:root {
  --bg: #f6f1e8;
  --bg-elev: #efe7da;
  --bg-card: #fffaf2;
  --lab: #f1e9dd;
  --line: #dccfbc;
  --line-strong: #c6b499;
  --cyan: #0891b2;
  --cyan-dim: rgba(8, 145, 178, 0.1);
  --cyan-glow: rgba(8, 145, 178, 0.22);
  --text: #2f2418;
  --heading: #23180e;
  --muted: #6b5a47;
  --silver: #4f3f2d;
  --warn: #b45309;
  --unk: #e11d48;
  --ok: #059669;
  --paper-top: #faf6ef;
  --paper-bottom: #f3ecdf;
  --dot: rgba(80, 58, 34, 0.09);
  --shadow-1: 0 1px 2px rgba(35, 24, 14, 0.12);
  --shadow-2: 0 3px 8px rgba(35, 24, 14, 0.14);
  --mono: "IBM Plex Mono", "ui-monospace", "SFMono-Regular", Menlo, Consolas, monospace;
  --sans: "Geist", "IBM Plex Sans", ui-sans-serif, system-ui, sans-serif;
  --radius: 8px;
  --nav-width: 248px;
  --max: 68ch;
  --lab-max: 920px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 8.2rem;
}

#syllabus,
section[id] {
  scroll-margin-top: 8.2rem;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--sans);
  background-color: var(--bg);
  background-image:
    radial-gradient(circle, var(--dot) 0.75px, transparent 0.75px),
    linear-gradient(180deg, var(--paper-top) 0%, var(--paper-bottom) 100%);
  background-size: 20px 20px, auto;
  background-position: 0 0, 0 0;
  color: var(--text);
  line-height: 1.7;
  font-size: 1.05rem;
  font-feature-settings: "ss01", "cv11";
}

img {
  max-width: 100%;
}

a {
  color: var(--cyan);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
  text-underline-offset: 0.18em;
}

code {
  font-family: var(--mono);
  font-size: 0.86em;
  color: var(--cyan);
}

.skip {
  position: absolute;
  left: -999px;
  top: 0;
}

.skip:focus {
  left: 1rem;
  top: 1rem;
  z-index: 20;
  background: var(--cyan);
  color: #09090b;
  padding: 0.4rem 0.7rem;
  border-radius: 4px;
}

.github-top-right {
  position: fixed;
  top: 0.9rem;
  right: 1rem;
  z-index: 25;
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.38rem 0.62rem;
  border: 1px solid #c9b99f;
  background: #fffaf2;
  color: var(--heading);
  border-radius: 999px;
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  text-decoration: none;
  box-shadow: var(--shadow-1);
  transition: transform 120ms ease, box-shadow 120ms ease, border-color 120ms ease, color 120ms ease;
}

.github-top-right svg {
  width: 0.9rem;
  height: 0.9rem;
  fill: currentColor;
}

.github-top-right:hover {
  color: var(--cyan);
  border-color: var(--cyan);
  box-shadow: var(--shadow-2);
  transform: translateY(-1px);
  text-decoration: none;
}

.github-top-right:active {
  transform: translateY(0);
  box-shadow: var(--shadow-1);
}

.app {
  display: grid;
  grid-template-columns: 1fr;
  min-height: 100vh;
}

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 15;
  height: auto;
  padding: 0.72rem 1rem 0.56rem;
  border-bottom: 1px solid var(--line);
  background: var(--bg);
  overflow: hidden;
}

.nav-kicker {
  margin: 0;
  font-family: var(--mono);
  font-size: 0.65rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
}

.nav-title {
  margin: 0.18rem 0 0.5rem;
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.3;
  color: var(--heading);
}

.nav ol {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 0.35rem;
  overflow-x: auto;
  scrollbar-width: thin;
}

.nav li {
  margin: 0;
  flex: 0 0 auto;
}

.nav a {
  display: flex;
  gap: 0.45rem;
  align-items: center;
  white-space: nowrap;
  padding: 0.36rem 0.66rem;
  margin-left: 0;
  color: var(--heading);
  font-size: 0.78rem;
  text-decoration: none;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  background: var(--bg-card);
  box-shadow: var(--shadow-1);
  transition: background-color 120ms ease, color 120ms ease, border-color 120ms ease, box-shadow 120ms ease, transform 120ms ease;
}

