@charset "UTF-8";
:root {
  --paper: #f6f5ee;
  --sage: #e4e9dd;
  --sage-light: #edf0e7;
  --ink: #253b32;
  --muted: #52614f;
  --line: #cbd2c4;
  --accent: #47674d;
  --figure-grid: #84977d;
  --sidebar: 17rem;
  --header: 76px;
  --mono: 'Cascadia Code', 'SFMono-Regular', Consolas, monospace;
  --sans: 'Segoe UI', Arial, sans-serif;
  --serif: Georgia, 'Times New Roman', serif;
}
.lesson-figure.is-data-study > :not(.figure-topline):not(.data-study) {
  display: none !important;
}
.data-study {
  --data-park: #bfd19d;
  --data-shadow: #354f47;
  --data-sun: #e9c778;
  min-width: 0;
  container-type: inline-size;
}
.data-spatial > * {
  min-width: 0;
}
@container (min-width: 520px) {
  .data-study-lists .data-spatial {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    align-items: center;
  }
  .data-study-lists .data-tree-branches {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}
.data-study .data-view {
  width: 100%;
  height: auto;
  max-height: none;
  overflow: hidden;
  touch-action: none;
}
.data-study .data-hint,
.data-study .data-note {
  font-size: 0.9375rem;
  line-height: 1.65;
  color: var(--muted);
}
.data-study .data-hint {
  text-align: center;
  margin: 0 0 1.5rem;
}
.data-study .dimension-controls {
  margin: 1.25rem 0;
}
.data-study [data-options] {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}
.data-select {
  flex: 1 1 10rem;
  min-width: 0;
  margin: 0.75rem 0;
}
.data-select label {
  display: block;
  margin-bottom: 0.5rem;
  font-size: 1rem;
}
.data-select select {
  width: 100%;
  min-height: 44px;
  padding: 0.65rem;
  border: 1px solid var(--line);
  background: var(--paper);
}
.data-study [data-extra] > .dimension-control {
  margin: 1.25rem 0;
}
.data-study .data-primary {
  border-top: 1px solid var(--line);
  padding-top: 1.5rem;
  margin-top: 1.5rem;
}
.data-primary > span {
  display: block;
  font: 0.9375rem var(--mono);
  margin-bottom: 0.75rem;
}
.data-primary > strong {
  display: block;
  font-size: clamp(1.4rem, 2vw, 2rem);
  font-weight: 600;
  overflow-wrap: anywhere;
}
.data-primary small {
  font-size: 1rem;
  font-weight: 400;
}
.data-primary p {
  font-size: 1rem;
  line-height: 1.6;
  overflow-wrap: anywhere;
}
.data-donut {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  flex-wrap: wrap;
  border-top: 1px solid var(--line);
  padding-top: 1.25rem;
}
.data-donut svg {
  width: 8rem;
  flex: 0 0 8rem;
}
.data-donut p {
  flex: 1 1 10rem;
  font-size: 1rem;
  line-height: 1.6;
}
.data-bars {
  display: grid;
  gap: 0.5rem;
}
.data-bars button {
  position: relative;
  isolation: isolate;
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  min-height: 44px;
  background: transparent;
  border: 1px solid var(--line);
  padding: 0.65rem;
  text-align: left;
  font-size: 1rem;
}
.data-bars button::before {
  content: '';
  position: absolute;
  inset: 0 auto 0 0;
  width: var(--bar-width);
  background: var(--accent);
  opacity: 0.1;
  z-index: -1;
}
.data-bars button[aria-pressed='true'] {
  border: 2px solid var(--accent);
}
.data-tree-root {
  display: flex;
  justify-content: center;
  padding-bottom: 1rem;
  position: relative;
}
.data-tree-root::after {
  content: '';
  position: absolute;
  height: 1rem;
  bottom: 0;
  left: 50%;
  border-left: 1px solid var(--line);
}
.data-tree-branches {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.75rem;
