/* ==========================================================================
   ScoreChem.in — Complete Unified 3-Column Layout Engine
   Shared by all Syllabus Hubs, Chapter Notes, and Arena Pages
   ========================================================================== */

:root {
  --radius-orig: 12px;
  --radius-sm-orig: 6px;
  --radius-full-orig: 9999px;
  --container-wide: 1440px;

  /* Editorial Palette Tokens */
  --paper: #F5F6F1;
  --paper-alt: #EDEFE7;
  --ink: #14213D;
  --ink-soft: #2A3550;
  --graphite: #5B6472;
  --line: rgba(20, 33, 61, 0.16);
  --violet: #6E3FA3;
  --violet-dim: #6E3FA31a;
  --flame: #E2622A;
  --flame-dim: #E2622A1a;
  --green: #3F7D58;

  /* Universal Fallbacks */
  --bg: var(--paper);
  --surface: var(--paper);
  --surface-subtle: var(--paper-alt);
  --surface-elevated: #ffffff;
  --text: var(--ink);
  --text-secondary: var(--ink-soft);
  --text-muted: var(--graphite);
  --border: var(--line);
  --primary: var(--violet);
  --primary-light: var(--violet-dim);
  --cta: var(--flame);
  --cta-hover: #c94e1c;
  --accent-green: var(--green);
  --error: #c4264f;

  --font-display: "Literata", Georgia, serif;
  --font-body: "IBM Plex Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-data: "IBM Plex Mono", ui-monospace, Menlo, monospace;
}

/* ---------------- 1. Sticky Navigation & Switcher ---------------- */
header.top-nav {
  position: sticky;
  top: 0;
  background: rgba(245, 246, 241, 0.94);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1.5px solid var(--line);
  z-index: 100;
  padding: 0.85rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.brand {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--ink);
  text-decoration: none;
  font-family: var(--font-display);
}
.brand span { color: var(--violet); }

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.exam-selector-wrapper {
  background: var(--paper);
  border-bottom: 1.5px solid var(--line);
  padding: 0.75rem 1.5rem;
}

.exam-selector-inner {
  max-width: var(--container-wide);
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  overflow-x: auto;
  white-space: nowrap;
}

.exam-pill-btn {
  background: var(--paper-alt);
  border: 1.5px solid var(--line);
  color: var(--graphite);
  padding: 0.4rem 1.1rem;
  border-radius: var(--radius-full-orig);
  font-size: 0.82rem;
  font-family: var(--font-body);
  font-weight: 600;
  cursor: pointer;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  transition: all 0.15s ease;
}

.exam-pill-btn:hover {
  border-color: var(--violet);
  color: var(--violet);
}

.exam-pill-btn.active {
  background: var(--violet);
  color: #ffffff;
  border-color: var(--violet);
}

/* ---------------- 2. 3-Column Layout ---------------- */
.app-layout,
.notes-layout {
  display: grid !important;
  grid-template-columns: 310px minmax(0, 1fr) 290px !important;
  gap: 1.75rem !important;
  max-width: var(--container-wide) !important;
  margin: 0 auto !important;
  padding: 1.5rem 1.25rem 4rem !important;
  align-items: start !important;
}

.col-left,
.col-right,
.chapter-toc-card,
.facts-rail {
  position: sticky !important;
  top: 5rem !important;
  max-height: calc(100vh - 6.5rem) !important;
  overflow-y: auto !important;
  background: var(--paper) !important;
  border: 1.5px solid var(--line) !important;
  border-radius: var(--radius-orig) !important;
  padding: 1.25rem !important;
  box-shadow: 0 1px 3px rgba(20, 33, 61, 0.04) !important;
}

.col-left::-webkit-scrollbar,
.col-right::-webkit-scrollbar,
.chapter-toc-card::-webkit-scrollbar,
.facts-rail::-webkit-scrollbar {
  width: 4px;
}

.col-left::-webkit-scrollbar-thumb,
.col-right::-webkit-scrollbar-thumb,
.chapter-toc-card::-webkit-scrollbar-thumb,
.facts-rail::-webkit-scrollbar-thumb {
  background: var(--line);
  border-radius: 2px;
}

