/* =========================================================
   dotnetacademy — site design system: "Aurora night"
   Deep ink-navy pages, soft multicolor aurora glows at the top,
   glassy translucent surfaces, and five accent colors that give
   every category its own identity.
   Built on top of Metronic (dark mode). Keep page-level styles
   here, not in per-page <style> blocks.
   ========================================================= */

:root {
  /* Surfaces */
  --dna-bg: #0b1020;
  --dna-bg-raised: #111833;
  --dna-code-bg: #070b18;
  --dna-code-border: rgba(255, 255, 255, 0.1);
  --dna-glass: rgba(255, 255, 255, 0.04);
  --dna-glass-hover: rgba(255, 255, 255, 0.075);
  --dna-line: rgba(255, 255, 255, 0.09);
  --dna-line-strong: rgba(255, 255, 255, 0.18);

  /* Text */
  --dna-ink: #f4f6ff;
  --dna-body: #cdd4e6;
  --dna-muted: #94a0ba;
  --dna-faint: #66728f;

  /* Aurora accents */
  --aurora-violet: #7c5cff;
  --aurora-cyan: #22d3ee;
  --aurora-magenta: #f472b6;
  --aurora-lime: #a3e635;
  --aurora-orange: #ff8a1f;

  /* Interaction */
  --dna-link: #67e8f9;
  --dna-primary: #9a80ff;
  --dna-primary-ring: rgba(34, 211, 238, 0.35);
  --dna-gradient: linear-gradient(100deg, #9a80ff 0%, #22d3ee 100%);
  --dna-success: #4ade80;

  --dna-radius: 1rem;
  --dna-radius-sm: 0.625rem;
  --dna-header-h: 72px;

  --dna-font-ui: 'Sora', 'Segoe UI', system-ui, sans-serif;
  --dna-font-prose: 'IBM Plex Sans', 'Segoe UI', system-ui, sans-serif;
  --dna-font-mono: 'JetBrains Mono', 'Cascadia Code', 'Fira Code', Consolas, Monaco, monospace;
}

/* Metronic forces html { font-size: 13px !important } (12px on phones), which shrinks every
   rem-based size on the site. html:root outranks it so rem means 16px again. */
html:root {
  font-size: 16px !important;
}

.home-title,
.page-title,
.lesson-title {
  text-wrap: balance;
}

html {
  height: 100%;
  margin: 0;
  padding: 0;
  scroll-behavior: smooth;
  color-scheme: dark;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

body {
  position: relative;
  min-height: 100%;
  margin: 0 !important;
  padding: 0 !important;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  font-family: var(--dna-font-ui);
  color: var(--dna-body);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body,
#kt_body {
  background-image: none !important;
  background-color: var(--dna-bg) !important;
}

.page,
.wrapper,
.content {
  position: relative;
  z-index: 1;
  background-image: none !important;
  background-color: transparent !important;
}

/* Aurora glow behind the top of every page */
body::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 1100px;
  z-index: 0;
  pointer-events: none;
  background:
    radial-gradient(42vw 30rem at 6% -6%, rgba(124, 92, 255, 0.5), transparent 70%),
    radial-gradient(36vw 26rem at 94% 2%, rgba(34, 211, 238, 0.34), transparent 70%),
    radial-gradient(30vw 22rem at 42% 34%, rgba(244, 114, 182, 0.14), transparent 72%);
}

body:has(.lesson-layout)::before {
  opacity: 0.55;
}

button,
input,
select,
textarea,
.btn,
.form-control,
.form-select,
.menu-link {
  font-family: inherit;
}

::selection {
  background: rgba(124, 92, 255, 0.55);
  color: #ffffff;
}

:focus-visible {
  outline: 2px solid var(--aurora-cyan);
  outline-offset: 3px;
}

h1, h2, h3, h4, h5, h6 {
  color: var(--dna-ink);
}

a {
  color: var(--dna-link);
}

/* ---------------------------------------------------------
   Metronic reconciliation (dark)
   --------------------------------------------------------- */
.text-primary,
.text-hover-primary:hover,
.text-active-primary.active {
  color: var(--dna-link) !important;
}

.text-dark,
.text-gray-800,
.text-gray-900 {
  color: var(--dna-ink) !important;
}

.text-muted,
.text-gray-600,
.text-gray-700 {
  color: var(--dna-muted) !important;
}

.bg-light-primary,
.badge-light-primary {
  background-color: rgba(124, 92, 255, 0.2) !important;
  color: #cfc6ff !important;
}

.btn.btn-primary {
  background: var(--dna-gradient);
  border: 0;
  color: #0b1020;
  font-weight: 650;
  border-radius: 999px;
  box-shadow: 0 0 18px rgba(34, 211, 238, 0.32);
  transition: box-shadow 0.2s ease, filter 0.2s ease;
}

.btn.btn-primary:hover,
.btn.btn-primary:focus,
.btn.btn-primary:active {
  background: var(--dna-gradient) !important;
  color: #0b1020 !important;
  filter: brightness(1.08);
  box-shadow: 0 0 26px rgba(34, 211, 238, 0.5);
}

.btn.btn-light {
  background-color: var(--dna-glass);
  border: 1px solid var(--dna-line);
  color: var(--dna-ink);
  font-weight: 600;
  border-radius: 999px;
}

.btn.btn-light:hover,
.btn.btn-light:focus {
  background-color: var(--dna-glass-hover);
  border-color: var(--dna-line-strong);
  color: var(--dna-ink);
}

.btn.btn-light-primary {
  background-color: rgba(124, 92, 255, 0.2);
  border-color: transparent;
  color: #cfc6ff;
  font-weight: 600;
  border-radius: 999px;
}

.btn.btn-light-primary:hover,
.btn.btn-light-primary:focus {
  background-color: rgba(124, 92, 255, 0.4) !important;
  color: #ffffff !important;
}

.form-control,
.form-select {
  background-color: rgba(255, 255, 255, 0.05);
  border-color: var(--dna-line);
  color: var(--dna-ink);
  border-radius: var(--dna-radius-sm);
}

.form-control::placeholder {
  color: #7d89a8;
}

.form-control:focus,
.form-select:focus {
  background-color: rgba(255, 255, 255, 0.08);
  border-color: var(--aurora-cyan);
  box-shadow: 0 0 0 3px var(--dna-primary-ring);
  color: var(--dna-ink);
}

.card,
.dna-card {
  background-color: var(--dna-glass);
  border: 1px solid var(--dna-line) !important;
  border-radius: var(--dna-radius);
  box-shadow: none !important;
}

.scrolltop {
  background-color: var(--dna-bg-raised) !important;
  border: 1px solid var(--dna-line-strong);
  border-radius: 999px;
}