.nav a:hover {
  color: var(--heading);
  background: #f7efe2;
  border-color: #d6c5ab;
  box-shadow: var(--shadow-1);
  transform: translateY(-1px);
  text-decoration: none;
}

.nav a[aria-current="true"] {
  color: #ffffff;
  border-color: #0b7f99;
  background: linear-gradient(180deg, #1498b6 0%, #0b87a2 100%);
  box-shadow: var(--shadow-2);
}

.nav a:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 1px;
}

.nav-num {
  font-family: var(--mono);
  font-size: 0.68rem;
  color: var(--muted);
}

.nav a[aria-current="true"] .nav-num {
  color: #e8fbff;
}

.nav-note {
  display: none;
}

.nav-note code {
  font-size: 0.7rem;
}

main {
  padding: 8.8rem 3rem 7rem;
}

.hero {
  max-width: var(--lab-max);
  margin-bottom: 3rem;
}

.hero-kicker {
  margin: 0 0 0.85rem;
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--cyan);
}

.hero h1 {
  margin: 0;
  font-weight: 600;
  font-size: clamp(2.4rem, 5vw, 3.6rem);
  letter-spacing: -0.045em;
  color: var(--heading);
  line-height: 1.05;
}

.hero-sub {
  margin: 0.4rem 0 0;
  font-size: 1.15rem;
  color: var(--muted);
  letter-spacing: -0.02em;
}

.rule {
  height: 1px;
  background: var(--line);
  margin: 1.6rem 0 1.4rem;
  max-width: 12rem;
}

.syllabus {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.syllabus li {
  display: grid;
  grid-template-columns: 4.5rem minmax(0, 1fr) auto;
  gap: 1rem;
  align-items: center;
  padding: 0.7rem 0;
  border-bottom: 1px solid var(--line);
  color: var(--silver);
  font-size: 0.98rem;
}

.syllabus .kind {
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
}

.syllabus li:hover {
  background: rgba(8, 145, 178, 0.05);
}

.syllabus a {
  color: var(--heading);
  display: inline-flex;
  align-items: baseline;
  gap: 0.45rem;
  min-width: 0;
  font-weight: 500;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 120ms ease, border-color 120ms ease;
}

.syllabus a .go {
  font-family: var(--mono);
  font-size: 0.8em;
  color: var(--cyan);
  opacity: 0;
  transform: translateX(-0.25rem);
  transition: opacity 140ms ease, transform 140ms ease;
}

.syllabus a:hover,
.syllabus a:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
  text-decoration: none;
}

.syllabus a:hover .go,
.syllabus a:focus-visible .go {
  opacity: 1;
  transform: translateX(0);
}

@media (prefers-reduced-motion: reduce) {
  .syllabus a .go {
    transition: none;
    transform: none;
  }
}

section {
  max-width: var(--max);
  margin: 4rem 0;
  padding-top: 0.2rem;
}

section.wide {
  max-width: var(--lab-max);
}

section h2 {
  margin: 0 0 1rem;
  font-size: clamp(1.55rem, 2.4vw, 1.95rem);
  font-weight: 600;
  letter-spacing: -0.03em;
  color: var(--heading);
  line-height: 1.2;
}

section h3 {
  margin: 2rem 0 0.55rem;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--heading);
}

p {
  margin: 0 0 1.05rem;
  color: var(--text);
}

.lede {
  font-size: 1.12rem;
  color: var(--muted);
  max-width: 58ch;
}

/* Hero intro: readable body copy, not mono footnotes. */
.hero-intro {
  margin-top: 2.1rem;
  max-width: 64ch;
}

.hero-intro .lede {
  margin-bottom: 1rem;
  font-size: 1.24rem;
  line-height: 1.62;
  letter-spacing: -0.011em;
  color: var(--heading);
}

