/* ============================================
   CDMP Exam Prep - style.css
   Premium study platform, dark/light mode
   ============================================ */

/* --- CSS Variables (Dark Mode Default) --- */
:root {
  --bg: #0f1117;
  --bg-card: #1a1d27;
  --bg-sidebar: #14161f;
  --bg-elevated: #222533;
  --bg-input: #1a1d27;
  --border: #2a2d3a;
  --border-focus: #4f6ef7;
  --text: #e1e4ed;
  --text-secondary: #8b8fa7;
  --text-muted: #5a5e73;
  --accent: #4f6ef7;
  --accent-hover: #3d5bd9;
  --accent-light: rgba(79,110,247,0.15);
  --success: #22c55e;
  --success-bg: rgba(34,197,94,0.12);
  --danger: #ef4444;
  --danger-bg: rgba(239,68,68,0.12);
  --warning: #f59e0b;
  --radius: 10px;
  --radius-sm: 6px;
  --shadow: 0 2px 8px rgba(0,0,0,0.3);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.4);
  --transition: 0.2s cubic-bezier(0.4,0,0.2,1);
  --sidebar-w: 320px;
  --topbar-h: 56px;
  --font: 'Inter', 'Segoe UI', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', 'Cascadia Code', 'Fira Code', monospace;
}

/* --- Light Mode --- */
[data-theme="light"] {
  --bg: #f5f6fa;
  --bg-card: #ffffff;
  --bg-sidebar: #f0f1f5;
  --bg-elevated: #ffffff;
  --bg-input: #eef0f5;
  --border: #dde0e8;
  --border-focus: #4f6ef7;
  --text: #1a1d2e;
  --text-secondary: #5a5e73;
  --text-muted: #9ca0b5;
  --accent: #4f6ef7;
  --accent-hover: #3d5bd9;
  --accent-light: rgba(79,110,247,0.1);
  --success: #16a34a;
  --success-bg: rgba(22,163,74,0.1);
  --danger: #dc2626;
  --danger-bg: rgba(220,38,38,0.1);
  --shadow: 0 2px 8px rgba(0,0,0,0.06);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.1);
}

/* --- Reset & Base --- */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{font-size:16px;-webkit-text-size-adjust:100%}
body{
  font-family:var(--font);
  background:var(--bg);
  color:var(--text);
  line-height:1.6;
  min-height:100vh;
  overflow-x:hidden;
  transition:background var(--transition),color var(--transition);
}

/* --- Theme Toggle --- */
.theme-toggle{
  position:fixed;top:12px;right:12px;z-index:1000;
  width:40px;height:40px;border-radius:50%;
  border:1px solid var(--border);
  background:var(--bg-card);
  color:var(--text);
  font-size:1.2rem;cursor:pointer;
  display:flex;align-items:center;justify-content:center;
  transition:all var(--transition);
  box-shadow:var(--shadow);
}
.theme-toggle:hover{background:var(--bg-elevated);transform:scale(1.05)}