/* ---------------------------------------------------------
   Shared accents: every track picks one of five colors
   --------------------------------------------------------- */
.accent-0 { --accent: var(--aurora-violet);  --accent-text: #b3a3ff; --accent-rgb: 124, 92, 255; }
.accent-1 { --accent: var(--aurora-cyan);    --accent-text: #67e8f9; --accent-rgb: 34, 211, 238; }
.accent-2 { --accent: var(--aurora-magenta); --accent-text: #f9a8d4; --accent-rgb: 244, 114, 182; }
.accent-3 { --accent: var(--aurora-lime);    --accent-text: #bef264; --accent-rgb: 163, 230, 53; }
.accent-4 { --accent: var(--aurora-orange);  --accent-text: #ffb066; --accent-rgb: 255, 138, 31; }

.gradient-text {
  background: linear-gradient(100deg, #22d3ee 0%, #9a80ff 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  -webkit-text-fill-color: transparent;
}

/* ---------------------------------------------------------
   Header
   --------------------------------------------------------- */
#kt_header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(11, 16, 32, 0.78) !important;
  backdrop-filter: blur(14px) saturate(160%);
  -webkit-backdrop-filter: blur(14px) saturate(160%);
  border-bottom: 1px solid var(--dna-line);
  box-shadow: none !important;
}

#kt_header .brand-title {
  font-family: var(--dna-font-ui);
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: #ffffff !important;
}

#kt_header .menu-title,
#kt_header .menu-link {
  font-weight: 500;
  font-size: 0.9rem;
  color: #cbd5e1 !important;
  background: none !important;
  transition: color 0.2s ease, text-shadow 0.2s ease;
}

#kt_header .menu-link:hover .menu-title,
#kt_header .menu-link:focus-visible .menu-title,
#kt_header .menu-link.active .menu-title {
  color: #ffffff !important;
  text-shadow: 0 0 12px rgba(34, 211, 238, 0.55);
}

/* Compact header search */
.header-search {
  position: relative;
}

.header-search .form-control {
  width: 200px;
  padding-left: 2.5rem;
  border-radius: 999px;
  transition: border-color 0.2s ease, box-shadow 0.2s ease, width 0.2s ease;
}

.header-search .form-control:focus {
  width: 250px;
}

.header-search .search-icon {
  position: absolute;
  left: 0.875rem;
  top: 50%;
  transform: translateY(-50%);
  pointer-events: none;
}

#kt_header .search-icon,
#kt_header .search-icon .path1,
#kt_header .search-icon .path2 {
  color: var(--dna-muted) !important;
}

#kt_header_menu_toggle i,
#kt_header_menu_toggle i .path1,
#kt_header_menu_toggle i .path2 {
  color: #cbd5e1 !important;
}

#kt_toolbar {
  display: none !important;
}

/* The logo has an opaque light tile; keep it as a rounded app-icon on dark */
#kt_header img,
#kt_footer img {
  border-radius: 0.55rem;
}

/* ---------------------------------------------------------
   Shared primitives
   --------------------------------------------------------- */
.dna-breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.25rem 0.5rem;
  list-style: none;
  margin: 0;
  padding: 0;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--dna-muted);
  min-width: 0;
}

.dna-breadcrumb li {
  display: inline-flex;
  align-items: center;
  min-width: 0;
}

.dna-breadcrumb li + li::before {
  content: "/";
  margin-right: 0.5rem;
  color: var(--dna-faint);
}

.dna-breadcrumb a {
  color: var(--dna-muted);
  text-decoration: none;
}

.dna-breadcrumb a:hover {
  color: var(--aurora-cyan);
}

.dna-breadcrumb li[aria-current] span {
  color: var(--dna-ink);
  font-weight: 600;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  max-width: 60vw;
}

.dna-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.3rem 0.7rem;
  border-radius: 999px;
  font-size: 0.8rem;
  font-weight: 600;
  line-height: 1.2;
  color: var(--dna-body);
  background-color: var(--dna-glass);
  border: 1px solid var(--dna-line);
  text-decoration: none;
  max-width: 100%;
}

.dna-chip-primary {
  color: #cfc6ff;
  background-color: rgba(124, 92, 255, 0.18);
  border-color: rgba(124, 92, 255, 0.35);
}

.empty-note {
  max-width: 34rem;
  padding: 2.5rem 0;
}

.empty-note h2,
.empty-note h1,
.empty-note h3 {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--dna-ink);
  margin: 0 0 0.5rem;
}

.empty-note p {
  font-family: var(--dna-font-prose);
  font-size: 1.05rem;
  line-height: 1.6;
  color: var(--dna-body);
  margin: 0 0 1.25rem;
}

.text-link {
  font-weight: 600;
  color: var(--dna-link);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.25em;
}

.text-link:hover {
  color: #ffffff;
}

/* Glass surface used by rows and tiles */
.glass {
  background: var(--dna-glass);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid var(--dna-line);
  transition: background-color 0.25s ease, border-color 0.25s ease, transform 0.25s ease;
}

.glass:hover {
  background: var(--dna-glass-hover);
  border-color: var(--dna-line-strong);
  transform: translateY(-2px);
}

/* ---------------------------------------------------------
   Page head (category, search)
   --------------------------------------------------------- */
.page-head {
  padding: 1.5rem 0 2.5rem;
  margin-bottom: 1rem;
}

.page-title {
  font-size: clamp(2.1rem, 1.3rem + 3.4vw, 3.75rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.1;
  color: #ffffff;
  margin: 1.5rem 0 1rem;
  overflow-wrap: anywhere;
}

.page-lead {
  font-family: var(--dna-font-prose);
  font-size: 1.15rem;
  line-height: 1.6;
  color: var(--dna-body);
  max-width: 38rem;
  margin: 0 0 1.5rem;
}

.page-facts {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 0 0 1.5rem;
}

.page-facts span {
  font-family: var(--dna-font-mono);
  font-size: 0.8rem;
  padding: 0.3rem 0.75rem;
  border-radius: 999px;
  color: var(--aurora-cyan);
  background: rgba(34, 211, 238, 0.1);
  border: 1px solid rgba(34, 211, 238, 0.25);
}

.page-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem 1.5rem;
}

/* ---------------------------------------------------------
   Search field (home + search page)
   --------------------------------------------------------- */
.big-search {
  position: relative;
  display: flex;
  align-items: center;
  max-width: 36rem;
  padding: 0.4rem;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--dna-line-strong);
  box-shadow: 0 10px 40px rgba(8, 145, 178, 0.18);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.big-search:focus-within {
  border-color: var(--aurora-cyan);
  box-shadow: 0 0 0 3px var(--dna-primary-ring), 0 10px 40px rgba(8, 145, 178, 0.25);
}

.big-search-icon {
  flex: 0 0 auto;
  margin: 0 0.25rem 0 1.1rem;
  font-size: 1.1rem;
  color: var(--dna-muted);
}

.big-search .form-control {
  flex: 1 1 auto;
  min-width: 0;
  height: 3rem;
  padding: 0 0.75rem;
  font-size: 1rem;
  background: transparent;
  border: 0;
  box-shadow: none;
  color: #ffffff;
}

