:root {
  --bg: #f8fafc;
  --bg-elevated: #ffffff;
  --text: #0f172a;
  --text-muted: #475569;
  --border: #e2e8f0;
  --accent: #0b3d91;
  --accent-contrast: #ffffff;
  --success: #16a34a;
  --danger: #dc2626;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

:root[data-theme="dark"] {
  --bg: #0f172a;
  --bg-elevated: #1e293b;
  --text: #f1f5f9;
  --text-muted: #94a3b8;
  --border: #334155;
  --accent: #60a5fa;
  --accent-contrast: #0f172a;
  --success: #16a34a;
  --danger: #dc2626;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.4);
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  -webkit-text-size-adjust: 100%;
}

.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.25rem;
  background: var(--bg-elevated);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow);
}

.app-title {
  font-size: 1.1rem;
  font-weight: 600;
  margin: 0;
}

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 3.5rem;
  height: 2.5rem;
  padding: 0 0.75rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--bg);
  color: var(--text);
  cursor: pointer;
  font-size: 0.85rem;
  font-weight: 600;
  transition: background 0.15s ease;
}

.theme-toggle:hover {
  background: var(--border);
}

.theme-toggle:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.app-main {
  padding: 1.5rem 1.25rem;
  max-width: 720px;
  margin: 0 auto;
}

.app-footer {
  padding: 1.25rem;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.8rem;
}

.app-footer p {
  margin: 0;
}

.app-footer a {
  color: var(--text-muted);
  text-decoration: underline;
}

#footer-version {
  margin-top: 0.25rem;
  font-size: 0.75rem;
}

.about-text {
  margin: 0 0 1rem;
  color: var(--text);
  line-height: 1.5;
  font-size: 0.9rem;
}

.about-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.5rem;
  margin-top: 0.5rem;
}

@media (prefers-reduced-motion: reduce) {
  * {
    transition: none !important;
  }
}

.screen {
  margin-bottom: 2rem;
}

.screen-title {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 0 0 0.25rem;
}

.screen-sub {
  color: var(--text-muted);
  margin: 0 0 1.25rem;
}

.mode-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.75rem;
}

.mode-card {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.25rem;
  padding: 1rem 1.25rem;
  border: 1px solid var(--border);
  border-radius: 0.75rem;
  background: var(--bg-elevated);
  color: var(--text);
  cursor: pointer;
  text-align: left;
  font: inherit;
}

.mode-card:hover {
  border-color: var(--accent);
}

.mode-card-title {
  font-weight: 600;
  font-size: 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.mode-card-badge {
  font-size: 0.7rem;
  font-weight: 600;
  padding: 0.1rem 0.4rem;
  border-radius: 999px;
  background: var(--accent);
  color: var(--accent-contrast);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.mode-card-desc {
  color: var(--text-muted);
  font-size: 0.85rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.6rem 1rem;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  background: var(--bg-elevated);
  color: var(--text);
  cursor: pointer;
  font: inherit;
  font-weight: 600;
}

.btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--accent);
  color: var(--accent-contrast);
  border-color: var(--accent);
}

.btn-secondary {
  background: var(--bg-elevated);
}

.btn-submit {
  margin-top: 1rem;
  width: 100%;
  background: transparent;
  border-color: var(--accent);
  color: var(--accent);
}

.quiz .progress {
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--text-muted);
  font-size: 0.85rem;
  margin-bottom: 1rem;
}

.timer {
  font-variant-numeric: tabular-nums;
  font-weight: 600;
  color: var(--text);
}

.timer.warning {
  color: var(--danger);
}

.question {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 0.75rem;
  padding: 1.25rem;
  margin-bottom: 1rem;
}

.question-image {
  max-width: 120px;
  margin-bottom: 0.75rem;
}

.question-image svg {
  width: 100%;
  height: auto;
  display: block;
}

.question-text {
  font-size: 1.05rem;
  margin: 0;
}

.options {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.option {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.85rem 1rem;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  background: var(--bg-elevated);
  color: var(--text);
  cursor: pointer;
  text-align: left;
  font: inherit;
}

.option:hover {
  border-color: var(--accent);
}

.option.selected {
  border-color: var(--accent);
  background: color-mix(in srgb, var(--accent) 12%, var(--bg-elevated));
}

.option-letter {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.75rem;
  height: 1.75rem;
  border-radius: 999px;
  background: var(--border);
  font-weight: 600;
  font-size: 0.85rem;
  flex-shrink: 0;
}

.quiz-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
}

.quiz-dots {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem;
  justify-content: center;
  flex: 1;
}

.dot {
  width: 0.5rem;
  height: 0.5rem;
  border-radius: 999px;
  background: var(--border);
}

.dot.answered {
  background: var(--accent);
  opacity: 0.5;
}

.dot.current {
  background: var(--accent);
  opacity: 1;
  transform: scale(1.3);
}

.results .result-banner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.25rem;
  padding: 1.5rem;
  border-radius: 0.75rem;
  margin-bottom: 1.25rem;
}

.result-banner.pass {
  background: color-mix(in srgb, var(--success) 18%, var(--bg-elevated));
  border: 1px solid var(--success);
}