/* --- Sidebar --- */
.sidebar{
  position:fixed;top:0;left:0;bottom:0;z-index:900;
  width:var(--sidebar-w);
  background:var(--bg-sidebar);
  border-right:1px solid var(--border);
  display:flex;flex-direction:column;
  transform:translateX(-100%);
  transition:transform 0.25s cubic-bezier(0.4,0,0.2,1);
  overflow:hidden;
}
.sidebar.open{transform:translateX(0)}
.sidebar-header{
  display:flex;align-items:center;justify-content:space-between;
  padding:16px 20px;border-bottom:1px solid var(--border);
}
.sidebar-header h2{font-size:1.1rem;font-weight:700;color:var(--accent)}
.sidebar-stats{
  display:grid;grid-template-columns:1fr 1fr;
  gap:8px;padding:12px 16px;
  border-bottom:1px solid var(--border);
}
.stat-item{
  display:flex;flex-direction:column;align-items:center;
  font-size:0.7rem;text-transform:uppercase;letter-spacing:0.5px;
  color:var(--text-secondary);padding:6px 4px;
  border-radius:var(--radius-sm);background:var(--bg);
}
.stat-item.correct .stat-val{color:var(--success)}
.stat-item.incorrect .stat-val{color:var(--danger)}
.stat-val{font-size:1.3rem;font-weight:700;color:var(--text);line-height:1.2}
.progress-bar{
  margin:0 16px 4px;height:4px;background:var(--border);
  border-radius:2px;overflow:hidden;
}
.progress-fill{
  height:100%;background:var(--accent);
  border-radius:2px;transition:width 0.3s ease;
  width:0%;
}
.sidebar-filters{
  display:grid;grid-template-columns:1fr 1fr;gap:6px;padding:12px 16px;
  border-bottom:1px solid var(--border);
}
.filter-btn{
  padding:8px 6px;border:none;border-radius:var(--radius-sm);
  background:transparent;color:var(--text-secondary);
  font-size:0.75rem;font-weight:600;cursor:pointer;
  transition:all var(--transition);
  text-transform:none;letter-spacing:0;
  line-height:1.2;white-space:normal;text-align:center;
}
.filter-btn:hover{background:var(--bg-elevated)}
.filter-btn.active{background:var(--accent);color:#fff}
.question-list{
  flex:1;overflow-y:auto;padding:8px 12px;
}
.question-list::-webkit-scrollbar{width:4px}
.question-list::-webkit-scrollbar-thumb{background:var(--border);border-radius:2px}
.q-item{
  display:flex;align-items:center;gap:8px;padding:8px 12px;
  border-radius:var(--radius-sm);cursor:pointer;
  font-size:0.85rem;font-weight:500;
  transition:all 0.15s ease;margin-bottom:2px;
  color:var(--text-secondary);
}
.q-item:hover{background:var(--bg-elevated);color:var(--text)}
.q-item.active{background:var(--accent-light);color:var(--accent);font-weight:600}
.q-item.done-correct{color:var(--success);border-left:3px solid var(--success)}
.q-item.done-incorrect{color:var(--danger);border-left:3px solid var(--danger)}
.q-dot{width:8px;height:8px;border-radius:50%;flex-shrink:0;
  background:var(--text-muted)}
.q-item.done-correct .q-dot{background:var(--success)}
.q-item.done-incorrect .q-dot{background:var(--danger)}

/* --- Sidebar Sync Panel --- */
.sidebar-sync{
  padding:12px 16px;border-top:1px solid var(--border);
  background:var(--bg);
}

/* --- Main --- */
.main{
  margin-left:0;padding-top:var(--topbar-h);
  min-height:100vh;
  transition:margin-left 0.25s cubic-bezier(0.4,0,0.2,1);
}
.sidebar.open ~ .main{margin-left:var(--sidebar-w)}

/* --- Top Bar --- */
.topbar{
  position:fixed;top:0;left:0;right:0;z-index:800;
  height:var(--topbar-h);
  background:var(--bg-card);border-bottom:1px solid var(--border);
  display:flex;align-items:center;gap:12px;padding:0 16px;
  box-shadow:var(--shadow);
}
.sidebar.open ~ .topbar{left:var(--sidebar-w)}

.icon-btn{
  width:36px;height:36px;border:none;border-radius:var(--radius-sm);
  background:transparent;color:var(--text-secondary);
  font-size:1.1rem;cursor:pointer;
  display:flex;align-items:center;justify-content:center;
  transition:all var(--transition);
}
.icon-btn:hover{background:var(--bg-elevated);color:var(--text)}

.search-box{
  flex:1;max-width:400px;
}
.search-box input{
  width:100%;padding:8px 14px;
  border:1px solid var(--border);border-radius:20px;
  background:var(--bg-input);color:var(--text);
  font-size:0.85rem;outline:none;
  transition:border-color var(--transition);
}
.search-box input:focus{border-color:var(--border-focus)}
.search-box input::placeholder{color:var(--text-muted)}

.topbar-actions{
  display:flex;align-items:center;gap:8px;margin-left:auto;
}
/* --- Timer --- */
.timer-display{
  font-family:var(--font-mono);font-size:0.9rem;
  font-weight:600;color:var(--text-secondary);
  min-width:50px;text-align:center;
}
.timer-display.hidden{display:none}

/* --- Buttons --- */
.btn{
  padding:8px 16px;border:none;border-radius:var(--radius-sm);
  font-size:0.85rem;font-weight:600;cursor:pointer;
  background:var(--bg-elevated);color:var(--text);
  transition:all var(--transition);
  white-space:nowrap;
}
.btn:hover{background:var(--border);transform:translateY(-1px)}
.btn:active{transform:translateY(0)}
.btn:disabled{opacity:0.4;cursor:not-allowed;transform:none}
.btn-danger{background:var(--danger);color:#fff}
.btn-danger:hover{background:#dc2626}
.btn-accent{background:var(--accent);color:#fff}
.btn-accent:hover{background:var(--accent-hover)}

