/* ===== Reset & Base ===== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --bg: #0f1117;
  --bg-surface: #1a1d27;
  --bg-elevated: #242736;
  --text: #e4e4e7;
  --text-muted: #9ca3af;
  --border: #2e3345;
  --accent: #6366f1;
  --accent-hover: #818cf8;
  --green: #22c55e;
  --green-bg: rgba(34, 197, 94, 0.15);
  --yellow: #eab308;
  --yellow-bg: rgba(234, 179, 8, 0.15);
  --red: #ef4444;
  --red-bg: rgba(239, 68, 68, 0.15);
}

html, body {
  height: 100%;
  overflow: hidden;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--bg);
  color: var(--text);
}

.hidden {
  display: none !important;
}

/* ===== Landing Screen ===== */
#landing-screen {
  position: fixed;
  inset: 0;
  z-index: 200;
  background: var(--bg);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 20px;
  cursor: pointer;
  transition: opacity 0.5s ease;
}

#landing-screen.fade-out {
  opacity: 0;
  pointer-events: none;
}

#landing-prof-wrapper {
  width: 150px;
  height: 150px;
  overflow: hidden;
  transition: transform 0.3s;
}

#landing-prof-wrapper:hover {
  transform: scale(1.05);
}

#landing-prof-wrapper.spinning {
  animation: spin360 1.4s ease-in forwards;
}

@keyframes spin360 {
  0% { transform: rotate(0deg) scale(1); }
  100% { transform: rotate(360deg) scale(14); }
}

#landing-prof {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
}

#landing-text {
  font-size: 16px;
  color: var(--text-muted);
  font-style: italic;
  letter-spacing: 0.5px;
}

/* ===== How It Works Overlay ===== */
#how-it-works-overlay {
  position: fixed;
  inset: 0;
  z-index: 200;
  background: rgba(0, 0, 0, 0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  animation: fadeIn 0.3s ease;
}

#how-it-works-card {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 32px 36px;
  max-width: 480px;
  width: 90%;
  box-shadow: 0 8px 40px rgba(0, 0, 0, 0.3);
}

#how-it-works-card h2 {
  font-size: 20px;
  font-weight: 700;
  margin-bottom: 18px;
  color: var(--text);
}

#how-it-works-card ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 24px;
}

#how-it-works-card li {
  font-size: 14px;
  line-height: 1.5;
  color: var(--text-muted);
  padding-left: 20px;
  position: relative;
}

#how-it-works-card li::before {
  content: '•';
  position: absolute;
  left: 0;
  color: var(--accent);
  font-weight: 700;
}

#how-it-works-card li strong {
  color: var(--text);
}

#how-it-works-dismiss {
  width: 100%;
  padding: 10px;
  border-radius: 8px;
  border: none;
  background: var(--accent);
  color: #fff;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s;
}

#how-it-works-dismiss:hover {
  background: var(--accent-hover);
}

/* ===== Help Button ===== */
#help-btn {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text-muted);
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.15s;
  margin-left: auto;
  flex-shrink: 0;
}

#help-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* ===== Filter Bar ===== */
#filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  padding: 10px 20px;
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border);
  align-items: center;
}

.filter-group {
  display: flex;
  align-items: center;
  gap: 6px;
}

.filter-label {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.filter-chips {
  display: flex;
  gap: 4px;
}

.chip {
  padding: 4px 12px;
  border-radius: 16px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text-muted);
  font-size: 12px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s ease;
}

.chip.active {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

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

.chip.bucket-red.active { background: var(--red); border-color: var(--red); }
.chip.bucket-yellow.active { background: var(--yellow); border-color: var(--yellow); }
.chip.bucket-green.active { background: var(--green); border-color: var(--green); }

/* ===== Split Panel ===== */
#split-panel {
  display: flex;
  height: calc(100vh - 48px);
}

#pdf-panel {
  flex: 1 1 55%;
  min-width: 300px;
  background: #1e1e1e;
}

#pdf-viewer {
  width: 100%;
  height: 100%;
  border: none;
}

#divider {
  width: 4px;
  cursor: col-resize;
  background: var(--border);
  transition: background 0.15s;
  flex-shrink: 0;
}

#divider:hover,
#divider.dragging {
  background: var(--accent);
}

#quiz-panel {
  flex: 1 1 45%;
  min-width: 320px;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 24px 20px;
  overflow-y: auto;
  gap: 18px;
}

/* ===== Prof Face ===== */
#prof-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  cursor: pointer;
}

#prof-face-wrapper {
  width: 100px;
  height: 100px;
  overflow: hidden;
  transition: transform 0.3s ease;
}