.big-search .form-control:focus {
  background: transparent;
  box-shadow: none;
}

.big-search .btn {
  flex: 0 0 auto;
  height: 3rem;
  padding: 0 1.75rem;
}

.search-filter {
  margin-top: 1.25rem;
  max-width: 20rem;
}

.search-filter .form-label {
  font-weight: 600;
  color: var(--dna-ink);
}

/* ---------------------------------------------------------
   Home — hero
   --------------------------------------------------------- */
.home-hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 3rem;
  align-items: center;
  padding: 3rem 0 4rem;
}

@media (min-width: 992px) {
  .home-hero {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    gap: 4rem;
    padding: 5rem 0 6rem;
  }
}

.home-title {
  font-size: clamp(2.5rem, 1.4rem + 4.4vw, 4.75rem);
  font-weight: 700;
  letter-spacing: -0.035em;
  line-height: 1.1;
  color: #ffffff;
  margin: 0 0 1.5rem;
}

.home-lead {
  font-family: var(--dna-font-prose);
  font-size: 1.2rem;
  line-height: 1.6;
  color: var(--dna-body);
  max-width: 34rem;
  margin: 0 0 2.25rem;
}

/* Decorative code window */
.code-window {
  position: relative;
  border-radius: 1.1rem;
  background: rgba(7, 11, 24, 0.82);
  border: 1px solid var(--dna-line-strong);
  box-shadow: 0 30px 80px rgba(0, 0, 0, 0.5), 0 0 60px rgba(124, 92, 255, 0.25);
  overflow: hidden;
}

.code-window-bar {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.75rem 1rem;
  background: rgba(255, 255, 255, 0.04);
  border-bottom: 1px solid var(--dna-line);
}

.code-window-bar i {
  width: 0.7rem;
  height: 0.7rem;
  border-radius: 50%;
}

.code-window-bar i:nth-child(1) { background: #fb7185; }
.code-window-bar i:nth-child(2) { background: #fbbf24; }
.code-window-bar i:nth-child(3) { background: #34d399; }

.code-window-bar span {
  margin-left: 0.5rem;
  font-family: var(--dna-font-mono);
  font-size: 0.75rem;
  color: var(--dna-muted);
}

.code-window pre {
  margin: 0;
  padding: 1.5rem;
  overflow-x: auto;
  font-family: var(--dna-font-mono);
  font-size: 0.85rem;
  line-height: 1.85;
  color: #e2e8f0;
  background: none;
}

.code-window .c-kw { color: var(--aurora-magenta); }
.code-window .c-str { color: var(--aurora-lime); }
.code-window .c-fn { color: var(--aurora-cyan); }
.code-window .c-cm { color: #7d89a8; }

/* ---------------------------------------------------------
   Home — catalog of tracks
   --------------------------------------------------------- */
.catalog {
  padding-bottom: 5rem;
  scroll-margin-top: calc(var(--dna-header-h) + 1rem);
}

.section-head {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 2rem;
}

.section-head h2 {
  margin: 0;
  font-size: clamp(1.6rem, 1.2rem + 1.2vw, 2rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: #ffffff;
}

.section-head p {
  margin: 0.4rem 0 0;
  color: var(--dna-muted);
}

.section-tag {
  flex: 0 0 auto;
  font-family: var(--dna-font-mono);
  font-size: 0.8rem;
  padding: 0.3rem 0.8rem;
  border-radius: 999px;
  color: var(--aurora-cyan);
  background: rgba(34, 211, 238, 0.1);
  border: 1px solid rgba(34, 211, 238, 0.25);
}

.catalog-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  grid-auto-flow: dense;
  gap: 1.25rem;
}

@media (min-width: 640px) {
  .catalog-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 992px) {
  .catalog-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1.5rem;
  }
}

.track {
  display: flex;
  flex-direction: column;
  min-height: 11.5rem;
  padding: 1.5rem;
  border-radius: var(--dna-radius);
  text-decoration: none;
  color: var(--dna-body);
}

.track.glass {
  background:
    radial-gradient(130% 100% at 100% 0%, rgba(var(--accent-rgb), 0.2), transparent 62%),
    var(--dna-glass);
  border-color: rgba(var(--accent-rgb), 0.24);
}

.track.glass:hover {
  background:
    radial-gradient(130% 100% at 100% 0%, rgba(var(--accent-rgb), 0.34), transparent 66%),
    var(--dna-glass-hover);
  border-color: rgba(var(--accent-rgb), 0.65);
  box-shadow: 0 12px 40px rgba(var(--accent-rgb), 0.2);
}

.track-featured {
  min-height: 14rem;
}

@media (min-width: 640px) {
  .track-featured {
    grid-column: span 2;
  }
}

.track-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.track-icon {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  border-radius: 0.75rem;
  font-size: 1.15rem;
  color: var(--accent-text);
  background: rgba(var(--accent-rgb), 0.16);
  border: 1px solid rgba(var(--accent-rgb), 0.35);
}

.track-icon .bi {
  color: inherit;
  font-size: 1.15rem;
  line-height: 1;
}

.track-count {
  flex: 0 0 auto;
  font-family: var(--dna-font-mono);
  font-size: 0.75rem;
  padding: 0.25rem 0.7rem;
  border-radius: 999px;
  color: var(--dna-body);
  background: rgba(255, 255, 255, 0.08);
  white-space: nowrap;
}

.track-name {
  margin: 0 0 0.5rem;
  font-size: 1.15rem;
  font-weight: 650;
  letter-spacing: -0.015em;
  line-height: 1.3;
  color: #ffffff;
  overflow-wrap: anywhere;
  transition: color 0.2s ease;
}

.track-featured .track-name {
  font-size: 1.6rem;
}

.track:hover .track-name {
  color: var(--accent-text);
}

.track-topics {
  margin: auto 0 0;
  padding-top: 0.5rem;
  font-size: 0.82rem;
  line-height: 1.55;
  color: var(--dna-muted);
}

/* ---------------------------------------------------------
   Home — latest lessons
   --------------------------------------------------------- */
.latest {
  padding-bottom: 5rem;
}

.latest-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.latest-row {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  padding: 1.1rem 1.25rem;
  border-radius: var(--dna-radius-sm);
  text-decoration: none;
  color: var(--dna-ink);
}

@media (min-width: 768px) {
  .latest-row {
    flex-direction: row;
    align-items: center;
    gap: 1.5rem;
  }
}

.latest-cat {
  flex: 0 0 auto;
  width: fit-content;
  padding: 0.25rem 0.75rem;
  border-radius: 0.5rem;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent-text, #67e8f9);
  background: rgba(var(--accent-rgb, 34, 211, 238), 0.12);
  border: 1px solid rgba(var(--accent-rgb, 34, 211, 238), 0.3);
}

.latest-title {
  flex: 1 1 auto;
  min-width: 0;
  font-size: 1.05rem;
  font-weight: 500;
  line-height: 1.4;
  transition: color 0.2s ease;
}