  border-top: 1px solid var(--line);
  padding-top: 1rem;
}
.data-tree-cells {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(5rem, 1fr));
  gap: 0.5rem;
}
.data-study [data-tree-pick] {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.2rem;
  background: transparent;
  border: 1px solid var(--line);
  padding: 0.4rem 0.25rem;
  font-size: 0.875rem;
  min-width: 0;
}
.data-study [data-tree-pick][aria-pressed='true'] {
  border-color: var(--accent);
  box-shadow: inset 0 -3px var(--accent);
}
.data-circle {
  display: grid;
  place-items: center;
  width: 2rem;
  height: 2rem;
  border: 1px solid var(--accent);
  border-radius: 50%;
}
[aria-pressed='true'] > .data-circle {
  color: var(--paper);
  background: var(--accent);
}
.data-tree-root button {
  min-width: 9rem !important;
}
.data-addresses {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  border-top: 1px solid var(--line);
  padding-top: 1.5rem;
  margin-top: 1.5rem;
  font-size: 0.9375rem;
}
.data-addresses code {
  display: block;
  padding-top: 0.6rem;
}
.data-study code {
  overflow-wrap: anywhere;
}
@media (max-width: 440px) {
  .data-addresses {
    grid-template-columns: 1fr;
  }
  .data-tree-branches {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}
* {
  box-sizing: border-box;
}
html {
  scroll-behavior: smooth;
  scroll-padding-top: 104px;
}
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 1.125rem;
  -webkit-font-smoothing: antialiased;
}
button,
input,
textarea,
select {
  font: inherit;
  color: inherit;
}
button,
a,
input,
textarea,
select {
  -webkit-tap-highlight-color: transparent;
}
button,
a {
  touch-action: manipulation;
}
button {
  cursor: pointer;
}
a {
  color: inherit;
  text-decoration: none;
}
button {
  background: none;
  border: 0;
}
button:hover,
a:hover {
  color: #0a2516;
}
button:focus-visible,
a:focus-visible,
svg:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 5px;
}
input:focus-visible,
textarea:focus-visible,
select:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}
h1,
h2,
h3,
p {
  margin: 0;
}
p {
  line-height: 1.75;
}
button:disabled {
  cursor: default;
}
button:disabled:hover {
  color: inherit;
}
[hidden] {
  display: none !important;
}
.eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.115em;
  font: 0.875rem/1.6 var(--mono);
}
.tiny-dot {
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  flex-shrink: 0;
}
.skip-link {
  position: fixed;
  left: 18px;
  top: -70px;
  padding: 12px;
  background: var(--ink);
  color: white;
  z-index: 100;
}
.skip-link:focus {
  top: 12px;
}
.site-header {
  height: var(--header);
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 36px;
  border-bottom: 1px solid var(--line);
  background: var(--paper);
  position: sticky;
  top: 0;
  z-index: 20;
}
.brand {
  display: flex;
  gap: 12px;
  align-items: center;
}
.brand svg {
  width: 27px;
  height: 33px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.2;
}
.brand > span {
  display: flex;
  align-items: center;
  font-size: 1.4375rem;
  letter-spacing: -1px;
  gap: 18px;
}
.brand-name {
  font-size: 0.875rem;
  line-height: 1.45;
  letter-spacing: 0.015em;
  border-left: 1px solid var(--line);
  padding-left: 18px;
}
.header-nav {
  display: flex;
  align-items: center;
  gap: 35px;
  font-size: 1rem;
}
.header-nav button {
  padding: 9px 0;
}
.header-nav span {