/* --- Quiz Container --- */
.quiz-container{
  max-width:780px;margin:0 auto;padding:24px 20px 80px;
}
.quiz-card{
  background:var(--bg-card);border:1px solid var(--border);
  border-radius:var(--radius);padding:28px;
  box-shadow:var(--shadow);
  animation:fadeIn 0.3s ease;
}
@keyframes fadeIn{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}
.quiz-header{
  display:flex;align-items:center;gap:12px;margin-bottom:20px;
}
.quiz-num{
  font-size:0.8rem;font-weight:700;text-transform:uppercase;
  letter-spacing:1px;color:var(--accent);
  background:var(--accent-light);padding:4px 12px;
  border-radius:20px;
}
.quiz-question{
  font-size:1.1rem;font-weight:500;line-height:1.7;
  margin-bottom:24px;color:var(--text);
}
.quiz-options{display:flex;flex-direction:column;gap:10px}

.quiz-actions{
  display:flex;gap:10px;margin-top:16px;flex-wrap:wrap;
}

.opt-btn{
  display:flex;align-items:center;gap:14px;
  width:100%;padding:14px 18px;
  border:2px solid var(--border);border-radius:var(--radius-sm);
  background:var(--bg);color:var(--text);
  font-size:0.95rem;text-align:left;cursor:pointer;
  transition:all 0.15s ease;
}
.opt-btn:hover{border-color:var(--accent);background:var(--accent-light)}
.opt-btn:active{transform:scale(0.995)}
.opt-label{
  width:30px;height:30px;border-radius:50%;
  background:var(--bg-elevated);color:var(--text-secondary);
  display:flex;align-items:center;justify-content:center;
  font-weight:700;font-size:0.85rem;flex-shrink:0;
  border:2px solid var(--border);
}
.opt-btn.selected{border-color:var(--accent);background:var(--accent-light)}
.opt-btn.selected .opt-label{background:var(--accent);color:#fff;border-color:var(--accent)}
.opt-btn.correct{border-color:var(--success);background:var(--success-bg)}
.opt-btn.correct .opt-label{background:var(--success);color:#fff;border-color:var(--success)}
.opt-btn.incorrect{border-color:var(--danger);background:var(--danger-bg)}
.opt-btn.incorrect .opt-label{background:var(--danger);color:#fff;border-color:var(--danger)}
.opt-btn.reveal-correct{border-color:var(--success);background:var(--success-bg)}
.opt-btn.reveal-correct .opt-label{background:var(--success);color:#fff;border-color:var(--success)}
.opt-btn.disabled{pointer-events:none;opacity:0.7}

/* --- Feedback --- */
.quiz-feedback{margin-top:20px;padding:14px 18px;border-radius:var(--radius-sm);display:none}
.quiz-feedback.show{display:block;animation:fadeIn 0.3s ease}
.quiz-feedback.correct-fb{background:var(--success-bg);border:1px solid var(--success);color:var(--success)}
.feedback-text{font-weight:600;margin-bottom:6px}
.feedback-actions{display:flex;gap:8px;margin-top:12px;flex-wrap:wrap}

/* --- Navigation --- */
.quiz-nav{
  display:flex;align-items:center;justify-content:space-between;
  margin-top:24px;gap:12px;
}
.jump-box{display:flex;align-items:center;gap:6px}
.jump-box input{
  width:70px;padding:8px 10px;
  border:1px solid var(--border);border-radius:var(--radius-sm);
  background:var(--bg-input);color:var(--text);
  font-size:0.85rem;text-align:center;outline:none;
}
.jump-box input:focus{border-color:var(--border-focus)}
.jump-box input::placeholder{color:var(--text-muted);font-size:0.7rem}

/* --- Review Container --- */
.review-container{padding:24px;max-width:800px;margin:0 auto}
.review-container.hidden{display:none}
.review-container h2{font-size:1.3rem;margin-bottom:20px;color:var(--accent)}
.review-item{
  background:var(--bg-card);border:1px solid var(--border);
  border-radius:var(--radius);padding:20px;margin-bottom:16px;
}
.review-item .q-text{font-weight:600;margin-bottom:10px}
.review-item .q-answer{font-size:0.9rem;margin-top:8px}
.review-item .q-answer span{font-weight:600}
.review-item.correct-item{border-left:4px solid var(--success)}
.review-item.incorrect-item{border-left:4px solid var(--danger)}