.hero-intro .lede strong {
  font-weight: 600;
}

.hero-intro p {
  font-size: 1.04rem;
  line-height: 1.78;
  color: var(--silver);
  margin-bottom: 0.95rem;
}

.hero-intro p:last-child {
  margin-bottom: 0;
}

.hero-intro strong {
  color: var(--heading);
  font-weight: 600;
}

.hero-intro code {
  font-size: 0.84em;
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: 3px;
  padding: 0.06em 0.32em;
}

.callout {
  background: transparent;
  border: 1px solid var(--line);
  border-left: 2px solid var(--cyan);
  border-radius: 0;
  padding: 0.85rem 1.05rem;
  margin: 1.2rem 0 1.5rem;
  color: var(--muted);
  font-size: 0.95rem;
}

.callout strong {
  color: var(--heading);
}

.pipeline {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(108px, 1fr));
  gap: 1px;
  margin: 1.4rem 0 1.6rem;
  background: var(--line);
  border: 1px solid var(--line);
}

.stage {
  background: var(--bg);
  padding: 0.75rem 0.7rem;
  text-align: left;
  font-size: 0.75rem;
  color: var(--muted);
}

.stage strong {
  display: block;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--cyan);
  margin-bottom: 0.28rem;
  font-weight: 500;
}

.taxonomy {
  display: grid;
  gap: 0;
  margin: 1.3rem 0 1.6rem;
  border-top: 1px solid var(--line);
}

.tax-card {
  display: grid;
  grid-template-columns: 7.5rem 1fr;
  gap: 1rem;
  padding: 1rem 0;
  border-bottom: 1px solid var(--line);
}

.tax-card .level {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--cyan);
  padding-top: 0.2rem;
}

.tax-card p {
  margin: 0;
  font-size: 0.95rem;
  color: var(--muted);
}

.lab {
  --lab-radius: 6px;
  background-color: var(--lab);
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 24px 24px;
  background-position: -1px -1px;
  border: 1px solid var(--line-strong);
  border-radius: var(--lab-radius);
  padding: 1.05rem 1.1rem 1.2rem;
  margin: 1.4rem 0 1.8rem;
}

.lab-head {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: center;
  margin-bottom: 0.9rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--line-strong);
}

.lab-head h3 {
  margin: 0;
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-weight: 500;
  color: var(--heading);
}

.metrics {
  display: flex;
  flex-wrap: wrap;
  gap: 0.7rem;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.04em;
  color: var(--muted);
}

.metrics strong {
  color: var(--cyan);
  font-weight: 500;
  margin-left: 0.25rem;
}

.lab-tag {
  font-family: var(--mono);
  font-size: 0.65rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--cyan);
  border: 1px solid var(--line-strong);
  border-radius: 2px;
  padding: 0.15rem 0.45rem;
  white-space: nowrap;
}

label {
  display: block;
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0.75rem 0 0.35rem;
}

textarea,
input[type="text"],
select {
  width: 100%;
  background: var(--bg-card);
  color: var(--heading);
  border: 1px solid var(--line-strong);
  border-radius: 4px;
  padding: 0.65rem 0.75rem;
  font-family: var(--mono);
  font-size: 0.88rem;
  resize: vertical;
}

textarea:focus,
input[type="text"]:focus,
select:focus {
  outline: 1px solid var(--cyan);
  border-color: var(--cyan);
}

.row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin: 0.55rem 0 0.8rem;
}

.preset,
button {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.04em;
  background: transparent;
  color: var(--muted);
  border: 1px solid var(--line-strong);
  border-radius: 4px;
  padding: 0.28rem 0.6rem;
  cursor: pointer;
}

.preset:hover,
button:hover,
.preset[aria-pressed="true"],
button[aria-pressed="true"],
button[aria-selected="true"] {
  border-color: var(--cyan);
  color: var(--cyan);
  background: var(--cyan-dim);
}

.tabs {
  display: flex;
  gap: 0;
  border: 1px solid var(--line-strong);
  border-radius: 4px;
  overflow: hidden;
  margin: 0.2rem 0 0.6rem;
  width: fit-content;
  max-width: 100%;
}