  margin-left: 10px;
}
.menu-toggle {
  display: none;
}
.sidebar {
  position: fixed;
  top: var(--header);
  bottom: 0;
  left: 0;
  width: var(--sidebar);
  border-right: 1px solid var(--line);
  background: var(--paper);
  padding: 30px 22px 20px;
  overflow: auto;
  scrollbar-width: thin;
  z-index: 15;
}
.sidebar-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}
.sidebar-top > .eyebrow {
  text-transform: none;
  font-size: 0.875rem;
  color: var(--muted);
}
.search-trigger {
  font-size: 0.875rem;
  padding: 4px 0;
}
.search-trigger span {
  font-size: 1.125rem;
  padding-left: 5px;
}
.section-link {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: 0.5rem;
  margin: 25px 0 24px;
  font-size: 1.125rem;
}
.section-index {
  grid-column: 1 / -1;
  font: 2rem var(--serif);
  letter-spacing: -2px;
}
.section-link small {
  display: block;
  font-size: 0.875rem;
  color: var(--muted);
  margin-top: 5px;
}
.section-link > .tiny-dot {
  grid-column: 2;
  grid-row: 2;
  align-self: start;
  margin-top: 0.65rem;
  margin-left: auto;
  width: 4px;
  height: 4px;
}
.nav-group-label {
  font: 0.875rem var(--mono);
  text-transform: none;
  letter-spacing: 0.055em;
  color: var(--muted);
  margin: 24px 0 10px;
}
.lesson-nav-link {
  display: flex;
  align-items: center;
  gap: 9px;
  font-size: 1rem;
  line-height: 1.4;
  padding: 8px 9px 8px 14px;
  position: relative;
  border-left: 1px solid var(--line);
  color: var(--muted);
}
.lesson-nav-link:hover {
  background: #e9ecdf;
}
.lesson-nav-link[aria-current='location'] {
  border-left: 2px solid var(--accent);
  padding-left: 13px;
  color: var(--ink);
  background: #e4e8db;
}
.nav-check {
  margin-left: auto;
  font-size: 0.875rem;
  color: var(--accent);
}
.lab-link {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 22px 0 30px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
  font-size: 1rem;
}
.lab-link > span:last-child {
  margin-left: auto;
}
.course-progress {
  margin-top: 25px;
}
.progress-label {
  display: flex;
  justify-content: space-between;
  font-size: 0.875rem;
}
.course-progress progress {
  width: 100%;
  height: 3px;
  display: block;
  margin-top: 10px;
  border: none;
  background: #dbe0d3;
  appearance: none;
}
.course-progress progress::-webkit-progress-bar {
  background: #dbe0d3;
}
.course-progress progress::-webkit-progress-value {
  background: var(--accent);
}
.course-progress progress::-moz-progress-bar {
  background: var(--accent);
}
.course-progress p {
  font-size: 0.875rem;
  color: var(--muted);
  margin-top: 8px;
}
.about-trigger {
  font-size: 0.875rem;
  color: var(--muted);
  margin-top: 28px;
  padding: 0;
}
.about-trigger span {
  margin-left: 25px;
}
main {
  margin-left: var(--sidebar);
}
.landscape {
  height: 155vh;
  min-height: 1000px;
  background: var(--intro-background);
  border-bottom: 1px solid var(--line);
}
.landscape-sticky {
  position: sticky;
  top: var(--header);
  height: calc(100vh - var(--header));
  min-height: 620px;
  max-height: 1000px;
  padding: 30px 48px 0;
  overflow: hidden;
}
.intro-topline {
  display: flex;
  justify-content: space-between;
  color: var(--muted);
  font-size: 0.875rem;
}
.hero-body {
  display: grid;
  grid-template-columns: 0.95fr 1.15fr;
  align-items: center;
  height: calc(100% - 105px);
  max-width: 1450px;
  margin: auto;
  gap: 10px;
}
.hero-copy {