.latest-row:hover .latest-title {
  color: var(--accent-text, #67e8f9);
}

.latest-date {
  flex: 0 0 auto;
  font-family: var(--dna-font-mono);
  font-size: 0.8rem;
  color: #8b96ad;
}

.latest-arrow {
  display: none;
  flex: 0 0 auto;
  color: var(--dna-faint);
  transition: color 0.2s ease, transform 0.2s ease;
}

@media (min-width: 768px) {
  .latest-arrow {
    display: inline;
  }
}

.latest-row:hover .latest-arrow {
  color: var(--accent-text, #67e8f9);
  transform: translateX(3px);
}

/* ---------------------------------------------------------
   Category page — topics sidebar + lesson sections
   --------------------------------------------------------- */
.category-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2rem;
  align-items: start;
  margin-bottom: 4rem;
}

@media (min-width: 992px) {
  .category-layout {
    grid-template-columns: 16rem minmax(0, 1fr);
    gap: 3rem;
  }
}

.category-sidebar {
  position: sticky;
  top: calc(var(--dna-header-h) + 1.5rem);
  min-width: 0;
}

.category-sidebar-inner {
  max-height: calc(100vh - var(--dna-header-h) - 3rem);
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: #3a4566 transparent;
}

.topic-nav {
  display: flex;
  flex-direction: column;
  gap: 0.125rem;
  margin-top: 0.75rem;
}

.topic-link {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 0.5rem 0.75rem;
  border-radius: 0.6rem;
  color: var(--dna-body);
  font-size: 0.9rem;
  font-weight: 500;
  line-height: 1.35;
  text-decoration: none;
  transition: background-color 0.2s ease, color 0.2s ease;
}

.topic-link:hover {
  background: rgba(34, 211, 238, 0.1);
  color: #ffffff;
}

.topic-link-count {
  flex-shrink: 0;
  font-family: var(--dna-font-mono);
  font-size: 0.75rem;
  color: var(--dna-muted);
}

.topic-section {
  margin-bottom: 3rem;
  scroll-margin-top: calc(var(--dna-header-h) + 1.25rem);
}

.topic-section:last-child {
  margin-bottom: 0;
}

.topic-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--dna-line);
}

.topic-head h2 {
  margin: 0;
  font-size: 1.4rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: #ffffff;
}

.topic-count {
  flex-shrink: 0;
  font-family: var(--dna-font-mono);
  font-size: 0.78rem;
  color: var(--dna-muted);
}

.lesson-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.lesson-row {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.9rem 1.1rem;
  border-radius: var(--dna-radius-sm);
  background: var(--dna-glass);
  border: 1px solid var(--dna-line);
  text-decoration: none;
  color: var(--dna-ink);
  transition: background-color 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
}

.lesson-row:hover {
  background: var(--dna-glass-hover);
  border-color: rgba(34, 211, 238, 0.4);
  transform: translateX(3px);
}

.lesson-row-num {
  flex: 0 0 2rem;
  font-family: var(--dna-font-mono);
  font-size: 0.8rem;
  color: var(--dna-faint);
}

.lesson-row-body {
  flex: 1 1 auto;
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 0.1rem;
}

.lesson-row-title {
  font-weight: 600;
  font-size: 1rem;
  line-height: 1.35;
  color: var(--dna-ink);
}

.lesson-row-meta {
  font-size: 0.8rem;
  color: var(--dna-muted);
  overflow-wrap: anywhere;
}

.lesson-row-chevron {
  flex-shrink: 0;
  color: var(--dna-faint);
  transition: transform 0.2s ease, color 0.2s ease;
}

.lesson-row:hover .lesson-row-num,
.lesson-row:hover .lesson-row-chevron {
  color: var(--aurora-cyan);
}

.lesson-row:hover .lesson-row-chevron {
  transform: translateX(3px);
}

/* Search results */
.result-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  max-width: 62rem;
}

.result-row {
  display: block;
  padding: 1.1rem 1.25rem;
  border-radius: var(--dna-radius-sm);
  text-decoration: none;
  color: var(--dna-ink);
}

.result-title {
  display: block;
  font-size: 1.15rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  line-height: 1.35;
  overflow-wrap: anywhere;
  transition: color 0.2s ease;
}

.result-row:hover .result-title {
  color: var(--aurora-cyan);
}

.result-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.2rem 1.25rem;
  margin-top: 0.35rem;
  font-size: 0.85rem;
  color: var(--dna-muted);
}

.results-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.25rem 1rem;
  margin-bottom: 1.25rem;
}

.results-head h2 {
  margin: 0;
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: #ffffff;
}

.results-count {
  font-family: var(--dna-font-mono);
  font-size: 0.8rem;
  color: var(--aurora-cyan);
}

/* ---------------------------------------------------------
   Lesson page — reading progress
   --------------------------------------------------------- */
.reading-progress {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  z-index: 1100;
  pointer-events: none;
}

.reading-progress > span {
  display: block;
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, #7c5cff, #22d3ee);
  box-shadow: 0 0 12px rgba(34, 211, 238, 0.7);
  transition: width 0.1s linear;
}

/* ---------------------------------------------------------
   Lesson page — head
   --------------------------------------------------------- */
.lesson-head {
  padding: 1.25rem 0 2.25rem;
  margin-bottom: 2.5rem;
  border-bottom: 1px solid var(--dna-line);
}

.lesson-title {
  font-size: clamp(2rem, 1.2rem + 3vw, 3.4rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
  color: #ffffff;
  margin: 1.5rem 0 1.25rem;
  max-width: 26ch;
  overflow-wrap: anywhere;
}

.lesson-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 0;
}

.lesson-meta span {
  font-family: var(--dna-font-mono);
  font-size: 0.78rem;
  padding: 0.3rem 0.75rem;
  border-radius: 999px;
  color: var(--dna-body);
  background: var(--dna-glass);
  border: 1px solid var(--dna-line);
}

.lesson-head-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.625rem;
  margin-top: 1.25rem;
}

/* ---------------------------------------------------------
   Lesson page — layout grid
   --------------------------------------------------------- */
.lesson-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2rem;
  align-items: start;
  margin-bottom: 4rem;
}

@media (min-width: 992px) {
  .lesson-layout {
    grid-template-columns: 17rem minmax(0, 1fr);
    gap: 3rem;
  }
}

@media (min-width: 1400px) {
  .lesson-layout {
    grid-template-columns: 17rem minmax(0, 1fr) 14rem;
    gap: 3.5rem;
  }
}

/* Course outline (left) */
.lesson-outline {
  position: sticky;
  top: calc(var(--dna-header-h) + 1.5rem);
  min-width: 0;
}

.lesson-outline-inner {
  max-height: calc(100vh - var(--dna-header-h) - 3rem);
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: #3a4566 transparent;
  padding-right: 0.5rem;
}

.lesson-outline-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 0.75rem;
  margin-bottom: 1.25rem;
  padding-bottom: 0.9rem;
  border-bottom: 1px solid var(--dna-line);
}