#prof-face-wrapper:hover {
  transform: scale(1.05);
}

#prof-face {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
}

#prof-face-wrapper.thinking {
  animation: think 0.8s ease-in-out;
}

@keyframes think {
  0% { transform: rotate(0deg) scale(1.05); }
  100% { transform: rotate(360deg) scale(1); }
}

#prof-prompt {
  font-size: 13px;
  color: var(--text-muted);
  font-style: italic;
}

/* ===== Question Card ===== */
#question-card {
  width: 100%;
  max-width: 520px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
  box-shadow: 0 1px 4px rgba(0,0,0,0.06);
  animation: fadeIn 0.3s ease;
}

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

#question-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
}

#question-type-badge {
  padding: 3px 10px;
  border-radius: 10px;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.badge-definition { background: #3b82f6; color: #fff; }
.badge-result { background: #8b5cf6; color: #fff; }

#question-label {
  font-size: 13px;
  color: var(--text-muted);
  font-weight: 500;
}

#question-statement {
  font-size: 15px;
  line-height: 1.7;
  color: var(--text);
}

#question-statement .katex {
  font-size: 1em;
}

.link-btn {
  display: inline-block;
  margin-top: 12px;
  padding: 6px 14px;
  border-radius: 6px;
  border: 1px solid var(--accent);
  background: transparent;
  color: var(--accent);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s;
}

.link-btn:hover {
  background: var(--accent);
  color: #fff;
}

/* ===== Bucket Buttons ===== */
#bucket-buttons {
  display: flex;
  gap: 10px;
  width: 100%;
  max-width: 520px;
  justify-content: center;
}

.bucket-btn {
  flex: 1;
  padding: 10px 6px;
  border-radius: 8px;
  border: 2px solid transparent;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s ease;
}

.bucket-btn.green {
  background: var(--green-bg);
  color: var(--green);
  border-color: var(--green);
}
.bucket-btn.green:hover { background: var(--green); color: #fff; }

.bucket-btn.yellow {
  background: var(--yellow-bg);
  color: var(--yellow);
  border-color: var(--yellow);
}
.bucket-btn.yellow:hover { background: var(--yellow); color: #fff; }

.bucket-btn.red {
  background: var(--red-bg);
  color: var(--red);
  border-color: var(--red);
}
.bucket-btn.red:hover { background: var(--red); color: #fff; }

.bucket-btn.skip {
  background: var(--bg-surface);
  color: var(--text-muted);
  border-color: var(--border);
  flex: 0.6;
}
.bucket-btn.skip:hover { border-color: var(--text-muted); color: var(--text); }

/* ===== Stats Panel ===== */
#stats-panel {
  width: 100%;
  max-width: 520px;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px;
}

#stats-panel h3 {
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-muted);
  margin-bottom: 10px;
}

#stats-summary {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 14px;
}

#stat-total {
  font-size: 16px;
  font-weight: 600;
}

#stat-buckets {
  display: flex;
  gap: 8px;
}

.stat-chip {
  padding: 2px 10px;
  border-radius: 10px;
  font-size: 13px;
  font-weight: 600;
}

.stat-chip.green { background: var(--green-bg); color: var(--green); }
.stat-chip.yellow { background: var(--yellow-bg); color: var(--yellow); }
.stat-chip.red { background: var(--red-bg); color: var(--red); }

/* Chapter progress bars — clickable */
#chapter-progress {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 14px;
}

.chapter-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  padding: 3px 4px;
  border-radius: 6px;
  transition: background 0.15s;
}

.chapter-bar:hover {
  background: var(--bg-elevated);
}

.chapter-bar-label {
  font-size: 12px;
  color: var(--accent);
  font-weight: 600;
  width: 36px;
  flex-shrink: 0;
  text-decoration: underline;
}

.chapter-bar-track {
  flex: 1;
  height: 8px;
  background: var(--bg-elevated);
  border-radius: 4px;
  overflow: hidden;
  display: flex;
}

.chapter-bar-fill-green {
  height: 100%;
  background: var(--green);
  transition: width 0.3s ease;
}

.chapter-bar-fill-yellow {
  height: 100%;
  background: var(--yellow);
  transition: width 0.3s ease;
}

.chapter-bar-fill-red {
  height: 100%;
  background: var(--red);
  transition: width 0.3s ease;
}

.chapter-bar-count {
  font-size: 11px;
  color: var(--text-muted);
  width: 40px;
  text-align: right;
  flex-shrink: 0;
}