.col-center,
.notes-body-card {
  background: var(--paper) !important;
  border: 1.5px solid var(--line) !important;
  border-radius: var(--radius-orig) !important;
  padding: 2.25rem !important;
  min-height: calc(100vh - 6.5rem) !important;
  box-shadow: 0 1px 3px rgba(20, 33, 61, 0.04) !important;
}

/* ---------------- 3. Left Rail: Unit Topic List & Chapter TOC ---------------- */
ul.nav-topic-list,
ul.toc-list {
  list-style: none !important;
  list-style-type: none !important;
  margin: 0 !important;
  padding: 0 !important;
  display: flex !important;
  flex-direction: column !important;
  gap: 0.35rem !important;
}

ul.nav-topic-list li,
ul.toc-list li {
  list-style: none !important;
  list-style-type: none !important;
  margin: 0 !important;
  padding: 0 !important;
}

/* Base interactive button/link styling */
.nav-topic-btn,
ul.toc-list a {
  width: 100% !important;
  box-sizing: border-box !important;
  text-align: left !important;
  background: transparent !important;
  border: 1.5px solid transparent !important;
  padding: 0.6rem 0.8rem !important;
  font-family: var(--font-body) !important;
  font-size: 0.88rem !important;
  color: var(--ink-soft) !important;
  border-radius: 8px !important;
  cursor: pointer !important;
  line-height: 1.35 !important;
  text-decoration: none !important;
  display: flex !important;
  justify-content: space-between !important;
  align-items: center !important;
  transition: all 0.15s ease !important;
}

.nav-topic-btn:hover,
ul.toc-list a:hover {
  background: var(--paper-alt) !important;
  color: var(--violet) !important;
}

/* Active Highlighted State */
.nav-topic-btn.active,
ul.toc-list a.active,
ul.toc-list li.active a {
  background: #FFFFFF !important;
  color: #1A56DB !important;
  border-color: #1A56DB !important;
  font-weight: 600 !important;
  box-shadow: 0 2px 6px rgba(26, 86, 219, 0.08) !important;
}

/* Chapter TOC Card Header */
.toc-title {
  font-family: var(--font-data, monospace) !important;
  font-size: 0.78rem !important;
  font-weight: 700 !important;
  text-transform: uppercase !important;
  letter-spacing: 0.05em !important;
  color: var(--graphite) !important;
  margin-bottom: 0.85rem !important;
  display: flex !important;
  align-items: center !important;
  gap: 6px !important;
}

/* ---------------- 4. Center Column Components ---------------- */
.breadcrumbs {
  font-family: var(--font-data) !important;
  font-size: 0.82rem !important;
  color: var(--graphite) !important;
  margin-bottom: 1rem !important;
}

.breadcrumbs a {
  color: var(--ink) !important;
  text-decoration: none;
}

.flashcard-badge {
  display: inline-block !important;
  font-family: var(--font-data) !important;
  font-size: 0.75rem !important;
  font-weight: 600 !important;
  padding: 3px 8px !important;
  border-radius: var(--radius-sm-orig) !important;
  background: var(--violet-dim) !important;
  color: var(--violet) !important;
}

.unit-meta-bar {
  display: flex !important;
  flex-wrap: wrap !important;
  gap: 1.25rem !important;
  padding: 0.75rem 1rem !important;
  background: var(--paper-alt) !important;
  border-radius: var(--radius-sm-orig) !important;
  border: 1px solid var(--line) !important;
  font-size: 0.88rem !important;
}

.syllabus-box {
  background: var(--paper) !important;
  border: 1.5px solid var(--line) !important;
  border-radius: var(--radius-orig) !important;
  padding: 1.5rem !important;
  margin: 1.25rem 0 !important;
}

.action-row {
  margin-top: 2rem !important;
  padding: 1.25rem 0 !important;
  border-top: 1.5px solid var(--line) !important;
  border-bottom: 1.5px solid var(--line) !important;
  display: flex !important;
  justify-content: space-between !important;
  align-items: center !important;
  flex-wrap: wrap !important;
  gap: 1rem !important;
}

