/* styles.css */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Outfit:wght@300;400;500;600;700;800&family=Playfair+Display:ital,wght@0,400;0,600;0,700;1,400&family=JetBrains+Mono:wght@400;500;600&display=swap');

/* Color Variables & Base Theme (Dark Theme Only) */
:root {
  --bg-app: #050b14; /* Deep dark navy space */
  --bg-book: #0e1626; /* Sleek slate-navy page background */
  --bg-book-dark: #121c2f; /* Highlighted block background */
  --text-primary: #ffffff; /* Bright crisp white */
  --text-secondary: #e2e8f0; /* Soft, highly legible off-white */
  --text-muted: #94a3b8; /* Slate 400 for subtext */
  
  --accent-primary: #fbbf24; /* Warm Gold Amber 400 */
  --accent-primary-hover: #d97706; /* Amber 600 */
  --accent-secondary: #2dd4bf; /* Teal 400 */
  --border-paper: #1e293b; /* Slate 800 border */
  --shadow-color: rgba(0, 0, 0, 0.4);

  --heading-color: #fbbf24; /* Golden headings */
  
  /* Blockquotes */
  --bg-blockquote-tip: #1a160d; /* Warm dark gold tint */
  --text-blockquote-tip: #fde68a; /* Gold 200 */
  --border-blockquote-tip: #d97706;
  
  --bg-blockquote-warn: #221212; /* Dark red tint */
  --text-blockquote-warn: #fecaca; /* Red 200 */
  --border-blockquote-warn: #f87171;

  /* Tables */
  --bg-table-header: #1e293b;
  --bg-table-cell: #0b111e;
  --bg-table-stripe: #0f172a;
  --border-table: #1e293b;

  --font-sans: 'Inter', sans-serif;
  --font-display: 'Outfit', sans-serif;
  --font-serif: 'Playfair Display', serif;
  --font-mono: 'JetBrains Mono', monospace;

  /* Premium single page reading dimensions */
  --book-width: 740px;
  --book-height: 760px;
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-app);
  color: var(--text-primary);
  overflow: hidden;
  height: 100vh;
  display: flex;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}
::-webkit-scrollbar-track {
  background: transparent;
}
::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.1);
  border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
  background: rgba(255, 255, 255, 0.2);
}

.page-content-scroll::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.15);
}
.page-content-scroll::-webkit-scrollbar-thumb:hover {
  background: rgba(255, 255, 255, 0.25);
}

/* Glassmorphic Sidebar */
#sidebar {
  width: 320px;
  height: 100vh;
  background: rgba(10, 17, 30, 0.8);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-right: 1px solid rgba(255, 255, 255, 0.08);
  display: flex;
  flex-direction: column;
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1), width 0.3s;
  z-index: 50;
  flex-shrink: 0;
}

#sidebar.collapsed {
  transform: translateX(-100%);
  position: absolute;
}

.sidebar-header {
  padding: 1.5rem 1.5rem 1rem 1.5rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.sidebar-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: -0.025em;
  background: linear-gradient(135deg, #fbbf24 0%, #d97706 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.sidebar-content {
  flex-grow: 1;
  overflow-y: auto;
  padding: 1rem;
}

.nav-item {
  display: block;
  width: 100%;
  text-align: left;
  padding: 0.65rem 0.85rem;
  margin-bottom: 0.25rem;
  border-radius: 8px;
  color: #94a3b8;
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
  border: none;
  background: transparent;
}

.nav-item:hover {
  background: rgba(255, 255, 255, 0.03);
  color: #f1f5f9;
}

.nav-item.active {
  background: rgba(251, 191, 36, 0.12);
  color: #fbbf24;
  border-left: 3px solid #d97706;
  border-top-left-radius: 0;
  border-bottom-left-radius: 0;
  padding-left: 0.65rem;
}

.nav-chapter-title {
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: #64748b;
  margin-top: 1rem;
  margin-bottom: 0.5rem;
  padding-left: 0.5rem;
}

/* App Main Container */
#main-viewport {
  flex-grow: 1;
  height: 100vh;
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
  align-items: center;
  justify-content: center;
}

.app-header {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 60px;
  padding: 0 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  background: rgba(10, 17, 30, 0.4);
  z-index: 40;
}

