:root {
  --navy: #1a2f4a;
  --navy-light: #243d5c;
  --gold: #c9a227;
  --gold-muted: #e8d48a;
  --cream: #f7f5f0;
  --white: #ffffff;
  --text: #1c2836;
  --text-muted: #5a6573;
  --correct: #1e7a4c;
  --correct-bg: #e6f4ec;
  --incorrect: #b42318;
  --incorrect-bg: #fdecea;
  --border: #d8dde3;
  --shadow: 0 4px 24px rgba(26, 47, 74, 0.08);
  --radius: 10px;
  --font-sans: 'Source Sans 3', system-ui, sans-serif;
  --font-serif: 'Source Serif 4', Georgia, serif;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.55;
  color: var(--text);
  background: var(--cream);
}

.app {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Header */
.header {
  background: linear-gradient(135deg, var(--navy) 0%, var(--navy-light) 100%);
  color: var(--white);
  padding: 1.5rem 1.25rem 1.75rem;
}

.header-inner {
  max-width: 920px;
  margin: 0 auto;
}

.header-top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
  flex-wrap: wrap;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.brand-link {
  color: inherit;
  text-decoration: none;
}

.brand-link:hover h1 {
  opacity: 0.92;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.nav-user {
  font-size: 0.85rem;
  opacity: 0.9;
  margin-right: 0.25rem;
}

.btn-nav {
  font: inherit;
  font-size: 0.82rem;
  font-weight: 600;
  padding: 0.4rem 0.75rem;
  border-radius: 6px;
  border: 1px solid rgba(255, 255, 255, 0.35);
  background: rgba(255, 255, 255, 0.12);
  color: var(--white);
  cursor: pointer;
}

.btn-nav:hover {
  background: rgba(255, 255, 255, 0.2);
}

.btn-nav-ghost {
  background: transparent;
}

.brand-tag {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  background: var(--gold);
  color: var(--navy);
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  margin-bottom: 0.5rem;
}

.header h1 {
  font-family: var(--font-serif);
  font-size: 1.75rem;
  font-weight: 600;
  margin: 0 0 0.25rem;
}

.subtitle {
  margin: 0;
  opacity: 0.85;
  font-size: 0.95rem;
}

.syllabus-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-top: 1rem;
}

.syllabus-pills span {
  font-size: 0.75rem;
  padding: 0.25rem 0.6rem;
  background: rgba(255, 255, 255, 0.12);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: 999px;
}

.syllabus-pills .pill-exam {
  background: rgba(201, 162, 39, 0.35);
  border-color: rgba(201, 162, 39, 0.6);
  font-weight: 600;
}

/* Main */
.main {
  flex: 1;
  max-width: 920px;
  width: 100%;
  margin: 0 auto;
  padding: 1.5rem 1.25rem 2rem;
}

.screen {
  display: none;
}

.screen.active {
  display: block;
}

.card {
  background: var(--white);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  padding: 1.75rem;
}

.card-setup h2,
.card-results h2 {
  font-family: var(--font-serif);
  font-size: 1.4rem;
  margin: 0 0 0.75rem;
}

.lead {
  color: var(--text-muted);
  margin: 0 0 1.5rem;
}

.setup-form label {
  display: block;
  font-weight: 600;
  margin-bottom: 0.4rem;
  font-size: 0.9rem;
}

.api-key-row {
  display: flex;
  gap: 0.5rem;
}

.api-key-row input {
  flex: 1;
}

input[type='password'],
input[type='text'] {
  font: inherit;
  padding: 0.65rem 0.85rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--white);
}

input:focus {
  outline: 2px solid var(--gold);
  outline-offset: 1px;
}

.hint {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin: 0.5rem 0 1.25rem;
}

.hint a {
  color: var(--navy-light);
}

.server-config-note {
  background: var(--correct-bg);
  color: var(--correct);
  padding: 0.75rem 1rem;
  border-radius: 6px;
  margin-bottom: 1rem;
}

.server-config-note code {
  font-size: 0.85em;
}

/* Topic tabs & groups */
.topic-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-bottom: 1rem;
}

.topic-tab {
  font-size: 0.82rem;
  font-weight: 600;
  font-family: inherit;
  color: var(--navy);
  background: #eef2f7;
  padding: 0.4rem 0.7rem;
  border-radius: 999px;
  border: 1px solid var(--border);
  cursor: pointer;
}

.topic-tab:hover {
  background: var(--gold-muted);
}

.topic-tab.active {
  background: var(--navy);
  color: var(--white);
  border-color: var(--navy);
}

.topic-tab-locked:not(.active) {
  opacity: 0.75;
}

.topic-groups {
  display: flex;
  flex-direction: column;
  gap: 0;
  margin-bottom: 0;
}

.topic-group-panel.hidden {
  display: none;
}

.topic-group-actions {
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
}

.topic-group-actions .btn {
  width: 100%;
}

.topic-group {
  scroll-margin-top: 1rem;
}

.topic-group-header {
  margin-bottom: 0.65rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--border);
}