.btn-cta,
.btn-cta-orig,
.guide-btn-cta {
  background: var(--flame) !important;
  color: #ffffff !important;
  padding: 0.65rem 1.6rem !important;
  border-radius: var(--radius-full-orig) !important;
  text-decoration: none !important;
  font-weight: 600 !important;
  font-size: 0.92rem !important;
  display: inline-flex !important;
  align-items: center !important;
  gap: 8px !important;
  border: 1.5px solid transparent !important;
  transition: all 0.15s ease !important;
  box-shadow: 0 2px 6px rgba(226, 98, 42, 0.25) !important;
}

.btn-cta:hover,
.btn-cta-orig:hover,
.guide-btn-cta:hover {
  background: #c94e1c !important;
  transform: translateY(-1px) !important;
}

/* ---------------- 5. 10-PYQ Interactive Arena ---------------- */
.pyq-arena {
  margin-top: 2rem !important;
  scroll-margin-top: 6rem !important;
  border: 1.5px solid var(--line) !important;
  border-radius: var(--radius-orig) !important;
  background: var(--paper) !important;
  overflow: hidden !important;
}

.pyq-header {
  background: var(--paper-alt) !important;
  padding: 0.85rem 1.25rem !important;
  border-bottom: 1.5px solid var(--line) !important;
  display: flex !important;
  justify-content: space-between !important;
  align-items: center !important;
}

.pyq-tag {
  font-family: var(--font-data) !important;
  font-size: 0.75rem !important;
  font-weight: 600 !important;
  padding: 3px 8px !important;
  border-radius: var(--radius-sm-orig) !important;
  background: var(--violet-dim) !important;
  color: var(--violet) !important;
}

.pyq-body {
  padding: 1.5rem !important;
}

.pyq-question {
  font-family: var(--font-body) !important;
  font-size: 1.05rem !important;
  line-height: 1.6 !important;
  color: var(--ink) !important;
  margin-bottom: 1.25rem !important;
}

.pyq-action-bar {
  padding: 1rem 0 0.5rem !important;
  border-top: 1.5px dashed var(--line) !important;
  display: flex !important;
  gap: 0.6rem !important;
  align-items: center !important;
  flex-wrap: wrap !important;
}

.pyq-solution-drawer {
  margin-top: 1rem !important;
  border-top: 1.5px solid var(--line) !important;
  padding-top: 0.75rem !important;
}

.pyq-solution-drawer summary {
  font-family: var(--font-body) !important;
  font-size: 0.88rem !important;
  font-weight: 600 !important;
  color: var(--violet) !important;
  cursor: pointer !important;
  user-select: none !important;
}

.pyq-solution-content {
  margin-top: 0.75rem !important;
  padding: 1.25rem !important;
  background: var(--paper-alt) !important;
  border: 1.5px solid var(--line) !important;
  border-radius: var(--radius-sm-orig) !important;
  font-size: 0.92rem !important;
  line-height: 1.6 !important;
  color: var(--ink-soft) !important;
}

.flashcard-trap {
  background: rgba(226, 98, 42, 0.08) !important;
  border-left: 4px solid var(--flame) !important;
  padding: 0.85rem 1rem !important;
  border-radius: 4px !important;
  margin-top: 0.75rem !important;
  font-size: 0.88rem !important;
}

/* ---------------- 6. Right Rail Widgets & PYQ Grid ---------------- */
.widget-box,
.fact-card {
  background: var(--paper-alt) !important;
  border: 1.5px solid var(--line) !important;
  border-radius: var(--radius-orig) !important;
  padding: 1.2rem !important;
  margin-bottom: 1.25rem !important;
}

.widget-title,
.fact-card-title {
  font-family: var(--font-data) !important;
  font-size: 0.8rem !important;
  font-weight: 600 !important;
  text-transform: uppercase !important;
  letter-spacing: 0.04em !important;
  color: var(--ink) !important;
  margin-bottom: 0.75rem !important;
  display: flex !important;
  align-items: center !important;
  gap: 6px !important;
}

.stat-callout {
  font-family: var(--font-display) !important;
  font-size: 1.35rem !important;
  font-weight: 700 !important;
  color: var(--violet) !important;
  margin: 0.25rem 0 0.45rem !important;
}

.pyq-grid {
  display: grid !important;
  grid-template-columns: repeat(5, 1fr) !important;
  gap: 0.45rem !important;
  margin-top: 0.65rem !important;
}