  position: relative;
  z-index: 2;
  padding: 25px 0 20px;
}
.intro-kicker {
  display: flex;
  align-items: center;
  gap: 9px;
  font-size: 0.875rem;
}
.hero-copy :is(h1, h2) {
  font-weight: 400;
  font-size: clamp(3.4375rem, 5.5vw, 5.875rem);
  line-height: 1.06;
  letter-spacing: -0.065em;
  margin: 25px 0;
}
.hero-copy :is(h1, h2) em {
  font-family: var(--serif);
  font-weight: 400;
  letter-spacing: -0.065em;
}
.hero-description {
  font-size: 1.125rem;
  line-height: 1.75;
  color: var(--muted);
}
.primary-link {
  display: inline-flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  background: var(--ink);
  color: var(--paper);
  padding: 15px 21px;
  font-size: 1rem;
  text-align: left;
  border: 1px solid var(--ink);
}
.primary-link:hover {
  background: #385240;
  color: white;
}
.hero-copy .primary-link {
  margin-top: 27px;
  min-width: 185px;
}
.hero-footnote {
  font-size: 0.875rem;
  color: var(--muted);
  margin-top: 20px;
  line-height: 1.7;
}
.hero-figure {
  align-self: center;
  position: relative;
  min-width: 0;
  padding-top: 40px;
}
.figure-topline {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  font-size: 0.875rem;
}
.hero-figure .figure-topline {
  padding: 0 10px;
  color: var(--muted);
}
.geometry-svg {
  display: block;
  width: 100%;
  height: auto;
  overflow: visible;
}
.hero-figure > .geometry-svg {
  filter: drop-shadow(0 20px 22px #5d705811);
}
.hero-figure-caption {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.875rem;
  color: var(--muted);
  padding: 0 10px;
  gap: 20px;
}
.intro-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid var(--line);
  height: 75px;
  gap: 18px;
}
.scroll-prompt {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.125rem;
}
.scroll-prompt span {
  font: 0.875rem var(--mono);
  color: var(--muted);
}
.stage-selector {
  display: flex;
  gap: 24px;
}
.stage-selector button {
  padding: 10px 0;
  font: 0.875rem var(--mono);
  position: relative;
}
.stage-selector button > span {
  font-size: 0.875rem;
  color: var(--muted);
  margin-right: 7px;
}
.stage-selector button[aria-pressed='true']::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--accent);
}
.atlas {
  padding: 64px 48px 0;
}
.section-heading {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  border-bottom: 1px solid var(--line);
  padding-bottom: 28px;
  gap: 20px;
}
.section-heading h2 {
  font-size: 2.125rem;
  font-weight: 400;
  letter-spacing: -1.5px;
  margin-top: 10px;
}
.section-heading > p {
  font-size: 1rem;
  color: var(--muted);
}
.atlas-grid {
  display: grid;
  grid-template-columns: minmax(250px, 0.85fr) minmax(330px, 1.15fr);
  gap: 42px;
}
.lesson {
  padding: 64px 0 55px;
  min-height: 610px;
  scroll-margin-top: 110px;
  border-bottom: 1px solid var(--line);
}
.lesson .lesson-number {
  font: 0.875rem var(--mono);
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}
.lesson h3 {
  font: 400 clamp(1.75rem, 2.7vw, 2.6875rem)/1.16 var(--sans);
  letter-spacing: -1.5px;
  margin: 18px 0 23px;
}
.lesson .lead {
  font-size: 1.25rem;
  color: var(--ink);
  line-height: 1.6;
  margin-bottom: 19px;
}
.lesson p {
  font-size: 1.125rem;
  color: var(--muted);
  margin-bottom: 18px;
}
.lesson strong {
  color: var(--ink);
  font-weight: 600;
}
.lesson ul,
.lesson ol {
  padding-left: 18px;
  font-size: 1.125rem;
  line-height: 1.8;