.topic-group-header h3 {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  margin: 0 0 0.2rem;
}

.topic-group-header p {
  margin: 0;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.progress-group {
  margin-bottom: 1.5rem;
}

.progress-group-title {
  font-family: var(--font-serif);
  font-size: 1rem;
  margin: 0 0 0.65rem;
  padding-bottom: 0.35rem;
  border-bottom: 1px solid var(--border);
}

/* Topic picker */
.topic-picker {
  border: none;
  margin: 0 0 1.25rem;
  padding: 0;
}

.topic-picker legend {
  font-weight: 600;
  font-size: 0.9rem;
  margin-bottom: 0.65rem;
}

.topic-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 0.5rem;
}

.topic-option {
  display: block;
  cursor: pointer;
}

.topic-option input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.topic-card {
  display: block;
  padding: 0.75rem 0.85rem;
  border: 2px solid var(--border);
  border-radius: 8px;
  background: var(--white);
  transition: border-color 0.15s, background 0.15s, box-shadow 0.15s;
  height: 100%;
}

.topic-option input:checked + .topic-card {
  border-color: var(--navy);
  background: #f0f4f8;
  box-shadow: 0 0 0 1px var(--navy);
}

.topic-option:hover .topic-card {
  border-color: var(--navy-light);
}

.topic-card-exam {
  border-color: var(--gold);
  background: linear-gradient(135deg, #fffdf5 0%, #fff 100%);
}

.topic-option input:checked + .topic-card-exam {
  border-color: var(--gold);
  background: #fff9e6;
  box-shadow: 0 0 0 1px var(--gold);
}

.topic-code {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--navy);
  background: var(--gold-muted);
  padding: 0.15rem 0.45rem;
  border-radius: 4px;
  margin-bottom: 0.35rem;
}

.topic-title {
  display: block;
  font-weight: 600;
  font-size: 0.92rem;
  line-height: 1.3;
  margin-bottom: 0.2rem;
}

.topic-desc {
  display: block;
  font-size: 0.78rem;
  color: var(--text-muted);
  line-height: 1.35;
}

.test-label {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--navy);
  margin: 0 0 0.85rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border);
  line-height: 1.35;
}

.results-topic {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-muted);
  margin: 0 0 0.25rem;
}

/* Buttons */
.btn {
  font: inherit;
  font-weight: 600;
  cursor: pointer;
  border: none;
  border-radius: 6px;
  padding: 0.6rem 1.1rem;
  transition: background 0.15s, opacity 0.15s;
}

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

.btn-primary {
  background: var(--navy);
  color: var(--white);
}

.btn-primary:hover:not(:disabled) {
  background: var(--navy-light);
}

.btn-secondary {
  background: var(--gold-muted);
  color: var(--navy);
}

.btn-secondary:hover:not(:disabled) {
  background: var(--gold);
}

.btn-ghost {
  background: transparent;
  color: var(--navy);
  border: 1px solid var(--border);
}

.btn-lg {
  width: 100%;
  padding: 0.85rem;
  font-size: 1rem;
}

.error-banner {
  margin-top: 1rem;
  padding: 0.85rem 1rem;
  background: var(--incorrect-bg);
  color: var(--incorrect);
  border-radius: 6px;
  font-size: 0.9rem;
}

.loading {
  text-align: center;
  padding: 2rem 0;
}

.spinner {
  width: 36px;
  height: 36px;
  border: 3px solid var(--border);
  border-top-color: var(--navy);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin: 0 auto 1rem;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.hidden {
  display: none !important;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

/* Quiz layout */
.quiz-layout {
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 1.25rem;
  align-items: start;
}

@media (max-width: 640px) {
  .quiz-layout {
    grid-template-columns: 1fr;
  }
}

.score-panel {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem;
  box-shadow: var(--shadow);
}

.score-stat {
  margin-bottom: 0.75rem;
}

.score-label {
  display: block;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-muted);
}

.score-value {
  font-size: 1.5rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
}

.score-stat.correct .score-value { color: var(--correct); }
.score-stat.incorrect .score-value { color: var(--incorrect); }

.progress-bar {
  height: 6px;
  background: var(--border);
  border-radius: 999px;
  overflow: hidden;
  margin-top: 0.5rem;
}

.progress-fill {
  height: 100%;
  background: var(--gold);
  width: 0%;
  transition: width 0.3s ease;
}

.topic-badge {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--navy);
  background: var(--gold-muted);
  padding: 0.25rem 0.65rem;
  border-radius: 999px;
  margin: 0 0 1rem;
}

.question-text {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 600;
  line-height: 1.45;
  margin: 0 0 1.25rem;
}

.options {
  border: none;
  margin: 0;
  padding: 0;
}

.option {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 0.85rem 1rem;
  margin-bottom: 0.5rem;
  border: 2px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
}

.option:hover:not(.disabled) {
  border-color: var(--navy-light);
  background: #fafbfc;
}