.lesson-outline-head > div {
  flex: 1 1 auto;
  min-width: 0;
}

.lesson-outline-eyebrow {
  display: block;
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--dna-muted);
  margin-bottom: 0.15rem;
}

.lesson-outline-title {
  display: block;
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: -0.015em;
  line-height: 1.3;
  color: #ffffff;
  text-decoration: none;
  overflow-wrap: anywhere;
}

.lesson-outline-title:hover {
  color: var(--aurora-cyan);
}

.outline-close {
  flex-shrink: 0;
  width: 2.25rem;
  height: 2.25rem;
  border-radius: 999px;
  border: 1px solid var(--dna-line-strong);
  background: var(--dna-glass);
  color: var(--dna-ink);
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.outline-group + .outline-group {
  margin-top: 1.25rem;
}

.outline-group-title {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.5rem;
  margin-bottom: 0.3rem;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--dna-ink);
}

.outline-group-count {
  flex-shrink: 0;
  font-family: var(--dna-font-mono);
  font-size: 0.72rem;
  color: var(--dna-muted);
}

.outline-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.outline-item {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  padding: 0.4rem 0.6rem;
  border-radius: 0.5rem;
  color: var(--dna-body);
  font-size: 0.95rem;
  font-weight: 450;
  line-height: 1.4;
  text-decoration: none;
  transition: background-color 0.2s ease, color 0.2s ease;
}

.outline-item:hover {
  background: var(--dna-glass-hover);
  color: #ffffff;
}

.outline-item.is-current {
  color: #ffffff;
  font-weight: 600;
  background: rgba(34, 211, 238, 0.12);
  box-shadow: inset 2px 0 0 var(--aurora-cyan);
}

.outline-item.is-done {
  color: var(--dna-muted);
}

.outline-num {
  flex: 0 0 1.6rem;
  font-family: var(--dna-font-mono);
  font-size: 0.8rem;
  text-align: right;
  color: var(--dna-faint);
}

.outline-item.is-current .outline-num {
  color: var(--aurora-cyan);
}

.outline-label {
  min-width: 0;
  overflow-wrap: anywhere;
}

.outline-backdrop {
  display: none;
}

/* Mobile: outline becomes a slide-in drawer */
@media (max-width: 991.98px) {
  .lesson-outline {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    width: min(340px, 88vw);
    z-index: 1061;
    transform: translateX(-105%);
    visibility: hidden;
    transition: transform 0.25s ease, visibility 0s linear 0.25s;
  }

  .lesson-outline.is-open {
    transform: none;
    visibility: visible;
    transition: transform 0.25s ease;
  }

  .lesson-outline-inner {
    height: 100%;
    max-height: none;
    background-color: var(--dna-bg-raised);
    border-right: 1px solid var(--dna-line-strong);
    box-shadow: 0 0 60px rgba(0, 0, 0, 0.6);
    padding: 1.25rem;
  }

  .outline-backdrop {
    display: block;
    position: fixed;
    inset: 0;
    z-index: 1060;
    background-color: rgba(4, 7, 16, 0.7);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.25s ease, visibility 0s linear 0.25s;
  }

  .outline-backdrop.is-open {
    opacity: 1;
    visibility: visible;
    transition: opacity 0.25s ease;
  }

  body.outline-open {
    overflow: hidden;
  }
}

/* Article (centre) */
.lesson-article {
  min-width: 0;
  max-width: 56rem;
}

.lesson-cover {
  margin: 0 0 2.5rem;
  border-radius: var(--dna-radius);
  overflow: hidden;
  border: 1px solid var(--dna-line);
  background-color: var(--dna-glass);
}

.lesson-cover img {
  display: block;
  width: 100%;
  height: auto;
  max-height: 520px;
  object-fit: cover;
}

/* On this page (right) */
.lesson-toc {
  display: none;
}

.lesson-toc[hidden] {
  display: none !important;
}

@media (min-width: 1400px) {
  .lesson-toc {
    display: block;
    position: sticky;
    top: calc(var(--dna-header-h) + 1.5rem);
    min-width: 0;
  }
}

.lesson-toc-inner {
  max-height: calc(100vh - var(--dna-header-h) - 3rem);
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: #3a4566 transparent;
}

.lesson-toc-title {
  display: block;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--dna-ink);
  margin-bottom: 0.75rem;
}

.lesson-toc-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-left: 1px solid var(--dna-line);
}

.toc-link {
  display: block;
  padding: 0.3rem 0.875rem;
  margin-left: -1px;
  border-left: 2px solid transparent;
  font-size: 0.92rem;
  font-weight: 450;
  line-height: 1.4;
  color: var(--dna-muted);
  text-decoration: none;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.toc-h3 .toc-link {
  padding-left: 1.75rem;
  font-size: 0.86rem;
}

.toc-link:hover {
  color: #ffffff;
}

.toc-link.is-active {
  color: var(--aurora-cyan);
  border-left-color: var(--aurora-cyan);
  font-weight: 600;
}

/* ---------------------------------------------------------
   Lesson page — article typography
   Prose runs in a measured column; code, tables and figures
   use the full article width.
   --------------------------------------------------------- */
.lesson-content {
  font-family: var(--dna-font-prose);
  font-size: 1.25rem;
  line-height: 1.75;
  color: var(--dna-body);
  overflow-wrap: break-word;
}

/* ~66 characters per line at any font size */
.lesson-content > :is(p, ul, ol, blockquote, .alert-box, .takeaways, h1, h2, h3, h4, h5, h6) {
  max-width: 66ch;
}

.lesson-content > :first-child {
  margin-top: 0;
}

.lesson-content h1,
.lesson-content h2,
.lesson-content h3,
.lesson-content h4,
.lesson-content h5,
.lesson-content h6 {
  position: relative;
  margin-top: 3rem;
  margin-bottom: 1rem;
  font-family: var(--dna-font-ui);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.25;
  color: #ffffff;
  scroll-margin-top: calc(var(--dna-header-h) + 1.5rem);
}

.lesson-content h1 { font-size: 2.35rem; }
.lesson-content h2 { font-size: 1.95rem; }
.lesson-content h3 { font-size: 1.5rem; font-weight: 650; }
.lesson-content h4 { font-size: 1.25rem; font-weight: 650; letter-spacing: -0.01em; }

.lesson-content .heading-anchor {
  margin-left: 0.5rem;
  font-weight: 500;
  color: var(--dna-faint);
  text-decoration: none;
  opacity: 0;
  transition: opacity 0.15s ease, color 0.15s ease;
}

.lesson-content h2:hover .heading-anchor,
.lesson-content h3:hover .heading-anchor,
.lesson-content .heading-anchor:focus-visible {
  opacity: 1;
}

