/* ============== Cert Mastery — PWA Styles ============== */
:root {
  --bg: #0f172a;
  --bg-2: #1e293b;
  --bg-3: #334155;
  --text: #e2e8f0;
  --text-2: #94a3b8;
  --text-3: #64748b;
  --accent: #6366f1;
  --accent-2: #818cf8;
  --success: #10b981;
  --success-2: #34d399;
  --error: #ef4444;
  --error-2: #f87171;
  --warning: #f59e0b;
  --border: #334155;
  --card: #1e293b;
  --card-2: #273548;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 25px -3px rgba(0, 0, 0, 0.5);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html, body {
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
}

#app {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  max-width: 900px;
  margin: 0 auto;
  padding-bottom: 80px;
}

/* ============== Header ============== */
.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  background: var(--bg-2);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.app-title {
  font-size: 1.25rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--accent-2), var(--success-2));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  flex: 1;
  text-align: center;
}

.back-btn {
  background: transparent;
  border: none;
  color: var(--text);
  font-size: 1.75rem;
  font-weight: 300;
  cursor: pointer;
  padding: 0 12px;
  display: none;
  line-height: 1;
}

.back-btn.visible { display: block; }

.header-spacer { width: 36px; }

/* ============== Screens ============== */
.screen {
  display: none;
  padding: 24px 20px;
  animation: fadeIn 0.25s ease;
}

.screen.active { display: block; }

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.hero {
  margin-bottom: 24px;
}

.hero h2 {
  font-size: 1.5rem;
  margin-bottom: 6px;
}

.hero-sub {
  color: var(--text-2);
  font-size: 0.95rem;
}

/* ============== Cert Grid ============== */
.cert-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
  margin-bottom: 24px;
}

.cert-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  cursor: pointer;
  transition: all 0.2s;
  text-align: left;
  color: var(--text);
  font: inherit;
  display: block;
  width: 100%;
}

.cert-card:hover {
  border-color: var(--accent);
  background: var(--card-2);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.cert-card-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 12px;
  margin-bottom: 10px;
}

.cert-name {
  font-size: 1.15rem;
  font-weight: 700;
  flex: 1;
}

.cert-badge {
  background: var(--accent);
  color: white;
  padding: 4px 10px;
  border-radius: 99px;
  font-size: 0.75rem;
  font-weight: 600;
  white-space: nowrap;
}

.cert-desc {
  color: var(--text-2);
  font-size: 0.9rem;
  margin-bottom: 10px;
}

.cert-meta {
  display: flex;
  gap: 16px;
  font-size: 0.85rem;
  color: var(--text-3);
}

.cert-meta span { display: flex; align-items: center; gap: 4px; }

/* ============== Stats Card ============== */
.stats-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
}

.stats-card h3 {
  font-size: 1rem;
  margin-bottom: 12px;
  color: var(--text-2);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  font-weight: 600;
}

.stat-row {
  display: flex;
  justify-content: space-between;
  padding: 6px 0;
  border-bottom: 1px solid var(--border);
}

.stat-row:last-child { border-bottom: none; }

.stat-row .stat-label { color: var(--text-2); font-size: 0.9rem; }
.stat-row .stat-value { font-weight: 600; }

.muted { color: var(--text-3); font-size: 0.9rem; }

/* ============== Action Grid (Cert Menu) ============== */
.cert-header {
  margin-bottom: 24px;
}

.cert-header h2 {
  font-size: 1.4rem;
  margin-bottom: 4px;
}

.action-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  margin-bottom: 24px;
}

.action-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  cursor: pointer;
  transition: all 0.2s;
  text-align: left;
  color: var(--text);
  font: inherit;
}

.action-card:hover {
  border-color: var(--accent);
  background: var(--card-2);
}

.action-icon {
  font-size: 2rem;
  margin-bottom: 8px;
}

.action-card h3 {
  font-size: 1.1rem;
  margin-bottom: 4px;
}

.action-card p {
  color: var(--text-2);
  font-size: 0.9rem;
}

.cert-stats {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
}

/* ============== Notes ============== */
.notes-header {
  margin-bottom: 20px;
}

.notes-header h2 { font-size: 1.3rem; margin-bottom: 4px; }

.notes-toc {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 24px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px;
  position: sticky;
  top: 70px;
  z-index: 10;
  max-height: 240px;
  overflow-y: auto;
}

.toc-link {
  background: transparent;
  border: none;
  color: var(--text-2);
  text-align: left;
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font: inherit;
  font-size: 0.9rem;
  transition: all 0.15s;
}