.option.selected {
  border-color: var(--navy);
  background: #f0f4f8;
}

.option.correct {
  border-color: var(--correct);
  background: var(--correct-bg);
}

.option.incorrect {
  border-color: var(--incorrect);
  background: var(--incorrect-bg);
}

.option.disabled {
  cursor: default;
}

.option-letter {
  flex-shrink: 0;
  width: 1.75rem;
  height: 1.75rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.85rem;
  background: var(--navy);
  color: var(--white);
  border-radius: 50%;
}

.option.correct .option-letter { background: var(--correct); }
.option.incorrect .option-letter { background: var(--incorrect); }

.option-text {
  flex: 1;
  padding-top: 0.1rem;
}

.feedback {
  margin: 1rem 0;
  padding: 0.85rem 1rem;
  border-radius: 6px;
  font-size: 0.95rem;
}

.feedback.correct {
  background: var(--correct-bg);
  color: var(--correct);
}

.feedback.incorrect {
  background: var(--incorrect-bg);
  color: var(--incorrect);
}

.feedback .explanation {
  margin: 0.5rem 0 0;
  color: var(--text);
  font-size: 0.9rem;
}

.quiz-actions {
  display: flex;
  gap: 0.75rem;
  margin-top: 0.5rem;
}

/* Results */
.results-score {
  font-family: var(--font-serif);
  font-size: 2.5rem;
  font-weight: 600;
  color: var(--navy);
  margin-bottom: 0.25rem;
}

.results-summary {
  color: var(--text-muted);
  margin: 0 0 1.5rem;
}

.review-list {
  border-top: 1px solid var(--border);
  padding-top: 1rem;
  margin-bottom: 1.5rem;
}

.review-item {
  padding: 0.85rem 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.9rem;
}

.review-item:last-child {
  border-bottom: none;
}

.review-item .review-q {
  font-weight: 600;
  margin-bottom: 0.35rem;
}

.review-item .review-meta {
  color: var(--text-muted);
  font-size: 0.82rem;
}

.review-item.pass .review-result { color: var(--correct); }
.review-item.fail .review-result { color: var(--incorrect); }

.results-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.footer {
  padding: 1rem 1.25rem;
  text-align: center;
  font-size: 0.78rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border);
}

.footer p {
  max-width: 640px;
  margin: 0 auto;
}

.footer a {
  color: var(--navy);
  font-weight: 500;
}

/* Auth */
.card-auth h2,
.card-progress h2 {
  font-family: var(--font-serif);
  font-size: 1.4rem;
  margin: 0 0 0.75rem;
}

.auth-form label {
  display: block;
  font-weight: 600;
  margin: 0.75rem 0 0.4rem;
  font-size: 0.9rem;
}

.auth-form input {
  width: 100%;
  font: inherit;
  padding: 0.65rem 0.85rem;
  border: 1px solid var(--border);
  border-radius: 6px;
}

.auth-form .btn-lg {
  margin-top: 1.25rem;
}

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

.btn-link {
  font: inherit;
  font-weight: 600;
  color: var(--navy);
  background: none;
  border: none;
  padding: 0;
  cursor: pointer;
  text-decoration: underline;
}

/* Progress dashboard */
.section-heading {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  margin: 1.5rem 0 0.75rem;
}

.progress-overview {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 0.75rem;
  margin-bottom: 0.5rem;
}

.stat-card {
  background: #f8f9fb;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.85rem 1rem;
}

.stat-card .stat-label {
  display: block;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-muted);
}

.stat-card .stat-value {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--navy);
}

.progress-topic-grid {
  display: grid;
  gap: 0.65rem;
}

.progress-topic-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 0.75rem;
  align-items: center;
  padding: 0.85rem 1rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--white);
}

@media (max-width: 640px) {
  .progress-topic-row {
    grid-template-columns: 1fr;
  }
}

.progress-topic-info .topic-code {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--navy);
  background: var(--gold-muted);
  padding: 0.15rem 0.45rem;
  border-radius: 4px;
  margin-bottom: 0.25rem;
}

.progress-topic-info .topic-title {
  display: block;
  font-weight: 600;
  font-size: 0.95rem;
}

.progress-topic-stats {
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
}

.progress-topic-actions {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.progress-topic-actions .btn {
  font-size: 0.82rem;
  padding: 0.45rem 0.75rem;
}

.progress-bar-inline {
  height: 6px;
  background: var(--border);
  border-radius: 999px;
  overflow: hidden;
  margin-top: 0.5rem;
  max-width: 280px;
}

.progress-bar-inline-fill {
  height: 100%;
  background: var(--correct);
  border-radius: 999px;
}

.progress-history-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.88rem;
}

.progress-history-item:last-child {
  border-bottom: none;
}

.progress-history-meta {
  color: var(--text-muted);
  font-size: 0.78rem;
}

.progress-empty {
  color: var(--text-muted);
  font-size: 0.9rem;
  padding: 0.5rem 0;
}

.save-status {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 0.5rem;
}

.save-status.success { color: var(--correct); }
.save-status.error { color: var(--incorrect); }