75rem;
  }
  .action-buttons {
    flex-direction: column;
    align-items: stretch;
  }
  .btn-group-left,
  .btn-group-right {
    justify-content: space-between;
  }
  .drawer {
    width: 100vw;
    max-width: 100vw;
  }
}