/* --- Modal --- */
.modal{
  position:fixed;inset:0;z-index:2000;
  background:rgba(0,0,0,0.6);
  display:flex;align-items:center;justify-content:center;
  backdrop-filter:blur(4px);
}
.modal.hidden{display:none}
.modal-content{
  background:var(--bg-card);border:1px solid var(--border);
  border-radius:var(--radius);padding:28px;
  max-width:420px;width:90%;
  box-shadow:var(--shadow-lg);
  animation:modalIn 0.2s ease;
}
@keyframes modalIn{from{opacity:0;transform:scale(0.95)}to{opacity:1;transform:scale(1)}}
.modal-content h3{font-size:1.1rem;margin-bottom:12px}
.modal-content p{color:var(--text-secondary);font-size:0.9rem;margin-bottom:20px}
.modal-actions{display:flex;gap:10px;justify-content:flex-end}

.modal-wide{max-width:700px!important}
.modal-header{display:flex;align-items:center;justify-content:space-between;margin-bottom:12px}
.modal-header h3{margin-bottom:0!important}

.textbook-meta{display:flex;gap:16px;margin-bottom:14px;font-size:0.8rem;color:var(--text-muted)}
.textbook-excerpt{
  background:var(--bg);border:1px solid var(--border);
  border-radius:var(--radius-sm);padding:18px;
  max-height:400px;overflow-y:auto;
  font-size:0.9rem;line-height:1.7;
  color:var(--text);margin-bottom:16px;
}
.textbook-excerpt p{margin-bottom:0;color:var(--text)!important}

/* --- Empty / Loading States --- */
.empty-state{
  text-align:center;padding:60px 20px;color:var(--text-muted);
}
.empty-state .icon{font-size:3rem;margin-bottom:16px}
.empty-state h3{font-size:1.1rem;margin-bottom:8px;color:var(--text-secondary)}
.empty-state p{font-size:0.9rem}

/* --- Responsive --- */
@media(max-width:768px){
  :root{--sidebar-w:300px}
  .quiz-container{padding:12px 8px 80px;max-width:100%}
  .quiz-card{padding:14px 12px}
  .quiz-header{flex-wrap:wrap;gap:6px;margin-bottom:12px}
  .quiz-num{font-size:0.7rem;padding:3px 8px}
  .quiz-question{font-size:0.95rem;line-height:1.6;margin-bottom:16px}
  .opt-btn{padding:11px 12px;font-size:0.85rem;gap:10px}
  .opt-label{width:26px;height:26px;font-size:0.75rem}
  .quiz-nav{flex-wrap:wrap;justify-content:center;gap:8px;margin-top:16px}
  .quiz-actions{gap:6px}
  .quiz-actions .btn{font-size:0.7rem;padding:6px 8px}
  .feedback-actions{gap:6px}
  .feedback-actions .btn{font-size:0.7rem;padding:5px 7px}
  .search-box{display:none}
  .topbar{justify-content:space-between;gap:4px;padding:0 6px;flex-wrap:nowrap;overflow-x:auto}
  .topbar-actions{gap:3px}
  .topbar-actions .btn{font-size:0.65rem;padding:5px 6px}
  .topbar-actions .icon-btn{font-size:0.85rem;padding:4px}
  #reset-btn{padding:5px 7px;font-size:0.65rem}
  .jump-box input{width:55px;padding:6px;font-size:0.75rem}
  .jump-box .btn{padding:6px 8px;font-size:0.75rem}
  .sidebar-stats{grid-template-columns:repeat(3,1fr);gap:6px;padding:10px}
  .stat-item{padding:6px 4px;font-size:0.6rem}
  .stat-val{font-size:1.1rem}
  .modal-content{padding:16px 14px;width:95%}
  .modal-wide{max-width:95%!important}
  .textbook-offset-setting{flex-wrap:wrap;font-size:0.75rem}
  .search-phrase-box{font-size:0.8rem}
  .bookmark-btn{font-size:1rem}
}
@media(min-width:1024px){
  .sidebar{transform:translateX(0)}
  .main{margin-left:var(--sidebar-w)}
  .topbar{left:var(--sidebar-w)}
  #sidebar-toggle{display:none}
  #sidebar-close{display:none}
}