/* Quick filter buttons */
#quick-filters {
  display: flex;
  gap: 8px;
}

.quick-filter-btn {
  flex: 1;
  padding: 8px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text-muted);
  font-size: 12px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s;
}

.quick-filter-btn:hover {
  border-color: var(--accent);
  color: var(--text);
}

#review-red:hover { border-color: var(--red); color: var(--red); }
#review-yellow:hover { border-color: var(--yellow); color: var(--yellow); }

/* ===== Chapter Detail Modal ===== */
.modal {
  position: fixed;
  inset: 0;
  z-index: 100;
  background: rgba(0,0,0,0.3);
  display: flex;
  align-items: center;
  justify-content: center;
  animation: fadeIn 0.2s ease;
}

.modal-content {
  background: var(--bg);
  border-radius: 16px;
  box-shadow: 0 8px 40px rgba(0,0,0,0.15);
  width: 90%;
  max-width: 95vw;
  max-height: 85vh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 24px;
  border-bottom: 1px solid var(--border);
}

.modal-header h2 {
  font-size: 18px;
  font-weight: 700;
}

#modal-close {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  border: none;
  background: var(--bg-surface);
  color: var(--text);
  font-size: 20px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s;
}

#modal-close:hover {
  background: var(--bg-elevated);
}

#modal-body {
  padding: 16px 24px;
  overflow-y: auto;
  flex: 1;
}

/* Chapter table */
.chapter-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}

.chapter-table th {
  text-align: left;
  padding: 8px 10px;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-muted);
  border-bottom: 2px solid var(--border);
  background: var(--bg-surface);
  position: sticky;
  top: 0;
}

.chapter-table td {
  padding: 10px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}

.chapter-table tr {
  cursor: pointer;
  transition: background 0.1s;
}

.chapter-table tr:hover {
  background: var(--bg-surface);
}

.chapter-table .type-cell {
  font-weight: 600;
  font-size: 11px;
  text-transform: uppercase;
  white-space: nowrap;
}

.chapter-table .type-def { color: #60a5fa; }
.chapter-table .type-result { color: #a78bfa; }

.chapter-table .statement-cell {
  line-height: 1.6;
}

.chapter-table .status-cell {
  text-align: center;
  font-size: 16px;
}

.status-dot {
  display: inline-block;
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

.status-dot.green { background: var(--green); }
.status-dot.yellow { background: var(--yellow); }
.status-dot.red { background: var(--red); }
.status-dot.unseen { background: var(--border); }

/* ===== Database Button ===== */
.database-btn {
  width: 100%;
  max-width: 520px;
  text-align: center;
  padding: 10px;
  font-size: 14px;
  font-weight: 600;
}

/* ===== Database Modal ===== */
.database-modal-content {
  max-width: 95vw !important;
  width: 95% !important;
  max-height: 90vh;
}

#database-search-wrapper {
  padding: 12px 24px;
  border-bottom: 1px solid var(--border);
}

#database-search {
  width: 100%;
  padding: 10px 14px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg-surface);
  color: var(--text);
  font-size: 14px;
  font-family: inherit;
  outline: none;
  transition: border-color 0.15s;
}

#database-search:focus {
  border-color: var(--accent);
}

#database-search::placeholder {
  color: var(--text-muted);
}

#database-body {
  padding: 0 24px 16px;
  overflow-y: auto;
  flex: 1;
}

.db-chapter-heading {
  font-size: 13px;
  font-weight: 700;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  padding: 14px 0 6px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 4px;
}

.db-item {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 8px 6px;
  border-radius: 6px;
  cursor: pointer;
  transition: background 0.1s;
  border-bottom: 1px solid var(--border);
}

.db-item:hover {
  background: var(--bg-elevated);
}

.db-item-number {
  font-weight: 700;
  font-size: 13px;
  color: var(--text);
  white-space: nowrap;
  min-width: 40px;
}

.db-item-type {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  white-space: nowrap;
  min-width: 70px;
}

.db-item-name {
  font-size: 13px;
  color: var(--text-muted);
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.db-item-name strong {
  color: var(--text);
}

.db-item-preview {
  font-size: 13px;
  color: var(--text-muted);
  font-style: italic;
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.db-no-results {
  padding: 20px;
  text-align: center;
  color: var(--text-muted);
  font-size: 14px;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  #split-panel {
    flex-direction: column;
  }
  #pdf-panel {
    height: 40vh;
    min-width: unset;
  }
  #divider {
    width: 100%;
    height: 4px;
    cursor: row-resize;
  }
  #quiz-panel {
    min-width: unset;
  }
}