.tabs button {
  border: 0;
  border-right: 1px solid var(--line-strong);
  border-radius: 0;
  padding: 0.45rem 0.9rem;
  background: var(--bg-card);
  color: var(--muted);
}

.tabs button:last-child {
  border-right: 0;
}

.tabs button[aria-selected="true"] {
  background: var(--cyan);
  color: #ffffff;
  font-weight: 600;
}

.sp-modes {
  display: flex;
  gap: 0.4rem;
  margin: 0 0 0.5rem;
}

.sp-modes.hidden {
  display: none;
}

.algo-rule {
  margin: 0.55rem 0 0.7rem;
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--muted);
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.6rem;
  margin-top: 0.85rem;
}

.pane {
  background: var(--bg-card);
  border: 1px solid var(--line-strong);
  border-radius: 4px;
  padding: 0.7rem 0.75rem 0.8rem;
  min-height: 8.2rem;
}

.pane-fixed {
  min-height: 7.5rem;
}

.pane-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 0.5rem;
  gap: 0.5rem;
}

.pane h4 {
  margin: 0;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
  font-weight: 500;
}

.count {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--cyan);
}

.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.28rem;
}

.chip {
  font-family: var(--mono);
  font-size: 0.74rem;
  line-height: 1.2;
  padding: 0.18rem 0.38rem;
  border-radius: 4px;
  background: var(--bg-elev);
  color: var(--text);
  border: 1px solid var(--line-strong);
  max-width: 100%;
  overflow-wrap: anywhere;
}

.chip.unk {
  background: #fbe4e8;
  border-color: var(--unk);
  color: #9f1239;
  font-weight: 500;
}

.chip.space {
  opacity: 0.85;
}

.stats {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 0.75rem;
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--muted);
}

.stats span strong {
  color: var(--heading);
  font-weight: 500;
}

.bytes-table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--mono);
  font-size: 0.78rem;
  margin-top: 0.55rem;
}

.bytes-table th,
.bytes-table td {
  text-align: left;
  padding: 0.38rem 0.4rem;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
}

.bytes-table th {
  color: var(--muted);
  font-weight: 500;
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.inspect-table-wrap {
  overflow-x: auto;
  border: 1px solid var(--line-strong);
  border-radius: 4px;
  background: var(--bg-card);
}

.preset[data-inspect-preset].is-active,
.preset[data-inspect-preset].is-active:hover,
.preset[data-inspect-preset][aria-pressed="true"] {
  border-color: var(--cyan);
  background: var(--cyan);
  color: #ffffff;
  font-weight: 600;
}

.inspect-table {
  margin-top: 0;
  min-width: 660px;
}

.inspect-table th {
  padding: 0.65rem 0.55rem;
  background: var(--cyan);
  color: #ffffff;
  border-bottom-color: var(--cyan);
}

.inspect-table td {
  padding: 0.55rem;
}

.inspect-table tbody tr:nth-child(even) {
  background: var(--cyan-dim);
}

.inspect-table tbody tr:hover {
  background: rgba(8, 145, 178, 0.16);
}

.inspect-table th:nth-child(3),
.inspect-table th:nth-child(5),
.inspect-table td:nth-child(3),
.inspect-table td:nth-child(5) {
  text-align: center;
}

.inspect-table td:nth-child(3),
.inspect-table td:nth-child(5) {
  color: var(--cyan);
  font-weight: 600;
}

.merge-log {
  font-family: var(--mono);
  font-size: 0.75rem;
  background: var(--bg-card);
  border: 1px solid var(--line-strong);
  border-radius: 4px;
  padding: 0.7rem 0.75rem;
  max-height: 14rem;
  min-height: 9rem;
  overflow: auto;
  white-space: pre-wrap;
  color: var(--silver);
  margin-top: 0.65rem;
}

.slider-row {
  display: grid;
  grid-template-columns: minmax(10rem, auto) 1fr;
  gap: 0.9rem;
  align-items: center;
  margin: 0.55rem 0;
}

.slider-row label {
  margin: 0;
}

input[type="range"] {
  width: 100%;
  accent-color: var(--cyan);
}

.bar-wrap {
  margin-top: 0.85rem;
}

.bar {
  display: flex;
  height: 0.55rem;
  border-radius: 1px;
  overflow: hidden;
  border: 0;
  background: var(--line-strong);
}