.toc-link:hover {
  background: var(--card-2);
  color: var(--text);
}

.toc-link.active {
  background: var(--accent);
  color: white;
  font-weight: 500;
}

.notes-content {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
}

.notes-section {
  margin-bottom: 32px;
  scroll-margin-top: 320px;
}

.notes-section h3 {
  font-size: 1.15rem;
  margin-bottom: 12px;
  color: var(--accent-2);
  border-bottom: 1px solid var(--border);
  padding-bottom: 8px;
}

.notes-section h4 {
  font-size: 1rem;
  margin: 16px 0 8px;
  color: var(--text);
}

.notes-section p, .notes-section li {
  color: var(--text-2);
  margin-bottom: 8px;
  line-height: 1.6;
}

.notes-section ul, .notes-section ol {
  margin-left: 24px;
  margin-bottom: 12px;
}

.notes-section code {
  background: var(--bg-3);
  padding: 1px 6px;
  border-radius: 4px;
  font-family: ui-monospace, "SF Mono", Consolas, monospace;
  font-size: 0.85em;
  color: var(--success-2);
}

.notes-section strong { color: var(--text); font-weight: 600; }

.notes-section table {
  width: 100%;
  border-collapse: collapse;
  margin: 12px 0;
  font-size: 0.9rem;
}

.notes-section th, .notes-section td {
  border: 1px solid var(--border);
  padding: 8px 10px;
  text-align: left;
  color: var(--text-2);
}

.notes-section th {
  background: var(--bg-3);
  color: var(--text);
  font-weight: 600;
}

/* ============== Forms (Test Setup) ============== */
.form-group {
  margin-bottom: 20px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
}

.form-group label {
  display: block;
  margin-bottom: 10px;
  font-weight: 500;
}

.range-row {
  display: flex;
  align-items: center;
  gap: 12px;
}

input[type="range"] {
  flex: 1;
  accent-color: var(--accent);
}

.range-value {
  background: var(--accent);
  color: white;
  padding: 4px 12px;
  border-radius: 99px;
  font-weight: 600;
  min-width: 40px;
  text-align: center;
}

.checkbox-label {
  display: flex !important;
  align-items: center;
  gap: 10px;
  cursor: pointer;
}

.checkbox-label input {
  width: 18px;
  height: 18px;
  accent-color: var(--accent);
}

/* ============== Buttons ============== */
.btn {
  background: var(--accent);
  color: white;
  border: none;
  border-radius: var(--radius-sm);
  padding: 12px 20px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s;
  font-family: inherit;
}

.btn:hover { background: var(--accent-2); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

.btn-primary { background: var(--accent); }
.btn-secondary { background: var(--bg-3); color: var(--text); }
.btn-secondary:hover { background: #475569; }
.btn-large { padding: 14px 28px; font-size: 1.05rem; width: 100%; }
.btn-small { padding: 6px 12px; font-size: 0.85rem; }

.btn-link {
  background: transparent;
  color: var(--text-3);
  border: none;
  cursor: pointer;
  font: inherit;
  font-size: 0.85rem;
  text-decoration: underline;
  margin-top: 12px;
  padding: 0;
}

/* ============== Quiz ============== */
.quiz-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
  gap: 12px;
}

.quiz-progress { flex: 1; }

#progressText {
  font-size: 0.9rem;
  color: var(--text-2);
  margin-bottom: 6px;
  display: block;
}

.progress-bar {
  height: 6px;
  background: var(--bg-3);
  border-radius: 99px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--success));
  width: 0%;
  transition: width 0.3s;
}

.timer {
  display: flex;
  align-items: center;
  gap: 6px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 6px 12px;
  font-size: 0.95rem;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

.timer-icon { font-size: 1.1rem; }

.timer.warning {
  background: var(--warning);
  color: var(--bg);
  animation: pulse 1s infinite;
}

.timer.danger {
  background: var(--error);
  color: white;
  animation: pulse 0.5s infinite;
}

@keyframes pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.05); }
}

.question-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
}

.question-card h2 {
  font-size: 1.1rem;
  line-height: 1.5;
  margin-bottom: 20px;
  font-weight: 600;
}

.options {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 16px;
}

.option {
  background: var(--bg-2);
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 14px 16px;
  cursor: pointer;
  text-align: left;
  color: var(--text);
  font: inherit;
  font-size: 0.95rem;
  transition: all 0.15s;
  display: flex;
  align-items: flex-start;
  gap: 10px;
  line-height: 1.4;
}