.header-button {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.08);
  color: #cbd5e1;
  padding: 0.5rem 1rem;
  border-radius: 8px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
  font-weight: 500;
  transition: all 0.2s;
}

.header-button:hover {
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
}

/* Reading Viewport */
.book-viewport {
  width: 100%;
  height: calc(100vh - 120px);
  margin-top: 40px;
  display: flex;
  justify-content: center;
  align-items: center;
}

/* Centered Reading Column */
.book-container {
  width: var(--book-width);
  height: var(--book-height);
  position: relative;
  box-shadow: 
    0 25px 60px rgba(0, 0, 0, 0.6),
    0 10px 20px rgba(0, 0, 0, 0.4);
  border-radius: 12px;
  background: var(--bg-book);
  transition: width 0.3s, height 0.3s;
  border: 1px solid rgba(255, 255, 255, 0.05);
  overflow: hidden;
}

/* Reading Page Wrapper */
.page-wrapper {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: var(--bg-book);
  overflow: hidden;
}

.page-texture {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: 
    radial-gradient(var(--bg-book-dark) 40%, transparent 80%),
    linear-gradient(rgba(255,255,255,0.005) 1px, transparent 1px);
  background-size: 100% 100%, 20px 20px;
  pointer-events: none;
  opacity: 0.2;
  z-index: 15;
}

.page-content-scroll {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  padding: 4rem 3.5rem;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  color: var(--text-secondary);
  z-index: 5;
}

.page-header-text {
  position: absolute;
  top: 1.25rem;
  left: 3.5rem;
  right: 3.5rem;
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text-muted);
  display: flex;
  justify-content: space-between;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  padding-bottom: 0.5rem;
  z-index: 20;
}

.page-footer-number {
  position: absolute;
  bottom: 1.25rem;
  left: 3.5rem;
  right: 3.5rem;
  font-family: var(--font-display);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-muted);
  display: flex;
  justify-content: space-between;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding-top: 0.5rem;
  z-index: 20;
}

/* Typography & Layout Clarity Updates */
.page-content-scroll h1 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 2.25rem;
  line-height: 1.2;
  letter-spacing: -0.04em;
  color: var(--accent-primary);
  margin-top: 1rem;
  margin-bottom: 1.5rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  padding-bottom: 0.5rem;
}

.page-content-scroll h2 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.4rem;
  line-height: 1.3;
  letter-spacing: -0.02em;
  color: var(--accent-primary);
  margin-top: 2rem;
  margin-bottom: 0.85rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.page-content-scroll h3 {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.15rem;
  color: var(--accent-secondary);
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
}

.page-content-scroll p {
  font-size: 1.05rem; /* Large, crisp text */
  line-height: 1.8; /* Generous spacing for reading comfort */
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
}

.page-content-scroll strong {
  font-weight: 700;
  color: var(--text-primary);
}

.page-content-scroll ul {
  list-style-type: none;
  margin-bottom: 1.5rem;
  padding-left: 0.25rem;
}

.page-content-scroll li {
  position: relative;
  padding-left: 1.5rem;
  margin-bottom: 0.75rem;
  font-size: 1.025rem;
  line-height: 1.65;
  color: var(--text-secondary);
}

.page-content-scroll li::before {
  content: "•";
  position: absolute;
  left: 0.5rem;
  color: var(--accent-primary);
  font-weight: bold;
  font-size: 1.1rem;
  top: -0.1rem;
}

/* Callout Styling (High-contrast blocks) */
.page-content-scroll blockquote {
  border-left: 4px solid var(--border-blockquote-tip);
  background: var(--bg-blockquote-tip);
  padding: 1.25rem 1.5rem;
  margin: 1.75rem 0;
  border-radius: 0 12px 12px 0;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
  transition: all 0.25s;
}

.page-content-scroll blockquote.tip {
  border-left-color: var(--border-blockquote-tip);
  background: var(--bg-blockquote-tip);
}

.page-content-scroll blockquote.warning {
  border-left-color: var(--border-blockquote-warn);
  background: var(--bg-blockquote-warn);
}

.page-content-scroll blockquote p {
  font-size: 0.95rem;
  line-height: 1.65;
  color: var(--text-blockquote-tip);
  margin-bottom: 0;
}