.bar > i {
  display: block;
  height: 100%;
}

.dl {
  margin: 0.4rem 0 1rem;
}

.dl div {
  display: grid;
  grid-template-columns: 8.5rem 1fr;
  gap: 0.7rem;
  padding: 0.55rem 0;
  border-bottom: 1px solid var(--line);
  font-size: 0.95rem;
}

.dl dt {
  color: var(--cyan);
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
}

.dl dd {
  margin: 0;
  color: var(--muted);
}

.notebooks {
  display: grid;
  gap: 0;
  border-top: 1px solid var(--line);
}

.nb {
  display: block;
  background: transparent;
  border: 0;
  border-bottom: 1px solid var(--line);
  border-radius: 0;
  padding: 0.95rem 0;
  color: var(--text);
  text-decoration: none;
}

.nb:hover {
  border-color: var(--line);
  text-decoration: none;
}

.nb strong {
  color: var(--heading);
  font-weight: 600;
}

.nb span {
  display: block;
  color: var(--muted);
  font-size: 0.88rem;
  margin-top: 0.2rem;
}

footer {
  max-width: var(--lab-max);
  margin-top: 4.5rem;
  padding-top: 1.2rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.82rem;
  font-family: var(--mono);
}

@media (max-width: 900px) {
  html {
    scroll-padding-top: 7.2rem;
  }

  #syllabus,
  section[id] {
    scroll-margin-top: 7.2rem;
  }

  .github-top-right {
    top: 0.55rem;
    right: 0.65rem;
    font-size: 0.64rem;
    padding: 0.32rem 0.54rem;
  }

  .nav {
    padding: 0.62rem 0.72rem 0.5rem;
  }

  .nav-title {
    margin: 0.14rem 0 0.4rem;
  }

  .nav a {
    font-size: 0.74rem;
    padding: 0.28rem 0.52rem;
  }

  main {
    padding: 7.7rem 1rem 4rem;
  }

  .tax-card,
  .dl div,
  .slider-row {
    grid-template-columns: 1fr;
  }

  /* Keep four-way comparison visible: 2×2, not a single stack */
  .grid-4 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .grid-3 {
    grid-template-columns: 1fr;
  }

  .tabs {
    width: 100%;
  }

  .tabs button {
    flex: 1;
    padding: 0.45rem 0.4rem;
    font-size: 0.65rem;
  }
}

@media (min-width: 1100px) {
  .grid-4 {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

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

/* —— Theme, teaching chrome, print —— */

html[data-theme="light"] {
  --bg: #f6f1e8;
  --bg-elev: #efe7da;
  --bg-card: #fffaf2;
  --lab: #f1e9dd;
  --line: #dccfbc;
  --line-strong: #c6b499;
  --cyan: #0891b2;
  --cyan-dim: rgba(8, 145, 178, 0.1);
  --cyan-glow: rgba(8, 145, 178, 0.22);
  --text: #2f2418;
  --heading: #23180e;
  --muted: #6b5a47;
  --silver: #4f3f2d;
  --warn: #b45309;
  --unk: #e11d48;
  --ok: #059669;
}

html[data-theme="light"] textarea,
html[data-theme="light"] input[type="text"],
html[data-theme="light"] select,
html[data-theme="light"] .pane,
html[data-theme="light"] .tabs button:not([aria-selected="true"]),
html[data-theme="light"] .merge-log {
  background: #ffffff;
  color: var(--heading);
}

.nav-tools {
  margin-top: 1.25rem;
}

.font-note {
  font-size: 0.82rem;
  color: var(--muted);
  font-family: var(--mono);
}

.diagram-link {
  margin: 0.85rem 0 0;
  font-size: 0.88rem;
  color: var(--muted);
  font-family: var(--mono);
}

.diagram-link a {
  color: var(--cyan);
}

.exit-ticket {
  margin: 1.4rem 0 0;
  padding: 0.7rem 0.9rem;
  border: 1px dashed var(--line-strong);
  border-radius: 4px;
  font-size: 0.9rem;
  color: var(--muted);
  background: var(--cyan-dim);
}