  color: var(--muted);
  margin: 0 0 20px;
}
.lesson li + li {
  margin-top: 4px;
}
.lesson .formula {
  padding: 18px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  font: 1.375rem var(--serif);
  color: var(--ink);
  margin: 25px 0;
}
.lesson .try-note {
  padding: 15px 0 15px 16px;
  border-left: 2px solid #819676;
  font-size: 1rem;
}
.try-note span {
  display: block;
  font: 0.875rem var(--mono);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent);
  margin-bottom: 6px;
}
.lesson table {
  width: 100%;
  border-collapse: collapse;
  font-size: 1rem;
  line-height: 1.65;
  margin-bottom: 20px;
}
.lesson th,
.lesson td {
  text-align: left;
  vertical-align: top;
  padding: 10px 8px;
  border-bottom: 1px solid var(--line);
}
.lesson th:first-child,
.lesson td:first-child {
  padding-left: 0;
}
.lesson th {
  font-size: 0.875rem;
}
.lesson td {
  color: var(--muted);
}
.lesson-actions {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 28px;
  gap: 12px;
}
.complete-button {
  font-size: 0.875rem;
  border: 1px solid var(--line);
  padding: 10px 12px;
  display: flex;
  gap: 8px;
  align-items: center;
}
.complete-button[aria-pressed='true'] {
  background: var(--sage);
  border-color: #a4b39a;
}
.lesson-next {
  font-size: 0.875rem;
  color: var(--muted);
}
.subsection-label {
  font: 0.875rem var(--mono);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  border-bottom: 1px solid var(--line);
  padding: 32px 0;
  color: var(--accent);
}
.figure-column {
  min-width: 0;
  padding: 42px 0;
}
.lesson-figure {
  position: sticky;
  top: 104px;
  padding: 22px;
  background: var(--sage-light);
  border: 1px solid #d7dece;
}
.live-badge {
  font-size: 0.875rem;
  text-transform: none;
  letter-spacing: 0;
  white-space: nowrap;
}
.live-badge:before {
  content: '';
  display: inline-block;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--accent);
  margin-right: 5px;
}
.figure-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 21px;
  font-size: 1rem;
}
.text-button {
  font-size: 0.875rem;
  padding: 6px 0;
}
.orbitable {
  cursor: grab;
  touch-action: pan-y;
  user-select: none;
}
.orbitable:active {
  cursor: grabbing;
}
.orbit-hint {
  text-align: center;
  font: 0.875rem var(--mono);
  color: var(--muted);
  margin: -10px 0 25px;
}
.dimension-controls {
  display: flex;
  gap: 19px;
}
.dimension-control {
  flex: 1;
  min-width: 0;
}
.dimension-control label {
  display: flex;
  justify-content: space-between;
  font-size: 0.875rem;
  gap: 6px;
  line-height: 1.5;
}
.dimension-control output {
  font: 0.875rem var(--mono);
  white-space: nowrap;
}
.dimension-control input {
  width: 100%;
  margin: 14px 0;
  accent-color: var(--accent);
  height: 3px;
  cursor: pointer;
  display: block;
}
.figure-result {
  border-top: 1px solid var(--line);
  padding-top: 20px;
  display: flex;
  align-items: center;
  gap: 15px;
}
.figure-result > output {
  font: 2rem var(--serif);
  margin-left: auto;
}
.figure-result small,
.lab-volume small {
  font: 1rem var(--sans);
}
.figure-result > span:last-child {
  font: 0.875rem var(--mono);
  color: var(--muted);
}
.figure-note {
  font-size: 0.875rem;
  line-height: 1.65;
  color: var(--muted);
  margin-top: 13px;
}
.operation-controls {
  margin: 10px 0 20px;
}
.sampling-controls {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin: 1rem 0 1.5rem;
}