.page-content-scroll blockquote.warning p {
  color: var(--text-blockquote-warn);
}

.blockquote-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--border-blockquote-tip);
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.blockquote-title.warning-title {
  color: var(--border-blockquote-warn);
}

/* Tables (Highly Legible In Dark Mode) */
.page-content-scroll table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  margin: 1.75rem 0;
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid var(--border-table);
}

.page-content-scroll th {
  background: var(--bg-table-header);
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-primary);
  padding: 0.85rem 1.1rem;
  text-align: left;
  border-bottom: 1px solid var(--border-table);
}

.page-content-scroll td {
  padding: 0.85rem 1.1rem;
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
  border-bottom: 1px solid var(--border-table);
  background: var(--bg-table-cell);
}

.page-content-scroll tr:last-child td {
  border-bottom: none;
}

.page-content-scroll tr:nth-child(even) td {
  background: var(--bg-table-stripe);
}

/* Mermaid SVG Dark Styling */
.mermaid-container {
  background: rgba(15, 23, 42, 0.4);
  border: 1px solid var(--border-table);
  border-radius: 12px;
  padding: 1.25rem;
  margin: 1.75rem 0;
  overflow-x: auto;
  display: flex;
  justify-content: center;
}

.mermaid svg {
  filter: saturate(1.1) brightness(0.95);
}
.mermaid .node rect, 
.mermaid rect.actor {
  fill: #1e293b !important;
  stroke: #475569 !important;
}
.mermaid .node .label,
.mermaid text.actor {
  color: #f8fafc !important;
  fill: #f8fafc !important;
}
.mermaid .edgePath .path {
  stroke: #94a3b8 !important;
}
.mermaid .edgeLabel rect {
  fill: #0f172a !important;
}
.mermaid .edgeLabel span,
.mermaid .messageText {
  color: #cbd5e1 !important;
  fill: #cbd5e1 !important;
}
.mermaid .marker {
  fill: #94a3b8 !important;
  stroke: #94a3b8 !important;
}

/* Interactive cover style */
.cover-layout {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  text-align: center;
  padding: 3rem 2rem;
  background: radial-gradient(circle at center, #111d33 0%, #050b14 100%);
  color: var(--text-primary);
  border-radius: 8px;
  position: relative;
  overflow: hidden;
}

.cover-layout::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: 
    radial-gradient(circle at 20% 30%, rgba(251, 191, 36, 0.08) 0%, transparent 50%),
    radial-gradient(circle at 80% 70%, rgba(45, 212, 191, 0.08) 0%, transparent 50%);
  z-index: 1;
  pointer-events: none;
}

.cover-content {
  z-index: 2;
}

.cover-tagline {
  font-family: var(--font-display);
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: #fbbf24;
  margin-bottom: 1rem;
}

.cover-title {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 2.5rem;
  line-height: 1.1;
  letter-spacing: -0.04em;
  color: #ffffff;
  margin-bottom: 1.25rem;
  border-bottom: none !important;
}

.cover-subtitle {
  font-family: var(--font-serif);
  font-style: italic;
  font-size: 1.25rem;
  color: #94a3b8;
  max-width: 420px;
  margin: 0 auto 2rem auto;
  line-height: 1.4;
}

.cover-badge {
  display: inline-flex;
  align-items: center;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.1);
  padding: 0.5rem 1.25rem;
  border-radius: 9999px;
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 600;
  color: #fbbf24;
  gap: 0.5rem;
}

.cover-footer {
  z-index: 2;
  font-size: 0.8rem;
  color: #64748b;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  width: 80%;
  padding-top: 1.5rem;
}

/* TOC (Table of Contents) Layout */
.toc-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
  margin-top: 1.5rem;
}

.toc-item {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  padding: 0.85rem 1.1rem;
  border-radius: 8px;
  border: 1px solid var(--border-table);
  background: rgba(255, 255, 255, 0.02);
  transition: all 0.2s;
  cursor: pointer;
}

.toc-item:hover {
  background: rgba(255, 255, 255, 0.05);
  border-color: var(--accent-primary);
  transform: translateY(-1px);
}

.toc-number {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.1rem;
  color: var(--accent-primary);
  line-height: 1;
}