.pyq-badge {
  display: flex !important;
  align-items: center !important;
  justify-content: center !important;
  background: var(--paper) !important;
  border: 1.5px solid var(--line) !important;
  border-radius: var(--radius-sm-orig) !important;
  height: 38px !important;
  font-family: var(--font-data) !important;
  font-size: 0.82rem !important;
  font-weight: 600 !important;
  color: var(--ink-soft) !important;
  cursor: pointer !important;
  transition: all 0.15s ease !important;
  user-select: none !important;
}

.pyq-badge:hover {
  border-color: var(--violet) !important;
  color: var(--violet) !important;
}

.pyq-badge.active {
  background: var(--violet) !important;
  color: #ffffff !important;
  border-color: var(--violet) !important;
}

.pyq-badge.done:not(.active) {
  border-color: var(--accent-green) !important;
  color: var(--accent-green) !important;
}

.pyq-marks-badge {
  display: inline-flex !important;
  align-items: center !important;
  justify-content: center !important;
  padding: 3px 10px !important;
  border-radius: 9999px !important;
  font-family: var(--font-data) !important;
  font-size: 0.72rem !important;
  font-weight: 700 !important;
  letter-spacing: 0.02em !important;
  background: #F1F5F9 !important;
  color: #475569 !important;
  border: 1px solid #E2E8F0 !important;
}

.pyq-marks-badge.marks-1 {
  background: #EFF6FF !important;
  color: #2563EB !important;
  border-color: #BFDBFE !important;
}

.pyq-marks-badge.marks-2 {
  background: #F0FDF4 !important;
  color: #16A34A !important;
  border-color: #BBF7D0 !important;
}

.pyq-marks-badge.marks-3 {
  background: #FFF7ED !important;
  color: #D97706 !important;
  border-color: #FED7AA !important;
}

.pyq-marks-badge.marks-5 {
  background: #FEF2F2 !important;
  color: #DC2626 !important;
  border-color: #FECACA !important;
}

/* ---------------- 7. Topic Section Pagination & Controls ---------------- */
.topic-section {
  display: none;
  animation: fadeInTopic 0.18s ease-in-out;
}

.topic-section.active-section {
  display: block !important;
}

@keyframes fadeInTopic {
  from { opacity: 0; transform: translateY(3px); }
  to { opacity: 1; transform: translateY(0); }
}

.topic-pagination-bar {
  display: flex !important;
  flex-direction: row !important;
  justify-content: space-between !important;
  align-items: center !important;
  margin-top: 3rem !important;
  padding-top: 1.5rem !important;
  border-top: 1.5px solid var(--line) !important;
  gap: 1rem !important;
}

/* Enforce compact pill sizing so neither button stretches */
.topic-pagination-bar .btn {
  display: inline-flex !important;
  align-items: center !important;
  justify-content: center !important;
  width: auto !important;
  min-width: 140px !important;
  max-width: fit-content !important;
  padding: 0.55rem 1.4rem !important;
  border-radius: var(--radius-full-orig, 9999px) !important;
  font-family: var(--font-body) !important;
  font-size: 0.88rem !important;
  font-weight: 600 !important;
  cursor: pointer !important;
  text-decoration: none !important;
  box-sizing: border-box !important;
}

.topic-pagination-bar #prev-topic-btn {
  background: transparent !important;
  border: 1.5px solid var(--line) !important;
  color: var(--ink-soft) !important;
}

.topic-pagination-bar #prev-topic-btn:hover {
  border-color: var(--violet) !important;
  color: var(--violet) !important;
  background: var(--paper-alt) !important;
}

.topic-pagination-bar #next-topic-btn {
  background: var(--violet) !important;
  border: 1.5px solid var(--violet) !important;
  color: #ffffff !important;
}

.topic-pagination-bar #next-topic-btn:hover {
  background: #593186 !important;
  border-color: #593186 !important;
}

/* ---------------- 8. Interactive Charts, Diagrams & Molecule Containers ---------------- */
.chart-box-container,
.molecule-viewer-box {
  background: #FFFFFF !important;
  border: 1.5px solid var(--line) !important;
  border-radius: var(--radius-orig) !important;
  padding: 1.25rem !important;
  margin: 1.5rem 0 !important;
  box-shadow: 0 2px 8px rgba(20, 33, 61, 0.04) !important;
  position: relative !important;
  overflow: hidden !important;
}