.lesson-content .heading-anchor:hover {
  color: var(--aurora-cyan);
}

.lesson-content p {
  margin-bottom: 1.35rem;
}

.lesson-content strong {
  color: #ffffff;
  font-weight: 600;
}

.lesson-content img {
  max-width: 100%;
  height: auto;
  margin: 1.75rem 0;
  border-radius: var(--dna-radius-sm);
  border: 1px solid var(--dna-line);
}

.lesson-content hr {
  margin: 3rem 0;
  border: 0;
  border-top: 1px solid var(--dna-line);
  opacity: 1;
}

/* Lists */
.lesson-content ul,
.lesson-content ol {
  margin: 0 0 1.35rem 0;
  padding-left: 1.6rem;
}

.lesson-content ul li,
.lesson-content ol li {
  margin-bottom: 0.5rem;
  padding-left: 0.3rem;
}

.lesson-content ul li::marker,
.lesson-content ol li::marker {
  color: var(--aurora-cyan);
  font-weight: 600;
}

/* Quill emits ordered lists for bullets, flagged via data-list */
.lesson-content ol li[data-list="bullet"] {
  list-style-type: disc;
}

/* Blockquote */
.lesson-content blockquote {
  border-left: 3px solid var(--aurora-violet);
  margin: 2rem 0;
  padding: 0.9rem 1.4rem;
  border-radius: 0 var(--dna-radius-sm) var(--dna-radius-sm) 0;
  background: linear-gradient(90deg, rgba(124, 92, 255, 0.14), rgba(124, 92, 255, 0.02));
  color: #e2e8f0;
}

.lesson-content blockquote p:last-child {
  margin-bottom: 0;
}

/* Opening paragraph reads as a lede */
.lesson-content > p:first-child {
  font-size: 1.12em;
  line-height: 1.7;
  color: #e6ebf7;
}

/* Callouts: the editor's alert-box block (info, warning, success, danger) */
.lesson-content .alert-box {
  --c: 34, 211, 238;
  position: relative;
  margin: 1.75rem 0;
  padding: 1rem 1.25rem 1rem 3.4rem;
  border-radius: var(--dna-radius-sm);
  border: 1px solid rgba(var(--c), 0.4);
  border-left-width: 4px;
  background: linear-gradient(90deg, rgba(var(--c), 0.14), rgba(var(--c), 0.05));
  color: #e6ebf7;
  font-size: 0.95em;
  line-height: 1.65;
}

.lesson-content .alert-box::before {
  content: "\f431";
  position: absolute;
  left: 1.15rem;
  top: 1.05rem;
  font-family: "bootstrap-icons";
  font-size: 1.2rem;
  line-height: 1;
  color: rgb(var(--c));
}

.lesson-content .alert-box.alert-warning { --c: 255, 176, 66; }
.lesson-content .alert-box.alert-warning::before { content: "\f33b"; }
.lesson-content .alert-box.alert-success { --c: 74, 222, 128; }
.lesson-content .alert-box.alert-success::before { content: "\f26b"; }
.lesson-content .alert-box.alert-danger { --c: 251, 113, 133; }
.lesson-content .alert-box.alert-danger::before { content: "\f336"; }

.lesson-content .alert-box strong {
  color: rgb(var(--c));
}

/* Numbered steps (lesson.js turns "Step 3 — Title" into a badge + title) */
.lesson-content h3.step-heading {
  padding-left: 3.1rem;
  min-height: 2.25rem;
}

.lesson-content .step-num {
  position: absolute;
  left: 0;
  top: -0.05em;
  display: grid;
  place-items: center;
  width: 2.25rem;
  height: 2.25rem;
  border-radius: 50%;
  background: var(--dna-gradient);
  color: #0b1020;
  font-family: var(--dna-font-mono);
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: 0;
  box-shadow: 0 0 16px rgba(34, 211, 238, 0.35);
}

/* Closing summary card */
.lesson-content .takeaways {
  margin: 3.5rem 0 0;
  padding: 1.75rem 2rem 1.25rem;
  border-radius: var(--dna-radius);
  border: 1px solid rgba(154, 128, 255, 0.4);
  background:
    radial-gradient(120% 100% at 100% 0%, rgba(124, 92, 255, 0.2), transparent 60%),
    var(--dna-glass);
}

.lesson-content .takeaways > h2 {
  margin-top: 0;
  font-size: 1.5rem;
}

.lesson-content .takeaways > :last-child {
  margin-bottom: 0.5rem;
}

.lesson-content .takeaways ul li::marker {
  color: var(--aurora-lime);
}

@media (max-width: 575.98px) {
  .lesson-content .takeaways {
    padding: 1.25rem 1.25rem 0.75rem;
  }
}

/* Inline code */
.lesson-content :not(pre) > code {
  background-color: rgba(154, 128, 255, 0.24);
  border: 1px solid rgba(154, 128, 255, 0.5);
  color: #f4f1ff;
  padding: 0.04em 0.3em;
  margin: 0;
  letter-spacing: normal;
  border-radius: 0.4rem;
  font-family: var(--dna-font-mono);
  font-size: 0.9em;
  font-weight: 500;
  -webkit-box-decoration-break: clone;
  box-decoration-break: clone;
}

/* Code blocks (Prism) */
.lesson-content pre[class*="language-"] {
  background-color: var(--dna-code-bg);
  color: #e2e8f0;
  padding: 1.35rem 1.5rem;
  border-radius: var(--dna-radius-sm);
  overflow-x: auto;
  margin: 0;
  border: 1px solid var(--dna-code-border);
  font-family: var(--dna-font-mono);
  font-size: 0.95rem;
  line-height: 1.7;
  position: relative;
  text-shadow: none;
  scrollbar-width: thin;
  scrollbar-color: #3a4566 transparent;
}

.lesson-content pre[class*="language-"]::-webkit-scrollbar {
  height: 8px;
}

.lesson-content pre[class*="language-"]::-webkit-scrollbar-thumb {
  background: #3a4566;
  border-radius: 4px;
}

.lesson-content pre[class*="language-"]::-webkit-scrollbar-track {
  background: transparent;
}

.lesson-content code[class*="language-"] {
  font-family: var(--dna-font-mono);
  color: #e2e8f0;
  text-shadow: none;
}

.lesson-content pre.line-numbers {
  position: relative;
  padding-left: 3.8em;
  counter-reset: linenumber;
}

.lesson-content pre.line-numbers > code {
  position: relative;
  white-space: inherit;
}

.lesson-content .line-numbers .line-numbers-rows {
  position: absolute;
  pointer-events: none;
  top: 0;
  font-size: 100%;
  left: -3.8em;
  width: 3em;
  letter-spacing: -1px;
  border-right: 1px solid var(--dna-code-border);
  user-select: none;
}

.lesson-content .line-numbers-rows > span {
  display: block;
  counter-increment: linenumber;
}

.lesson-content .line-numbers-rows > span:before {
  content: counter(linenumber);
  color: #5f6b87;
  display: block;
  padding-right: 0.8em;
  text-align: right;
}