.exit-ticket strong {
  color: var(--heading);
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  display: block;
  margin-bottom: 0.25rem;
}

.predict-prompt {
  margin: 0.6rem 0;
  padding: 0.65rem 0.8rem;
  border: 1px solid var(--warn);
  color: var(--heading);
  font-size: 0.9rem;
  background: transparent;
}

.chips.is-hidden,
.grid-3.is-hidden {
  display: none;
}

.decode-line {
  margin: 0.55rem 0 0.2rem;
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--ok);
}

.slider-hint,
.corpus-note {
  margin: 0.25rem 0 0.6rem;
  font-size: 0.8rem;
  color: var(--muted);
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.6rem;
  margin: 0.8rem 0 1.4rem;
}

.quiz {
  margin-top: 1rem;
  padding-top: 0.85rem;
  border-top: 1px solid var(--line-strong);
}

.quiz-q {
  margin: 0 0 0.45rem;
  font-size: 0.9rem;
  color: var(--heading);
}

.quiz-opt {
  display: block;
  font-family: var(--sans);
  font-size: 0.88rem;
  letter-spacing: 0;
  text-transform: none;
  color: var(--text);
  margin: 0.25rem 0;
  cursor: pointer;
}

.quiz-feedback {
  margin: 0.5rem 0 0;
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--muted);
}

.quiz-feedback[data-tone="ok"] {
  color: var(--ok);
}

.quiz-feedback[data-tone="bad"] {
  color: var(--unk);
}

.glossary dt code {
  color: var(--cyan);
}

/* —— Beginner on-ramp, algorithm steps, corrections, stats —— */

section h4 {
  margin: 1.5rem 0 0.45rem;
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  font-weight: 500;
  color: var(--cyan);
}

section ul {
  margin: 0 0 1.05rem;
  padding-left: 1.15rem;
}

section ul li {
  margin-bottom: 0.4rem;
}

.plain {
  margin: 1.9rem 0 0;
  padding: 1rem 1.15rem 0.35rem;
  border: 1px solid var(--line-strong);
  border-left: 3px solid var(--cyan);
  border-radius: var(--radius);
  background: var(--bg-card);
  box-shadow: var(--shadow-1);
}

.plain > strong {
  display: block;
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--cyan);
  margin-bottom: 0.55rem;
}

.plain p {
  font-size: 0.96rem;
  color: var(--muted);
  max-width: 62ch;
}

.plain-path {
  font-family: var(--mono);
  font-size: 0.82rem;
  line-height: 1.9;
}

.steps {
  counter-reset: step;
  list-style: none;
  margin: 1.2rem 0 1.6rem;
  padding: 0;
  border-top: 1px solid var(--line);
}

.steps li {
  counter-increment: step;
  position: relative;
  margin: 0;
  padding: 0.75rem 0 0.75rem 2.6rem;
  border-bottom: 1px solid var(--line);
  font-size: 0.96rem;
  color: var(--muted);
}

.steps li::before {
  content: counter(step, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: 0.85rem;
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  color: var(--cyan);
}

.steps strong {
  color: var(--heading);
  font-weight: 600;
}

.fix-note {
  margin: 1.4rem 0 1.6rem;
  padding: 0.9rem 1.1rem 0.35rem;
  border: 1px solid var(--warn);
  border-left: 3px solid var(--warn);
  border-radius: var(--radius);
  background: rgba(180, 83, 9, 0.05);
}

.fix-note > strong {
  display: block;
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--warn);
  margin-bottom: 0.5rem;
}

.fix-note p {
  font-size: 0.93rem;
  color: var(--muted);
}

.stat-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 1px;
  margin: 1.3rem 0 1.2rem;
  background: var(--line);
  border: 1px solid var(--line);
}

.stat {
  background: var(--bg-card);
  padding: 0.85rem 0.9rem;
}

.stat strong {
  display: block;
  font-family: var(--mono);
  font-size: 1.25rem;
  font-weight: 500;
  letter-spacing: -0.02em;
  color: var(--cyan);
  line-height: 1.2;
}