.chart-caption,
.viewer-caption {
  font-family: var(--font-data, monospace) !important;
  font-size: 0.78rem !important;
  color: var(--graphite) !important;
  text-align: center !important;
  margin-top: 0.75rem !important;
  line-height: 1.4 !important;
}

/* Inline Vector SVG Diagram Cards */
.chem-diagram-card {
  margin: 1.75rem 0 !important;
  padding: 1.5rem !important;
  background: #FFFFFF !important;
  border: 1.5px solid var(--line) !important;
  border-radius: var(--radius-orig) !important;
  box-shadow: 0 2px 8px rgba(20, 33, 61, 0.04) !important;
  text-align: center !important;
  overflow-x: auto !important;
}

.chem-diagram-card svg {
  max-width: 100% !important;
  height: auto !important;
  display: block !important;
  margin: 0 auto !important;
}

.chem-diagram-card .diagram-caption {
  margin-top: 0.85rem !important;
  font-family: var(--font-data, monospace) !important;
  font-size: 0.82rem !important;
  font-weight: 600 !important;
  color: var(--graphite) !important;
  line-height: 1.4 !important;
}

/* Multi-diagram side-by-side row */
.diagram-row-2col {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 1.5rem;
  flex-wrap: wrap;
}
.diagram-col {
  flex: 1 1 260px;
  max-width: 320px;
}

/* ---------------- 9. Ad Callout & Responsive Breakpoints ---------------- */
.superprofile-footer-ad {
  background: var(--paper-alt) !important;
  border: 1.5px solid var(--line) !important;
  border-radius: var(--radius-orig) !important;
  padding: 2.25rem !important;
  text-align: center !important;
  margin: 2.5rem auto 1.5rem !important;
  max-width: var(--container-wide) !important;
}

.ad-badge {
  font-family: var(--font-data) !important;
  font-size: 0.75rem !important;
  font-weight: 600 !important;
  text-transform: uppercase !important;
  color: var(--violet) !important;
}

.ad-title {
  font-size: 1.5rem !important;
  margin: 0.5rem 0 !important;
}

.ad-desc {
  color: var(--ink-soft) !important;
  max-width: 65ch !important;
  margin: 0 auto 1.5rem !important;
  font-size: 0.95rem !important;
}

@media (max-width: 1150px) {
  .app-layout, .notes-layout {
    grid-template-columns: 280px minmax(0, 1fr) !important;
  }
  .col-right, .facts-rail { display: none !important; }
}

@media (max-width: 850px) {
  .app-layout, .notes-layout {
    grid-template-columns: 1fr !important;
    padding: 1rem !important;
  }
  .col-left, .chapter-toc-card {
    position: static !important;
    max-height: 380px !important;
    margin-bottom: 1.25rem !important;
  }
}

/* =========================================================
   Reading Flow & Line Measure Optimization
   ========================================================= */

/* 1. Set optimal line measure (65–75 characters) and vertical rhythm */
.notes-body-card {
  line-height: 1.7;
}

.notes-body-card p,
.notes-body-card ul,
.notes-body-card ol {
  text-align: left;
  line-height: 1.75;
  color: var(--ink-soft, #2A3550);
  max-width: 72ch;
  margin-bottom: 1.25rem;
}

/* 2. Proportional spacing for the mentor dialogue box */
.notes-body-card div[style*="border-left"] {
  max-width: 74ch;
  margin-top: 1.25rem;
  margin-bottom: 2.25rem !important;
}

.notes-body-card div[style*="border-left"] p {
  line-height: 1.75 !important;
  font-size: 1rem;
}

/* 3. Section subheadings and breathing room */
.notes-body-card h2 {
  margin-top: 2rem;
  margin-bottom: 0.85rem;
  line-height: 1.25;
}

.notes-body-card h3 {
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
  font-size: 1.2rem;
  color: var(--ink, #14213D);
}

/* 4. List readability with inline chemical math */
.notes-body-card li {
  line-height: 1.7;
  margin-bottom: 0.65rem;
}