/* Token colours — the aurora palette (loaded after Prism's theme) */
.lesson-content .token.comment,
.lesson-content .token.prolog,
.lesson-content .token.doctype,
.lesson-content .token.cdata { color: #7d89a8; font-style: italic; }
.lesson-content .token.punctuation { color: #aab4cc; }
.lesson-content .token.keyword,
.lesson-content .token.atrule,
.lesson-content .token.selector,
.lesson-content .token.important { color: #f472b6; }
.lesson-content .token.string,
.lesson-content .token.char,
.lesson-content .token.attr-value,
.lesson-content .token.inserted { color: #bef264; }
.lesson-content .token.number,
.lesson-content .token.boolean,
.lesson-content .token.constant,
.lesson-content .token.symbol { color: #ffb066; }
.lesson-content .token.function,
.lesson-content .token.method { color: #67e8f9; }
.lesson-content .token.class-name,
.lesson-content .token.builtin,
.lesson-content .token.tag { color: #b3a3ff; }
.lesson-content .token.property,
.lesson-content .token.attr-name,
.lesson-content .token.variable,
.lesson-content .token.parameter { color: #e2e8f0; }
.lesson-content .token.operator,
.lesson-content .token.entity,
.lesson-content .token.url { color: #aab4cc; background: none; }
.lesson-content .token.deleted { color: #fb7185; }

.lesson-content div.code-toolbar {
  position: relative;
  margin: 2rem 0;
}

.lesson-content div.code-toolbar > .toolbar {
  position: absolute;
  top: 0.6rem;
  right: 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
  opacity: 1;
}

.lesson-content div.code-toolbar > .toolbar > .toolbar-item {
  display: inline-flex;
}

.lesson-content div.code-toolbar > .toolbar > .toolbar-item > span {
  color: #94a0ba;
  font-family: var(--dna-font-mono);
  font-size: 0.8rem;
  font-weight: 500;
  background: none;
  box-shadow: none;
  padding: 0.3rem 0.5rem;
}

.lesson-content div.code-toolbar > .toolbar > .toolbar-item > button {
  background-color: rgba(255, 255, 255, 0.07);
  color: #d5dcec;
  border: 1px solid rgba(255, 255, 255, 0.16);
  padding: 0.3rem 0.75rem;
  border-radius: 999px;
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  box-shadow: none;
  transition: background-color 0.15s ease, color 0.15s ease, border-color 0.15s ease;
  font-family: var(--dna-font-ui);
}

.lesson-content div.code-toolbar > .toolbar > .toolbar-item > button:hover,
.lesson-content div.code-toolbar > .toolbar > .toolbar-item > button:focus {
  background-color: var(--aurora-cyan);
  border-color: var(--aurora-cyan);
  color: #0b1020;
  outline: none;
}

/* Tables */
.lesson-content .table-scroll {
  margin: 2rem 0;
  overflow-x: auto;
  border-radius: var(--dna-radius-sm);
  border: 1px solid var(--dna-line);
  background: var(--dna-glass);
}

.lesson-content table {
  width: 100%;
  margin: 0;
  border-collapse: collapse;
  font-family: var(--dna-font-ui);
  font-size: 1rem;
  line-height: 1.55;
}

.lesson-content table th {
  padding: 0.85rem 1.1rem;
  font-weight: 650;
  color: #ffffff;
  text-align: left;
  background: rgba(255, 255, 255, 0.05);
  border: 0;
  border-bottom: 1px solid var(--dna-line-strong);
  white-space: nowrap;
}

.lesson-content table td {
  padding: 0.85rem 1.1rem;
  color: var(--dna-body);
  border: 0;
  border-bottom: 1px solid var(--dna-line);
  vertical-align: top;
}

.lesson-content table tbody tr:last-child td {
  border-bottom: 0;
}

/* Links inside content */
.lesson-content a {
  color: var(--dna-link);
  text-decoration: underline;
  text-decoration-color: rgba(103, 232, 249, 0.4);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
  font-weight: 500;
}

.lesson-content a:hover {
  color: #ffffff;
  text-decoration-color: currentColor;
}

/* ---------------------------------------------------------
   Lesson page — footer (share + pager)
   --------------------------------------------------------- */
.lesson-footer {
  margin-top: 4rem;
}

.lesson-share {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem 1rem;
  padding: 1.1rem 0;
  border-top: 1px solid var(--dna-line);
  border-bottom: 1px solid var(--dna-line);
}

.lesson-share-label {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--dna-ink);
}

.lesson-share-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.share-btn {
  width: 2.5rem;
  height: 2.5rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  border: 1px solid var(--dna-line);
  background-color: var(--dna-glass);
  color: var(--dna-body);
  font-size: 1rem;
  text-decoration: none;
  cursor: pointer;
  transition: background-color 0.2s ease, border-color 0.2s ease, color 0.2s ease;
}

.share-btn:hover {
  background-color: rgba(34, 211, 238, 0.15);
  border-color: rgba(34, 211, 238, 0.5);
  color: var(--aurora-cyan);
}

.share-btn.is-copied {
  background-color: rgba(74, 222, 128, 0.2);
  border-color: var(--dna-success);
  color: var(--dna-success);
}

.lesson-pager {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
  margin-top: 2rem;
}

@media (min-width: 576px) {
  .lesson-pager {
    grid-template-columns: 1fr 1fr;
  }
}

.pager-card {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  min-width: 0;
  padding: 1.25rem 1.4rem;
  border-radius: var(--dna-radius);
  background: var(--dna-glass);
  border: 1px solid var(--dna-line);
  text-decoration: none;
  transition: background-color 0.25s ease, border-color 0.25s ease, transform 0.25s ease;
}

.pager-card:hover {
  background: var(--dna-glass-hover);
  border-color: rgba(34, 211, 238, 0.45);
  transform: translateY(-2px);
}

.pager-next {
  align-items: flex-end;
  text-align: right;
}

.pager-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--dna-muted);
}

.pager-title {
  font-size: 1.05rem;
  font-weight: 650;
  letter-spacing: -0.01em;
  line-height: 1.35;
  color: #ffffff;
  overflow-wrap: anywhere;
  transition: color 0.2s ease;
}

.pager-card:hover .pager-title {
  color: var(--aurora-cyan);
}

.pager-muted .pager-title {
  font-weight: 600;
  color: var(--dna-body);
}

/* ---------------------------------------------------------
   Admin
   --------------------------------------------------------- */
.admin-page-header {
  margin-bottom: 2rem;
}

.admin-page-header .admin-page-title {
  color: #ffffff;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 0.25rem;
}

.admin-page-header .breadcrumb {
  margin-bottom: 0;
}

.admin-stat-card .stat-icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--dna-radius-sm);
  flex-shrink: 0;
}

.admin-stat-card .stat-value {
  color: #ffffff;
  font-size: 2.25rem;
  font-weight: 700;
  line-height: 1.1;
}

.admin-stat-card .stat-label {
  color: var(--dna-muted);
  font-weight: 600;
  font-size: 0.95rem;
}