.toc-info {
  flex-grow: 1;
}

.toc-chapter-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--text-primary);
}

.toc-page {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-muted);
}

/* Embedded illustrations container */
.illustration-box {
  background: rgba(15, 23, 42, 0.3);
  border: 1px dashed var(--border-paper);
  border-radius: 12px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
  margin: 1.5rem 0;
  min-height: 180px;
}

.illustration-box img {
  max-width: 100%;
  max-height: 160px;
  border-radius: 8px;
  box-shadow: 0 4px 15px rgba(0,0,0,0.3);
}

.illustration-box span {
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 0.05em;
  margin-top: 0.75rem;
}

/* Bottom Control bar */
#control-bar {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 60px;
  padding: 0 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  background: rgba(10, 17, 30, 0.6);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  z-index: 40;
}

.progress-container {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-grow: 1;
  max-width: 400px;
  margin: 0 2rem;
}

.progress-track {
  height: 4px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 2px;
  flex-grow: 1;
  position: relative;
  cursor: pointer;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, #fbbf24, #d97706);
  border-radius: 2px;
  width: 0%;
  transition: width 0.1s;
}

.progress-text {
  font-family: var(--font-display);
  font-size: 0.8rem;
  font-weight: 600;
  color: #cbd5e1;
  min-width: 60px;
}

.control-buttons {
  display: flex;
  gap: 0.75rem;
}

.control-btn {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.08);
  color: #cbd5e1;
  width: 38px;
  height: 38px;
  border-radius: 8px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s;
}

.control-btn:hover:not(:disabled) {
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
  transform: translateY(-1px);
}

.control-btn:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

.control-btn svg {
  width: 18px;
  height: 18px;
}

/* Quick Wins Checklist Box */
.checklist-box {
  background: rgba(22, 101, 34, 0.1); /* Translucent Green */
  border: 1px solid rgba(34, 197, 94, 0.3); /* Green 500 border */
  border-radius: 12px;
  padding: 1.25rem;
  margin: 1.75rem 0;
}

.checklist-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.95rem;
  color: #4ade80; /* Green 400 */
  margin-bottom: 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.checklist-items {
  list-style: none !important;
  padding-left: 0 !important;
  margin-bottom: 0 !important;
}

.checklist-items li {
  position: relative;
  padding-left: 1.5rem !important;
  margin-bottom: 0.5rem !important;
  font-size: 0.85rem !important;
  color: #cbd5e1 !important;
}

.checklist-items li::before {
  content: "✓" !important;
  color: #4ade80 !important;
  font-weight: bold;
  left: 0.25rem !important;
  font-size: 0.9rem !important;
}

/* Code theme overrides for inline code */
code {
  font-family: var(--font-mono);
  background: rgba(255, 255, 255, 0.08);
  color: #fde68a; /* Amber-200 */
  padding: 0.15rem 0.35rem;
  border-radius: 4px;
  font-size: 0.85em;
  border: 1px solid rgba(255, 255, 255, 0.03);
}

/* Mobile responsive adjustments */
@media (max-width: 1024px) {
  :root {
    --book-width: 90%;
    --book-height: 80vh;
  }
}

@media (max-width: 768px) {
  body {
    flex-direction: column;
    overflow-y: auto;
    height: auto;
  }

  #sidebar {
    position: fixed;
    top: 60px;
    left: 0;
    width: 280px;
    height: calc(100vh - 60px);
    transform: translateX(-100%);
  }

  #sidebar.active-mobile {
    transform: translateX(0);
  }

  #main-viewport {
    width: 100%;
    height: 100vh;
    padding-top: 60px;
  }

  .book-viewport {
    height: calc(100vh - 120px);
    margin-top: 0;
    padding: 1rem;
  }

  .book-container {
    width: 100% !important;
    height: 100% !important;
    box-shadow: none;
    border-radius: 12px;
    background: var(--bg-book);
    border: none;
  }

  .page-content-scroll {
    padding: 3rem 1.5rem;
  }

  .page-header-text {
    left: 1.5rem;
    right: 1.5rem;
  }

  .page-footer-number {
    left: 1.5rem;
    right: 1.5rem;
  }

  .progress-container {
    margin: 0 0.5rem;
  }
  
  .progress-text {
    display: none;
  }
}