.sampling-controls > div {
  min-width: 0;
}
.sampling-controls label {
  display: flex;
  justify-content: space-between;
  gap: 0.5rem;
  font-size: 1rem;
  margin-bottom: 0.5rem;
}
.sampling-controls select {
  width: 100%;
  min-height: 2.75rem;
  background: var(--paper);
  border: 1px solid var(--line);
  padding: 0.5rem;
  font-size: 1rem;
}
.sampling-controls input[type='range'] {
  width: 100%;
  min-height: 1.5rem;
  accent-color: var(--accent);
}
.is-sampling .figure-result {
  flex-wrap: wrap;
}
.is-sampling .figure-result > output {
  font-size: 1.5rem;
}
.is-sampling .figure-result > span:last-child {
  width: 100%;
}
.is-sampling .geometry-svg {
  max-height: 340px;
}
@media screen and (min-width: 701px) {
  .lesson-figure.is-sampling {
    max-height: calc(100svh - var(--header) - 2rem);
    overflow-y: auto;
    overscroll-behavior: contain;
    scrollbar-width: thin;
  }
}
[data-theme='dark'] {
  --sample-accent: #f0bd83;
}
@media (max-width: 480px) {
  .sampling-controls {
    grid-template-columns: 1fr;
  }
}
.operation-controls label {
  display: flex;
  justify-content: space-between;
  font-size: 1rem;
  margin: 12px 0;
}
.operation-controls select {
  background: var(--paper);
  border: 1px solid var(--line);
  padding: 8px;
  width: 100%;
  font-size: 1rem;
}
.operation-controls input {
  width: 100%;
  accent-color: var(--accent);
}
.concept-visual {
  min-height: 300px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 18px;
  padding: 28px 0;
}
.flow-sequence {
  color: var(--ink);
  padding: 1.5rem 0;
}
.flow-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 1em minmax(0, 1.45fr) 1em minmax(0, 1fr);
  align-items: center;
  gap: 0.3rem;
  text-align: center;
  font-size: clamp(1rem, 1.2vw, 1.375rem);
}
.flow-row span {
  padding: 0.8rem 0.2rem;
  border-block: 1px solid var(--line);
}
.flow-inline-arrow {
  width: 1em;
  height: 1em;
  overflow: visible;
  fill: none;
  stroke: var(--accent);
  stroke-width: 1.2;
  flex-shrink: 0;
}
.flow-connector {
  display: block;
  width: 100%;
  height: 4.5rem;
  overflow: visible;
  fill: none;
  stroke: var(--accent);
  stroke-width: 1.2;
}
.flow-continuation em {
  grid-column: 3;
  text-align: center;
}
.flow-pause {
  align-self: flex-start;
  min-height: 44px;
}
.workflow-status {
  border-left: 2px solid var(--accent);
  padding: 0.75rem 1rem;
  margin: 0 0 1.5rem;
  color: var(--ink);
}
.workflow-lab .workflow-workspace {
  grid-template-columns: minmax(0, 1.2fr) minmax(19rem, 0.8fr);
  align-items: start;
}
.workflow-workspace > * {
  min-width: 0;
}
.workflow-workspace .lab-viewport {
  position: sticky;
  top: 1rem;
}
.workflow-workspace .lab-topbar {
  flex-wrap: wrap;
  gap: 0.75rem;
}
.workflow-view-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1rem;
  margin-left: auto;
}
.workflow-lesson-flow {
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--line);
}
.course-about {
  padding: 32px clamp(24px, 4vw, 72px) 64px;
  background: var(--paper);
  color: var(--ink);
}
.about-intro {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(0, 0.85fr);
  align-items: center;
  gap: clamp(32px, 5vw, 80px);
  padding: 64px 0;
}
.about-copy {
  max-width: 42rem;
}
.about-copy p {
  margin: 0 0 1.25rem;
}
.about-copy .eyebrow {
  margin-bottom: 1.5rem;
}
.course-about h1 {
  font-size: clamp(2.5rem, 4vw, 4.5rem);
  line-height: 1.08;
