:root {
  --bg-primary: #ffffff;
  --bg-secondary: #f7f8f8;
  --bg-tertiary: #eff0f0;
  --text-primary: #212225;
  --text-secondary: #53575b;
  --text-tertiary: #878a8c;
  --accent-color: #006184;
  --accent-hover: #004d69;
  --accent-light: #e6f3f7;
  --link-color: #157493;
  --border-color: #e0e2e2;
  --border-strong: #bdc0c0;
  --note-highlight-bg: #fff8e1;
  --note-highlight-border: #fbc02d;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --font-serif: "Ensign:Serif", "Noto Serif", Georgia, Cambria, "Times New Roman", Times, serif;
  --font-sans: "Ensign:Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --content-max-width: 740px;
  --reader-font-size: 1.125rem;
  --reader-line-height: 1.75;
  --sidebar-width: 380px;
  --header-height: 60px;
  --transition-speed: 0.25s;
}

[data-theme="dark"] {
  --bg-primary: #121212;
  --bg-secondary: #1e1e1e;
  --bg-tertiary: #2a2a2a;
  --text-primary: #e6e6e6;
  --text-secondary: #a9adad;
  --text-tertiary: #75797a;
  --accent-color: #49cce6;
  --accent-hover: #7de3f4;
  --accent-light: #163640;
  --link-color: #49cce6;
  --border-color: #333333;
  --border-strong: #444444;
  --note-highlight-bg: #332d18;
  --note-highlight-border: #e6b800;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.4);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.5);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.6);
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.5;
  transition: background-color var(--transition-speed) ease, color var(--transition-speed) ease;
  overflow-x: hidden;
}

/* App Header */
.app-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-height);
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.5rem;
}

.header-left, .header-right {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--accent-color);
  text-decoration: none;
  cursor: pointer;
}

.brand svg {
  width: 24px;
  height: 24px;
}

.talk-selector {
  padding: 0.4rem 0.75rem;
  font-size: 0.9rem;
  font-family: var(--font-sans);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  background: var(--bg-secondary);
  color: var(--text-primary);
  cursor: pointer;
  max-width: 260px;
  text-overflow: ellipsis;
  outline: none;
}

.talk-selector:focus {
  border-color: var(--accent-color);
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.45rem 0.85rem;
  font-size: 0.875rem;
  font-weight: 500;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition-speed) ease;
  font-family: var(--font-sans);
  background: transparent;
  color: var(--text-primary);
}

.btn:hover {
  background: var(--bg-secondary);
}

.btn-primary {
  background: var(--accent-color);
  color: #ffffff;
}

.btn-primary:hover {
  background: var(--accent-hover);
  color: #ffffff;
}

.btn-icon {
  padding: 0.45rem;
  border-radius: 50%;
  width: 36px;
  height: 36px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.notes-toggle-badge {
  background: var(--accent-color);
  color: white;
  font-size: 0.75rem;
  padding: 0.15rem 0.45rem;
  border-radius: 12px;
  margin-left: 0.3rem;
  font-weight: 600;
}

/* Layout container */
.main-layout {
  display: flex;
  min-height: calc(100vh - var(--header-height));
  position: relative;
  transition: padding-right var(--transition-speed) ease;
}

.reader-container {
  flex: 1;
  max-width: 100%;
  padding: 2.5rem 1.5rem 6rem;
  display: flex;
  justify-content: center;
  transition: margin-right var(--transition-speed) ease;
}

.article-content {
  width: 100%;
  max-width: var(--content-max-width);
}

/* Breadcrumbs & Header Meta */
.talk-meta {
  margin-bottom: 2rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 1.5rem;
}

.session-badge {
  display: inline-block;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: 600;
  color: var(--accent-color);
  margin-bottom: 0.5rem;
}

.talk-title {
  font-family: var(--font-serif);
  font-size: 2.4rem;
  line-height: 1.25;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
}

.talk-speaker {
  font-family: var(--font-sans);
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.talk-role {
  font-size: 0.95rem;
  color: var(--text-tertiary);
  margin-top: 0.2rem;
}

.talk-summary-box {
  margin-top: 1.25rem;
  padding: 1rem 1.25rem;
  background: var(--bg-secondary);
  border-left: 4px solid var(--accent-color);
  border-radius: var(--radius-sm);
  font-size: 1rem;
  font-style: italic;
  color: var(--text-secondary);
}

/* Talk Body */
.talk-body {
  font-family: var(--font-serif);
  font-size: var(--reader-font-size);
  line-height: var(--reader-line-height);
  color: var(--text-primary);
}

.talk-body p {
  margin-bottom: 1.4rem;
  text-align: justify;
  text-justify: inter-word;
  position: relative;
  transition: background-color 0.3s ease;
  border-radius: var(--radius-sm);
  padding: 2px 4px;
}

.talk-body p.highlight-active-para {
  background-color: var(--note-highlight-bg);
}

.talk-body h2, .talk-body h3 {
  font-family: var(--font-sans);
  margin: 2rem 0 1rem;
  color: var(--text-primary);
  font-weight: 600;
}