/* --- Toast --- */
.toast-container{
  position:fixed;bottom:24px;right:24px;z-index:3000;
  display:flex;flex-direction:column;gap:8px;
  pointer-events:none;
}
.toast{
  background:var(--bg-card);border:1px solid var(--border);
  border-radius:var(--radius-sm);padding:12px 18px;
  font-size:0.85rem;color:var(--text);
  box-shadow:var(--shadow-lg);
  animation:toastIn 0.3s ease, toastOut 0.3s ease 2.5s forwards;
  max-width:360px;pointer-events:auto;
}
@keyframes toastIn{from{opacity:0;transform:translateX(40px)}to{opacity:1;transform:translateX(0)}}
@keyframes toastOut{from{opacity:1}to{opacity:0;transform:translateY(-10px)}}

/* --- Scrollbar --- */
::-webkit-scrollbar{width:6px}
::-webkit-scrollbar-track{background:transparent}
::-webkit-scrollbar-thumb{background:var(--border);border-radius:3px}
::-webkit-scrollbar-thumb:hover{background:var(--text-muted)}

/* --- Custom Features Styling --- */
.bookmark-btn {
  background: transparent;
  border: none;
  font-size: 1.2rem;
  cursor: pointer;
  opacity: 0.35;
  transition: opacity 0.2s, transform 0.2s;
  padding: 2px 4px;
}
.bookmark-btn:hover {
  opacity: 0.8;
  transform: scale(1.15);
}
.bookmark-btn.active {
  opacity: 1;
  color: #f1c40f;
  transform: scale(1.1);
}

.retry-filter-btn {
  background: rgba(231, 76, 60, 0.1) !important;
  border-color: rgba(231, 76, 60, 0.3) !important;
  color: var(--danger) !important;
  font-weight: 600;
}
.retry-filter-btn:hover, .retry-filter-btn.active {
  background: var(--danger) !important;
  color: #fff !important;
}

.btn-outline {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-secondary);
}
.btn-outline:hover {
  background: var(--bg-hover);
  color: var(--text);
  border-color: var(--accent);
}

/* --- Multi-select & Unsolved --- */
.opt-btn.multi-select::before {
  content: "";
  display: inline-block;
  width: 16px;
  height: 16px;
  margin-right: 10px;
  border: 2px solid var(--border);
  border-radius: 3px;
  vertical-align: middle;
  transition: all var(--transition);
  flex-shrink: 0;
}

.opt-btn.multi-select.selected::before {
  background-color: var(--accent);
  border-color: var(--accent);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='white' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='20 6 9 17 4 12'%3E%3C/polyline%3E%3C/svg%3E");
  background-size: 80%;
  background-position: center;
  background-repeat: no-repeat;
}

.opt-btn.multi-select.reveal-correct::before {
  border-color: var(--success);
}
.opt-btn.multi-select.correct::before {
  background-color: var(--success);
  border-color: var(--success);
}
.opt-btn.multi-select.incorrect::before {
  background-color: var(--danger);
  border-color: var(--danger);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='white' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'%3E%3Cline x1='18' y1='6' x2='6' y2='18'%3E%3C/line%3E%3Cline x1='6' y1='6' x2='18' y2='18'%3E%3C/line%3E%3C/svg%3E");
}

.submit-multi-btn {
  display: block;
  width: 100%;
  padding: 12px;
  margin-top: 16px;
  background: var(--accent);
  color: white;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition);
}
.submit-multi-btn:hover {
  background: var(--accent-hover);
}
.submit-multi-btn:disabled {
  background: var(--border);
  color: var(--text-muted);
  cursor: not-allowed;
}

.badge-multi-select {
  display: inline-block;
  padding: 4px 8px;
  background: var(--accent-light);
  color: var(--accent);
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  font-weight: 600;
  margin-left: 10px;
}

.badge-unsolved {
  display: inline-block;
  padding: 4px 8px;
  background: var(--warning);
  color: #fff;
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  font-weight: 600;
  margin-left: 10px;
}
.stat-item.unsolved .stat-val { color: var(--warning); }
.q-item.done-unsolved { color: var(--warning); border-left: 3px solid var(--warning); }
.q-item.done-unsolved .q-dot { background: var(--warning); }

/* --- Glossary --- */
.glossary-term {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 16px;
  margin-bottom: 8px;
  animation: fadeIn 0.2s ease;
}
.glossary-term-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 8px;
}
.glossary-term-name {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--accent);
}
.glossary-topic-badge {
  font-size: 0.7rem;
  padding: 4px 8px;
  background: var(--bg-hover);
  border-radius: 20px;
  color: var(--text-secondary);
  border: 1px solid var(--border);
}
.glossary-definition {
  font-size: 0.95rem;
  line-height: 1.6;
  color: var(--text);
  margin-bottom: 12px;
}
.glossary-meta {
  font-size: 0.8rem;
  color: var(--text-muted);
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.glossary-meta-item strong {
  color: var(--text-secondary);
}
.glossary-highlight {
  background: var(--accent-light);
  color: var(--accent);
  padding: 0 4px;
  border-radius: 3px;
  cursor: help;
  border-bottom: 1px dashed var(--accent);
}