.stat span {
  display: block;
  margin-top: 0.3rem;
  font-size: 0.8rem;
  line-height: 1.5;
  color: var(--muted);
}

section > .merge-log {
  min-height: 0;
  max-height: none;
}

/* —— Round-trip flow diagram —— */

.flow-figure {
  margin: 1.5rem 0 1.6rem;
  padding: 1.05rem 1.15rem 0.9rem;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--bg-card);
  box-shadow: var(--shadow-1);
}

.flow-figure figcaption {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 0.9rem;
}

.flow {
  list-style: none;
  margin: 0;
  padding: 0 0 0 1.5rem;
  position: relative;
}

/* Continuous rail behind the step markers */
.flow::before {
  content: "";
  position: absolute;
  left: 0.31rem;
  top: 1.05rem;
  bottom: 1.05rem;
  width: 1px;
  background: var(--line-strong);
}

.flow-step {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 8.5rem) minmax(0, 1fr);
  gap: 0.2rem 0.9rem;
  align-items: baseline;
  margin: 0;
  padding: 0.42rem 0.7rem;
  border: 1px solid var(--line);
  border-radius: 5px;
  background: var(--bg-elev);
}

.flow-step + .flow-step {
  margin-top: 0.2rem;
}

/* Marker sitting on the rail */
.flow-step::before {
  content: "";
  position: absolute;
  left: -1.5rem;
  top: 0.75rem;
  width: 0.63rem;
  height: 0.63rem;
  border-radius: 50%;
  background: var(--bg-card);
  border: 1px solid var(--line-strong);
}

.flow-name {
  font-family: var(--mono);
  font-size: 0.76rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--silver);
}

.flow-eg {
  font-size: 0.8rem;
  line-height: 1.5;
  color: var(--muted);
}

/* Human-readable ends — warm amber */
.flow-step.is-human {
  background: #fdf1e0;
  border-color: #d9a441;
}

.flow-step.is-human .flow-name {
  color: #92400e;
}

.flow-step.is-human::before {
  background: #b45309;
  border-color: #b45309;
}

/* The tokenizer, both times — cyan, the bridge */
.flow-step.is-tok {
  background: #e2f2f6;
  border-color: var(--cyan);
}

.flow-step.is-tok .flow-name {
  color: #0b6d85;
}

.flow-step.is-tok::before {
  background: var(--cyan);
  border-color: var(--cyan);
}

/* The model itself — indigo */
.flow-step.is-model {
  background: #eceafb;
  border-color: #4338ca;
}

.flow-step.is-model .flow-name {
  color: #4338ca;
}

.flow-step.is-model::before {
  background: #4338ca;
  border-color: #4338ca;
}

.flow-legend {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.35rem 1.1rem;
  margin: 0.9rem 0 0;
  font-size: 0.74rem;
  color: var(--muted);
}

.key {
  display: inline-block;
  width: 0.7rem;
  height: 0.7rem;
  border-radius: 2px;
  margin-right: 0.1rem;
  vertical-align: -0.05rem;
  border: 1px solid var(--line-strong);
}

.key-human {
  background: #fdf1e0;
  border-color: #d9a441;
}

.key-tok {
  background: #e2f2f6;
  border-color: var(--cyan);
}

.key-num {
  background: var(--bg-elev);
  border-color: var(--line);
}

.key-model {
  background: #eceafb;
  border-color: #4338ca;
}

@media (max-width: 700px) {
  .flow-step {
    grid-template-columns: 1fr;
    gap: 0.1rem;
  }
}

@media print {
  .nav,
  .nav-tools,
  .skip,
  .preset,
  button,
  .tabs,
  .sp-modes {
    display: none !important;
  }

  .app {
    display: block;
  }

  main {
    padding: 0;
  }

  body {
    background: #fff;
    color: #111;
    font-size: 11pt;
  }

  a {
    color: #111;
    text-decoration: underline;
  }

  .lab {
    background: #fff;
    border: 1px solid #ccc;
  }

  .exit-ticket {
    border-style: solid;
  }

  section {
    break-inside: avoid;
  }
}