:root {
  --bg: #f6f8fb;
  --surface: #ffffff;
  --text: #222;
  --choice-text: #111827;
  --muted: #6b7280;
  --primary: #2563eb;
  --primary-dark: #1e3a8a;
  --danger: #dc2626;
  --danger-soft: rgba(220, 38, 38, 0.1);
  --border: #d1d5db;
  --success: #16a34a;
  --success-soft: rgba(22, 163, 74, 0.12);
}

.dark-mode {
  --bg: #111827;
  --surface: #1f2937;
  --text: #f9fafb;
  --choice-text: #f9fafb;
  --muted: #9ca3af;
  --primary: #60a5fa;
  --primary-dark: #2563eb;
  --danger: #f87171;
  --danger-soft: rgba(248, 113, 113, 0.18);
  --border: #374151;
  --success: #34d399;
  --success-soft: rgba(52, 211, 153, 0.2);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Inter", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

a {
  color: inherit;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
}

.app-header .brand a {
  font-weight: 700;
  font-size: 1.25rem;
}

.app-header nav {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.dark-toggle {
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.25rem 0.75rem;
  cursor: pointer;
}

.app-main {
  padding: 2rem;
  max-width: 1100px;
  margin: 0 auto;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  box-shadow: 0 20px 40px rgba(15, 23, 42, 0.08);
}

.card.narrow {
  max-width: 420px;
  margin: 3rem auto;
}

.page-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.5rem;
  gap: 1rem;
}

.page-header .actions {
  display: flex;
  gap: 0.75rem;
}

.grid.two {
  display: grid;
  gap: 1.5rem;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
}

.form-grid {
  display: grid;
  gap: 0.75rem;
}

.form-toggle {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-top: 0.75rem;
  font-size: 0.95rem;
  color: var(--muted);
}

.form-toggle input[type="checkbox"] {
  margin: 0;
}

.form-grid input,
.form-grid textarea {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.75rem;
  font-size: 1rem;
  background: transparent;
  color: var(--text);
}

.form-error {
  color: var(--danger);
  margin: 0;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  padding: 0.5rem 1.25rem;
  border: 1px solid var(--border);
  cursor: pointer;
  background: transparent;
  color: var(--text);
  font-weight: 600;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 10px 20px rgba(15, 23, 42, 0.08);
}

.btn.primary {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

.btn.primary:hover {
  background: var(--primary-dark);
}

.btn.danger {
  border-color: var(--danger);
  color: var(--danger);
}

.btn.subtle {
  border: none;
  box-shadow: none;
  padding: 0.25rem 0.5rem;
}

.flash-container {
  display: grid;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.flash {
  padding: 0.75rem 1rem;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: rgba(37, 99, 235, 0.08);
}

.flash-info { background: rgba(59, 130, 246, 0.12); }
.flash-success { background: rgba(16, 185, 129, 0.12); }
.flash-danger { background: rgba(220, 38, 38, 0.12); }

.list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1rem;
}

.list li {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1rem;
}

.list li h3 {
  margin: 0 0 0.25rem;
}

.muted {
  color: var(--muted);
  margin: 0;
}

.inline-form {
  display: inline;
}

.question-list {
  display: grid;
  gap: 1rem;
}

.question-item {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1rem;
}

.question-item header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}


.question-row {
  display: flex;
  justify-content: space-between;
  align-items: stretch;
  gap: 1rem;
}

.question-actions {
  display: flex;
  gap: 0.5rem;
}

.question-row__main {
  flex: 1;
}

.question-row__controls {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 0.75rem;
  min-width: 200px;
}

.timer-override {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.25rem;
  font-size: 0.95rem;
}

.timer-override input {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.4rem 0.6rem;
  width: 120px;
  background: transparent;
  color: var(--text);
}

.timer-override small {
  font-size: 0.8rem;
}

.live-actions {
  margin-top: 1rem;
}

.question-form {
  display: grid;
  gap: 0.75rem;
  margin-top: 1rem;
}

.question-form textarea,
.question-form input[type="number"] {
  width: 100%;
  border-radius: 10px;
  border: 1px solid var(--border);
  padding: 0.5rem;
  background: transparent;
  color: var(--text);
}

.choice-editor {
  display: grid;
  gap: 0.5rem;
}

.choice-row {
  display: grid;
  grid-template-columns: 1fr auto auto;
  gap: 0.5rem;
  align-items: center;
}

.choice-row input[type="text"] {
  width: 100%;
  border-radius: 8px;
  border: 1px solid var(--border);
  padding: 0.5rem;
  background: transparent;
  color: var(--text);
}

.checkbox {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.join-card {
  text-align: center;
}

.join-card input {
  text-transform: uppercase;
  letter-spacing: 0.2rem;
  text-align: center;
}

.waiting-card {
  text-align: center;
}

.waiting-card .code {
  font-size: 1.25rem;
}

.quiz-card {
  max-width: 720px;
  margin: 0 auto;
}

.question-panel {
  border-bottom: 1px solid var(--border);
  margin-bottom: 1rem;
}

.question-meta {
  display: flex;
  justify-content: space-between;
  color: var(--muted);
  font-size: 0.95rem;
}

.student-info {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  margin-bottom: 1rem;
  font-size: 0.95rem;
  color: var(--muted);
}