/* Textbook PDF Offset & Search Styles */
.textbook-offset-setting {
  margin-top: 15px;
  padding-top: 15px;
  border-top: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.85rem;
  color: var(--text-muted);
}
.textbook-offset-setting input {
  padding: 4px 8px;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--surface);
  color: var(--text);
  font-size: 0.9rem;
}
.textbook-search-hint {
  margin: 10px 0;
  padding: 10px 15px;
  background-color: rgba(46, 204, 113, 0.1);
  border-left: 4px solid var(--success, #2ecc71);
  border-radius: 4px;
  display: flex;
  align-items: center;
  gap: 10px;
  animation: fadeIn 0.3s ease;
}
.search-hint-icon {
  font-size: 1.2rem;
}
.search-hint-text kbd {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 3px;
  padding: 2px 6px;
  font-size: 0.8em;
  font-family: monospace;
}
.search-phrase-box {
  margin-top: 15px;
  padding: 10px;
  background: var(--bg);
  border: 1px dashed var(--border);
  border-radius: 4px;
  font-size: 0.9rem;
}
.search-phrase-box code {
  background: var(--surface);
  padding: 2px 6px;
  border-radius: 4px;
  color: var(--accent);
}

/* In-App HTML Textbook Reader Styles */
.textbook-reader {
  margin-top: 15px;
  padding: 15px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  max-height: 50vh;
  overflow-y: auto;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  line-height: 1.6;
  font-size: 0.95rem;
  color: var(--text);
  white-space: pre-wrap; /* Preserve basic formatting */
}
.highlight-pulse {
  background-color: rgba(245, 158, 11, 0.4);
  border: 2px solid var(--warning);
  border-radius: 4px;
  padding: 2px 4px;
  animation: pulseHighlight 2s infinite;
  display: inline;
}
@keyframes pulseHighlight {
  0% { background-color: rgba(245, 158, 11, 0.4); box-shadow: 0 0 0 0 rgba(245, 158, 11, 0.7); }
  50% { background-color: rgba(245, 158, 11, 0.8); box-shadow: 0 0 10px 5px rgba(245, 158, 11, 0.2); }
  100% { background-color: rgba(245, 158, 11, 0.4); box-shadow: 0 0 0 0 rgba(245, 158, 11, 0); }
}

/* Modal Pulsing Highlight Animation */
mark.modal-pulse-highlight {
  background-color: rgba(233, 69, 96, 0.25);
  color: inherit;
  padding: 2px 6px;
  border-radius: 4px;
  border: 1px solid rgba(233, 69, 96, 0.7);
  animation: modalPulse 1.5s ease-in-out infinite alternate;
  display: inline;
}

@keyframes modalPulse {
  0% {
    background-color: rgba(233, 69, 96, 0.2);
    border-color: rgba(233, 69, 96, 0.5);
    box-shadow: 0 0 4px rgba(233, 69, 96, 0.2);
  }
  100% {
    background-color: rgba(255, 215, 0, 0.45);
    border-color: rgba(255, 215, 0, 0.9);
    box-shadow: 0 0 12px rgba(255, 215, 0, 0.6);
  }
}

/* Embedded Split PDF Modal */
.textbook-modal-content {
  max-width: 1100px !important;
  width: 95% !important;
  max-height: 90vh;
  display: flex;
  flex-direction: column;
}
.textbook-split-container {
  display: flex;
  gap: 16px;
  flex: 1;
  min-height: 520px;
  max-height: 70vh;
}
.textbook-left-panel {
  flex: 1;
  max-width: 380px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  overflow-y: auto;
}
.textbook-right-panel {
  flex: 2;
  display: flex;
  background: #000;
  border-radius: var(--radius-sm);
  overflow: hidden;
  border: 1px solid var(--border);
}
.textbook-iframe {
  width: 100%;
  height: 100%;
  border: none;
  background: white;
}
.textbook-panel-actions {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: auto;
}

@media (max-width: 768px) {
  .textbook-split-container {
    flex-direction: column;
    max-height: 80vh;
  }
  .textbook-left-panel {
    max-width: 100%;
  }
  .textbook-right-panel {
    min-height: 350px;
  }
}