.option:hover:not(:disabled):not(.correct):not(.incorrect) {
  border-color: var(--accent);
  background: var(--card-2);
}

.option-marker {
  background: var(--bg-3);
  color: var(--text-2);
  width: 26px;
  height: 26px;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.85rem;
  flex-shrink: 0;
}

.option.correct {
  background: rgba(16, 185, 129, 0.15);
  border-color: var(--success);
  color: var(--text);
}

.option.correct .option-marker {
  background: var(--success);
  color: white;
}

.option.incorrect {
  background: rgba(239, 68, 68, 0.15);
  border-color: var(--error);
  color: var(--text);
}

.option.incorrect .option-marker {
  background: var(--error);
  color: white;
}

.option:disabled { cursor: default; }

.feedback {
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-left: 4px solid var(--accent);
  border-radius: var(--radius-sm);
  padding: 14px 16px;
  margin-bottom: 16px;
}

.feedback.correct { border-left-color: var(--success); }
.feedback.incorrect { border-left-color: var(--error); }

.feedback-title {
  font-weight: 700;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.feedback-text { color: var(--text-2); font-size: 0.92rem; line-height: 1.5; }

.question-actions {
  display: flex;
  gap: 10px;
  margin-top: 8px;
}

.question-actions .btn { flex: 1; }

/* ============== Results ============== */
.results-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 20px;
  text-align: center;
  margin-bottom: 20px;
}

.results-card h2 {
  font-size: 1.5rem;
  margin-bottom: 18px;
}

.score-circle {
  width: 140px;
  height: 140px;
  border-radius: 50%;
  background: conic-gradient(var(--accent) 0%, var(--bg-3) 0%);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
  position: relative;
}

.score-circle::after {
  content: '';
  position: absolute;
  inset: 8px;
  background: var(--card);
  border-radius: 50%;
}

.score-percent, .score-label {
  position: relative;
  z-index: 1;
}

.score-percent {
  font-size: 2rem;
  font-weight: 700;
}

.score-label {
  font-size: 0.85rem;
  color: var(--text-2);
}

#scoreMessage {
  color: var(--text-2);
  margin-bottom: 18px;
  font-size: 0.95rem;
}

.results-actions {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.results-actions .btn { width: 100%; }

/* Review */
.review-container { margin-top: 8px; }

.review-item {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  margin-bottom: 12px;
}

.review-item.correct { border-left: 4px solid var(--success); }
.review-item.incorrect { border-left: 4px solid var(--error); }

.review-item-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 10px;
  font-size: 0.85rem;
  color: var(--text-2);
}

.review-item .q {
  font-weight: 600;
  margin-bottom: 10px;
  color: var(--text);
}

.review-item .ans {
  font-size: 0.9rem;
  color: var(--text-2);
  margin-bottom: 4px;
}

.review-item .ans.your { color: var(--error-2); }
.review-item .ans.correct-ans { color: var(--success-2); }
.review-item .ans.was { color: var(--text-3); font-style: italic; }

.review-item .explanation {
  background: var(--bg-2);
  border-radius: var(--radius-sm);
  padding: 10px;
  font-size: 0.88rem;
  color: var(--text-2);
  margin-top: 10px;
  line-height: 1.5;
}

/* ============== Install Banner ============== */
.install-banner {
  position: fixed;
  bottom: 16px;
  left: 16px;
  right: 16px;
  background: var(--card-2);
  border: 1px solid var(--accent);
  border-radius: var(--radius);
  padding: 12px 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  box-shadow: var(--shadow-lg);
  z-index: 200;
  max-width: 600px;
  margin: 0 auto;
}

.install-text strong { display: block; font-size: 0.95rem; }
.install-text p { font-size: 0.8rem; color: var(--text-2); margin: 0; }

.install-actions { display: flex; gap: 8px; }

/* ============== Responsive ============== */
@media (min-width: 600px) {
  .cert-grid { grid-template-columns: 1fr 1fr; }
  .action-grid { grid-template-columns: 1fr 1fr 1fr; }
  .results-actions { flex-direction: row; }
  .results-actions .btn { flex: 1; }
}

@media (max-width: 480px) {
  .hero h2 { font-size: 1.3rem; }
  .cert-name { font-size: 1.05rem; }
  .score-circle { width: 120px; height: 120px; }
  .score-percent { font-size: 1.7rem; }
  .question-card h2 { font-size: 1rem; }
}