.student-info__name strong {
  color: var(--text);
}

.student-info__stats {
  display: flex;
  gap: 0.75rem;
}

.student-info__stats span {
  color: var(--text);
  font-weight: 600;
}

.choices {
  display: grid;
  gap: 0.75rem;
}

.quiz-card [data-submit-choices] {
  display: block;
  margin: 1.5rem auto 0;
}

.choice-button {
  padding: 0.75rem;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: transparent;
  cursor: pointer;
  text-align: left;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  transition: border-color 0.2s ease, box-shadow 0.2s ease, background-color 0.2s ease,
    color 0.2s ease;
  color: var(--choice-text);
}

.choice-button .choice-label {
  flex: 1;
  font-weight: 600;
  color: var(--choice-text);
}

.choice-button.correct .choice-label,
.choice-button.correct .choice-result,
.choice-button.incorrect .choice-label,
.choice-button.incorrect .choice-result {
  color: inherit;
}

.choice-button.selected {
  border-color: var(--primary);
  box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.25);
}

.choice-button.locked {
  cursor: default;
  opacity: 1;
  background: rgba(37, 99, 235, 0.05);
}

.dark-mode .choice-button.locked {
  background: rgba(96, 165, 250, 0.18);
}

.choice-button.revealed:not(.correct) {
  opacity: 0.85;
}

.choice-button.correct {
  border-color: var(--success);
  box-shadow: 0 0 0 2px rgba(22, 163, 74, 0.2);
  background: var(--success-soft);
  color: var(--success);
}

.dark-mode .choice-button.correct {
  box-shadow: 0 0 0 2px rgba(52, 211, 153, 0.25);
  color: var(--success);
}

.choice-button.incorrect {
  border-color: var(--danger);
  box-shadow: 0 0 0 2px rgba(220, 38, 38, 0.15);
  background: var(--danger-soft);
  color: var(--danger);
  opacity: 1;
}

.dark-mode .choice-button.incorrect {
  box-shadow: 0 0 0 2px rgba(248, 113, 113, 0.25);
  color: var(--danger);
}

.choice-result {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.9rem;
  color: var(--muted);
}

.choice-result[hidden] {
  display: none;
}

.choice-icon {
  color: var(--success);
  font-size: 1.1rem;
  line-height: 1;
}

.status {
  margin-top: 1rem;
  color: var(--muted);
}

.live-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
}

.live-header .qr {
  width: 120px;
  height: 120px;
}

.live-question ul {
  list-style: none;
  padding: 0;
  margin: 0.5rem 0;
}

.live-question li {
  display: flex;
  justify-content: space-between;
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--border);
}

.live-question li.correct {
  color: var(--primary);
  font-weight: 600;
}

details.asked-questions {
  margin-top: 2rem;
}

details.asked-questions summary {
  cursor: pointer;
  font-weight: 600;
  list-style: none;
}

details.asked-questions[hidden] {
  display: none;
}

details.asked-questions .question-list {
  margin-top: 1rem;
}

.scoreboard table {
  width: 100%;
  border-collapse: collapse;
}

.scoreboard th,
.scoreboard td {
  text-align: left;
  padding: 0.5rem;
  border-bottom: 1px solid var(--border);
}

.scoreboard [data-score-sort] {
  background: none;
  border: none;
  padding: 0;
  font: inherit;
  color: inherit;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
}

.scoreboard [data-score-sort]:focus {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}

.scoreboard [data-score-sort].is-active {
  color: var(--primary);
  font-weight: 600;
}

.scoreboard [data-score-sort][data-sort-direction="asc"]::after {
  content: "▲";
  font-size: 0.75em;
  color: var(--muted);
}

.scoreboard [data-score-sort][data-sort-direction="desc"]::after {
  content: "▼";
  font-size: 0.75em;
  color: var(--muted);
}

.grid-table {
  margin-top: 1rem;
  overflow-x: auto;
}

.grid-table table {
  width: 100%;
  border-collapse: collapse;
}

.grid-table th,
.grid-table td {
  padding: 0.25rem 0.5rem;
  text-align: center;
  border-bottom: 1px solid var(--border);
}

.grid-table td.status-correct {
  color: var(--success);
  font-weight: 600;
}

.grid-table td.status-incorrect {
  color: var(--danger);
  font-weight: 600;
}

.grid-table td.status-pending {
  color: var(--muted);
  font-style: italic;
}

.grid-table td.status-unanswered {
  color: var(--muted);
}

.display-screen {
  background: var(--surface);
}

.display-main {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
  text-align: center;
  padding: 3rem 1rem;
}

.display-code {
  font-size: clamp(4rem, 8vw, 6rem);
  letter-spacing: 0.6rem;
  font-weight: 700;
}

.display-url {
  font-size: 1.1rem;
  word-break: break-word;
  max-width: 640px;
}

.display-qr {
  width: min(40vw, 220px);
  height: auto;
  border: 10px solid var(--surface);
  border-radius: 16px;
  box-shadow: 0 20px 40px rgba(15, 23, 42, 0.15);
}

.history-table {
  width: 100%;
  border-collapse: collapse;
}

.history-table th,
.history-table td {
  text-align: left;
  padding: 0.75rem;
  border-bottom: 1px solid var(--border);
}

.history-table .actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.history-table .actions form {
  margin: 0;
}

@media (max-width: 768px) {
  .app-main {
    padding: 1rem;
  }

  .page-header {
    flex-direction: column;
    align-items: flex-start;
  }

  .question-item header,
  .live-header {
    flex-direction: column;
    align-items: flex-start;
  }

  .choice-row {
    grid-template-columns: 1fr;
  }
}