.timeline {
  position: relative;
}

.timeline-item {
  display: flex;
  position: relative;
}

.timeline-line {
  position: absolute;
  left: 20px;
  top: 40px;
  bottom: 0;
  width: 2px;
  background-color: var(--dna-line);
}

.timeline-item:last-child .timeline-line {
  display: none;
}

.timeline-icon {
  position: relative;
  z-index: 1;
  flex-shrink: 0;
}

.timeline-content {
  flex: 1;
  margin-left: 20px;
}

.stat-item {
  padding: 0.5rem;
  border-radius: var(--dna-radius-sm);
}

.stat-item:hover {
  background-color: var(--dna-glass-hover);
}

.stat-item-total {
  padding: 1rem;
  border-radius: var(--dna-radius-sm);
  background-color: var(--dna-glass);
  border: 1px solid var(--dna-line);
}

.sortable-item {
  transition: background-color 0.2s ease, border-color 0.2s ease;
}

.sortable-item:hover {
  background-color: var(--dna-glass-hover);
}

.sortable-ghost {
  opacity: 0.4;
  background-color: var(--dna-glass-hover);
}

.sortable-chosen {
  background-color: rgba(124, 92, 255, 0.18);
}

.sortable-drag {
  opacity: 1;
}

.lesson-title-image {
  display: flex;
  justify-content: center;
  align-items: center;
  margin: 1.5rem 0;
}

.lesson-title-image img {
  max-width: 100%;
  max-height: 400px;
  width: auto;
  height: auto;
  object-fit: contain;
  border-radius: var(--dna-radius-sm);
  border: 1px solid var(--dna-line);
}

.lesson-list-item {
  transition: background-color 0.2s ease;
}

.lesson-list-item:hover {
  background-color: var(--dna-glass-hover);
}

.lesson-list-item:last-child {
  border-bottom: none !important;
}

/* ---------------------------------------------------------
   Footer
   --------------------------------------------------------- */
#kt_footer {
  background-color: rgba(11, 16, 32, 0.9);
  border-top: 1px solid var(--dna-line);
  margin-bottom: 0 !important;
  flex-shrink: 0;
}

#kt_footer .footer-brand {
  color: #ffffff;
  font-weight: 700;
  letter-spacing: -0.02em;
}

#kt_footer .footer-tagline {
  font-family: var(--dna-font-prose);
  font-weight: 400;
  font-size: 0.95rem !important;
  line-height: 1.55;
  color: var(--dna-muted);
  max-width: 22rem;
}

#kt_footer h5 {
  font-size: 0.9rem !important;
  font-weight: 650;
  color: #ffffff !important;
}

#kt_footer .menu-link {
  color: var(--dna-muted) !important;
  font-size: 0.9rem !important;
  font-weight: 450;
  background: none !important;
}

#kt_footer .menu-link:hover {
  color: #ffffff !important;
}

#kt_footer .footer-bottom {
  border-top: 1px solid var(--dna-line);
}

#kt_footer .footer-bottom a.text-muted {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  border-radius: 50%;
  background: var(--dna-glass);
  border: 1px solid var(--dna-line);
  transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

#kt_footer .footer-bottom a.text-muted:hover {
  background: rgba(124, 92, 255, 0.2);
  border-color: rgba(124, 92, 255, 0.5);
  color: #cfc6ff !important;
}

/* ---------------------------------------------------------
   Layout guards (Metronic flex fixes)
   --------------------------------------------------------- */
.card-body {
  min-height: 0;
}

#kt_content_container {
  min-height: 0;
}

.content.flex-row-fluid,
.flex-lg-row-fluid {
  min-width: 0;
}

#kt_scrolltop {
  margin: 0;
  padding: 0;
}

#kt_wrapper,
.flex-root,
.page {
  margin-bottom: 0 !important;
  padding-bottom: 0 !important;
}

/* Discovery and navigation */
.skip-link {
  position: fixed;
  top: -6rem;
  left: 1rem;
  z-index: 1100;
  padding: 0.75rem 1rem;
  background: var(--aurora-cyan);
  color: #0b1020;
  font-weight: 600;
  border-radius: 999px;
}

.skip-link:focus {
  top: 0.75rem;
  color: #0b1020;
}

.compact-disclosure {
  border: 1px solid var(--dna-line);
  border-radius: var(--dna-radius-sm);
  background: var(--dna-glass);
  padding: 0.9rem 1.1rem;
  margin-bottom: 1.5rem;
}

.compact-disclosure > summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--dna-ink);
}

.compact-disclosure[open] > summary {
  margin-bottom: 0.75rem;
}

.compact-disclosure .topic-link,
.mobile-toc .toc-link {
  padding-block: 0.6rem;
}

.mobile-toc[hidden] {
  display: none;
}

@media (min-width: 1400px) {
  .mobile-toc {
    display: none;
  }
}

@media (max-width: 575.98px) {
  .lesson-content {
    font-size: 1.125rem;
  }

  .lesson-content h2 { font-size: 1.65rem; }
  .lesson-content h3 { font-size: 1.3rem; }

  #kt_header .brand-title {
    font-size: 1.05rem;
  }

  #kt_header .container-xxl {
    padding-inline: 0.75rem;
  }

  #kt_header_menu_toggle {
    margin-right: 0.35rem !important;
  }

  #kt_header img {
    height: 28px !important;
  }

  .big-search {
    flex-wrap: wrap;
    border-radius: 1.5rem;
  }

  .big-search .form-control {
    flex: 1 1 calc(100% - 3rem);
  }

  .big-search .btn {
    flex: 1 1 100%;
    margin-top: 0.4rem;
  }

  .lesson-cover img {
    max-height: 260px;
  }

  /* Keep the language label and Copy button off the first line of code */
  .lesson-content div.code-toolbar > pre[class*="language-"] {
    padding-top: 2.75rem;
  }

  .lesson-content div.code-toolbar > .toolbar {
    top: 0.45rem;
  }

  .topic-head {
    flex-wrap: wrap;
    gap: 0.35rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .glass,
  .lesson-row,
  .lesson-row-chevron,
  .pager-card,
  .share-btn,
  .latest-arrow,
  .lesson-outline,
  .outline-backdrop {
    transition: none;
  }

  .glass:hover,
  .lesson-row:hover,
  .pager-card:hover {
    transform: none;
  }
}

.lesson-list-item > .flex-grow-1 {
  min-width: 0;
}

.lesson-list-item .badge {
  white-space: normal;
  text-align: left;
  overflow-wrap: anywhere;
  max-width: 100%;
  line-height: 1.5;
}

@media (max-width: 575.98px) {
  .lesson-list-item {
    flex-wrap: wrap;
    gap: 1rem;
  }

  .lesson-list-item > .flex-grow-1 {
    flex-basis: 100%;
  }

  .lesson-list-item > .btn {
    margin-left: 0 !important;
  }
}