.result-banner.fail {
  background: color-mix(in srgb, var(--danger) 18%, var(--bg-elevated));
  border: 1px solid var(--danger);
}

.result-status {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: 0.05em;
}

.result-score {
  font-size: 1.1rem;
  font-weight: 600;
}

.result-threshold {
  color: var(--text-muted);
  font-size: 0.85rem;
}

.results-section-title {
  font-size: 1rem;
  font-weight: 600;
  margin: 0 0 0.5rem;
}

.cat-list {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  margin-bottom: 1.25rem;
}

.cat-row {
  display: flex;
  justify-content: space-between;
  padding: 0.5rem 0.75rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 0.4rem;
  font-size: 0.9rem;
}

.cat-name {
  text-transform: capitalize;
}

.cat-score {
  font-variant-numeric: tabular-nums;
  font-weight: 600;
}

.results-actions {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.back-link {
  background: none;
  border: none;
  color: var(--accent);
  cursor: pointer;
  font: inherit;
  padding: 0 0 0.75rem;
  margin-bottom: 0.25rem;
}

.progress-text {
  color: var(--text-muted);
  font-size: 0.85rem;
  font-variant-numeric: tabular-nums;
}

.feedback {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  padding: 0.85rem 1rem;
  margin-bottom: 1rem;
}

.feedback-correct {
  font-weight: 600;
  margin: 0 0 0.25rem;
}

.feedback-explanation {
  margin: 0 0 0.5rem;
  color: var(--text);
  line-height: 1.45;
}

.feedback-source {
  display: inline-block;
  color: var(--accent);
  font-size: 0.85rem;
  text-decoration: none;
  margin: 0;
}

.feedback-source:hover {
  text-decoration: underline;
}

.option.correct {
  border-color: var(--success);
  background: color-mix(in srgb, var(--success) 14%, var(--bg-elevated));
}

.option.incorrect {
  border-color: var(--danger);
  background: color-mix(in srgb, var(--danger) 14%, var(--bg-elevated));
}

.option.dimmed {
  opacity: 0.5;
}

.option:disabled {
  cursor: default;
}

.review-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin-bottom: 1.25rem;
}

.review-item {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  padding: 0.85rem 1rem;
}

.review-question {
  font-weight: 600;
  margin: 0 0 0.5rem;
}

.review-your-answer {
  margin: 0 0 0.25rem;
  color: var(--danger);
  font-size: 0.9rem;
}

.review-correct-answer {
  margin: 0 0 0.5rem;
  color: var(--success);
  font-size: 0.9rem;
}

.flag-btn, .link-btn, .question-action-btn {
  display: inline-block;
  background: none;
  border: none;
  color: var(--accent);
  cursor: pointer;
  font: inherit;
  font-size: 0.85rem;
  padding: 0;
  text-decoration: underline;
}

.flag-btn {
  margin-top: 0.75rem;
}

.link-btn {
  margin-top: 1rem;
}

.question-action-btn {
  margin-top: 0;
}

.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  z-index: 100;
}

.modal {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 0.75rem;
  padding: 1.25rem;
  max-width: 480px;
  width: 100%;
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
}

.modal-title {
  margin: 0 0 0.5rem;
  font-size: 1.1rem;
}

.modal-sub {
  margin: 0 0 1rem;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.modal-label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.modal-textarea {
  width: 100%;
  padding: 0.5rem;
  border: 1px solid var(--border);
  border-radius: 0.4rem;
  background: var(--bg);
  color: var(--text);
  font: inherit;
  font-size: 0.9rem;
  resize: vertical;
}

.modal-actions {
  display: flex;
  gap: 0.5rem;
  margin-top: 1rem;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.toast {
  position: fixed;
  bottom: 1.5rem;
  left: 50%;
  transform: translateX(-50%);
  background: var(--accent);
  color: var(--accent-contrast);
  padding: 0.6rem 1rem;
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 600;
  z-index: 200;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.question-actions {
  display: flex;
  gap: 1rem;
  margin-top: 0.75rem;
}

.home-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.5rem;
  margin-top: 1rem;
}

.resume-prompt {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 0.85rem 1rem;
  background: color-mix(in srgb, var(--accent) 10%, var(--bg-elevated));
  border: 1px solid var(--accent);
  border-radius: 0.6rem;
  margin-bottom: 1.25rem;
  flex-wrap: wrap;
}

.resume-text {
  font-weight: 600;
  font-size: 0.9rem;
}

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

.history-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.history-item {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  padding: 0.75rem 1rem;
}

.history-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.history-mode {
  font-weight: 600;
  text-transform: capitalize;
}

.history-meta {
  margin-top: 0.25rem;
  color: var(--text-muted);
  font-size: 0.85rem;
  font-variant-numeric: tabular-nums;
}

.history-badge {
  font-size: 0.7rem;
  font-weight: 700;
  padding: 0.15rem 0.5rem;
  border-radius: 999px;
  letter-spacing: 0.04em;
}

.history-badge.pass {
  background: color-mix(in srgb, var(--success) 20%, transparent);
  color: var(--success);
}

.history-badge.fail {
  background: color-mix(in srgb, var(--danger) 20%, transparent);
  color: var(--danger);
}