.talk-body blockquote {
  border-left: 3px solid var(--accent-color);
  margin: 1.5rem 0;
  padding-left: 1.25rem;
  font-style: italic;
  color: var(--text-secondary);
}

/* Notation Markers */
.note-ref {
  background: none;
  border: none;
  cursor: pointer;
  padding: 0 2px;
  margin: 0 1px;
  vertical-align: baseline;
  display: inline-block;
  outline: none;
}

.note-ref .marker {
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--accent-color);
  background-color: var(--accent-light);
  padding: 1px 5px;
  border-radius: 4px;
  transition: all 0.2s ease;
  line-height: 1;
}

.note-ref:hover .marker,
.note-ref:focus .marker {
  background-color: var(--accent-color);
  color: #ffffff;
  transform: translateY(-2px);
}

.note-ref.active-marker .marker {
  background-color: var(--note-highlight-border);
  color: #121212;
  box-shadow: 0 0 0 2px var(--note-highlight-border);
}

/* Side Notes Panel */
.sidebar-panel {
  position: fixed;
  top: var(--header-height);
  right: 0;
  bottom: 0;
  width: var(--sidebar-width);
  background: var(--bg-secondary);
  border-left: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-md);
  transform: translateX(100%);
  transition: transform var(--transition-speed) cubic-bezier(0.16, 1, 0.3, 1);
  z-index: 90;
}

.sidebar-panel.open {
  transform: translateX(0);
}

.sidebar-header {
  padding: 1rem 1.25rem;
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.sidebar-title {
  font-size: 1rem;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-primary);
}

.sidebar-content {
  flex: 1;
  overflow-y: auto;
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.note-card {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 0.9rem 1rem;
  transition: all 0.25s ease;
  cursor: pointer;
  position: relative;
}

.note-card:hover {
  border-color: var(--accent-color);
  box-shadow: var(--shadow-sm);
}

.note-card.active-note {
  background-color: var(--note-highlight-bg);
  border-color: var(--note-highlight-border);
  box-shadow: 0 0 0 2px var(--note-highlight-border);
}

.note-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.4rem;
}

.note-badge {
  font-size: 0.75rem;
  font-weight: 700;
  background: var(--accent-light);
  color: var(--accent-color);
  padding: 2px 6px;
  border-radius: 4px;
}

.note-card.active-note .note-badge {
  background: var(--note-highlight-border);
  color: #121212;
}

.note-jump-btn {
  background: none;
  border: none;
  color: var(--link-color);
  font-size: 0.75rem;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 2px;
}

.note-jump-btn:hover {
  text-decoration: underline;
}

.note-card-body {
  font-size: 0.925rem;
  line-height: 1.45;
  color: var(--text-primary);
}

.note-card-body a {
  color: var(--link-color);
  text-decoration: none;
}

.note-card-body a:hover {
  text-decoration: underline;
}

/* In-text Endnotes Section at bottom */
.endnotes-section {
  margin-top: 3.5rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
}

.endnotes-title {
  font-family: var(--font-sans);
  font-size: 1.3rem;
  margin-bottom: 1.25rem;
}

.endnotes-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.endnotes-item {
  display: flex;
  gap: 0.75rem;
  font-size: 0.95rem;
  line-height: 1.5;
}

.endnotes-marker {
  font-weight: 700;
  color: var(--accent-color);
  cursor: pointer;
}

.endnotes-marker:hover {
  text-decoration: underline;
}

.source-link {
  display: inline-block;
  margin-top: 0.75rem;
  font-size: 0.9rem;
  color: var(--link-color);
  text-decoration: none;
}

.source-link:hover {
  text-decoration: underline;
}

/* Talk Library (index page) */
.library-title {
  font-family: var(--font-serif);
  font-size: 2.2rem;
  margin-bottom: 0.5rem;
}

.library-subtitle {
  color: var(--text-secondary);
  margin-bottom: 2rem;
}

.talk-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.talk-card {
  display: block;
  padding: 1.25rem 1.5rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background: var(--bg-primary);
  color: inherit;
  text-decoration: none;
  transition: all var(--transition-speed) ease;
}

.talk-card:hover,
.talk-card:focus-visible {
  border-color: var(--accent-color);
  box-shadow: var(--shadow-sm);
}

.talk-card-title {
  font-family: var(--font-serif);
  font-size: 1.35rem;
  font-weight: 700;
  margin: 0.25rem 0;
}

.talk-card-speaker {
  font-weight: 600;
  color: var(--text-secondary);
}

.talk-card-summary {
  margin-top: 0.5rem;
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.talk-card-notes {
  margin-top: 0.6rem;
  font-size: 0.8rem;
  color: var(--text-tertiary);
}

/* Responsive */
@media (min-width: 1200px) {
  body.sidebar-open .main-layout {
    padding-right: var(--sidebar-width);
  }
}

@media (max-width: 900px) {
  .app-header {
    padding: 0 1rem;
  }
  .talk-title {
    font-size: 1.8rem;
  }
  .sidebar-panel {
    width: 100%;
    max-width: 450px;
  }
}

@media (max-width: 600px) {
  .header-actions-text {
    display: none;
  }
  .talk-selector {
    max-width: 140px;
  }
  .sidebar-panel {
    max-width: 100%;
  }
}