  font-weight: 400;
  letter-spacing: -0.04em;
  margin: 0 0 1.5rem;
}
.course-about h1 em {
  font-family: var(--serif);
}
.about-lead {
  font-size: 1.375rem;
}
.about-portrait {
  margin: 0;
}
.about-portrait img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--line);
}
.about-portrait figcaption {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding-top: 0.75rem;
  font: 0.875rem var(--mono);
  color: var(--muted);
}
.about-section {
  display: grid;
  grid-template-columns: minmax(0, 0.8fr) minmax(0, 1.6fr);
  gap: 3rem;
  border-top: 1px solid var(--line);
  padding: 3rem 0;
}
.course-about h2 {
  font-size: 2rem;
  line-height: 1.2;
  font-weight: 400;
  margin: 1rem 0;
}
.about-role,
.about-meta {
  color: var(--muted);
}
.about-details {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 2rem;
}
.about-details h3 {
  font-size: 1.125rem;
  margin: 0 0 1rem;
}
.about-details p {
  margin: 0 0 1rem;
}
.about-details ul {
  margin: 0;
  padding-left: 1.25rem;
}
.about-links {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem 2rem;
}
.about-links a {
  text-decoration: underline;
  text-underline-offset: 0.25em;
  overflow-wrap: anywhere;
}
#about-page-link[aria-current='page'] {
  text-decoration: underline;
  text-underline-offset: 0.3em;
}
@media (max-width: 1000px) {
  .about-intro,
  .about-section {
    grid-template-columns: minmax(0, 1fr);
    gap: 2rem;
  }
  .about-portrait {
    max-width: 26rem;
  }
  .about-details {
    grid-template-columns: minmax(0, 1fr);
  }
}
#workflow-labels[aria-pressed='true'] {
  text-decoration: underline;
  text-underline-offset: 0.3em;
}
.workflow-workspace .geometry-svg {
  width: 100%;
  height: auto;
  max-height: 420px;
}
.workflow-step + .workflow-step {
  margin-top: 1.75rem;
  padding-top: 1.75rem;
  border-top: 1px solid var(--line);
}
.workflow-step h3 {
  margin: 0 0 0.75rem;
}
.workflow-step p {
  margin: 0.75rem 0;
}
.workflow-step label {
  display: flex;
  justify-content: space-between;
  gap: 0.75rem;
  margin-top: 1rem;
}
.workflow-step .wf-checkbox {
  justify-content: flex-start;
  align-items: flex-start;
}
.wf-checkbox input {
  margin-top: 0.4rem;
  min-width: 1.1rem;
  height: 1.1rem;
  accent-color: var(--accent);
}
.workflow-step h3:focus {
  outline: 2px solid var(--accent);
  outline-offset: 4px;
}
.workflow-step select {
  width: 100%;
  min-width: 0;
  min-height: 44px;
  margin-top: 0.5rem;
  padding: 0.5rem;
  color: var(--ink);
  background: var(--paper);
  border: 1px solid var(--line);
  font: inherit;
}
.workflow-step input[type='range'] {
  width: 100%;
  min-height: 28px;
  accent-color: var(--accent);
}
.workflow-step .complete-button {
  margin-top: 1rem;
  min-height: 44px;
}
.workflow-step button:disabled {
  opacity: 0.5;
  cursor: default;
}
.workflow-axes {
  display: flex;
  gap: 0.5rem;
}
.workflow-axes button {
  flex: 1;
  min-height: 44px;
  border: 1px solid var(--line);
  color: var(--ink);
  background: transparent;
}
.workflow-axes button[aria-pressed='true'],
#workflow-close[aria-pressed='true'] {
  border-color: var(--accent);
  box-shadow: inset 0 -3px var(--accent);
}
.workflow-metrics {
  border-top: 1px solid var(--line);
  padding-top: 0.75rem;
  overflow-wrap: anywhere;
}
.workflow-metrics p {
  margin: 0.4rem 0;
}
.workflow-recipe {
  border-top: 1px solid var(--line);
  margin-top: 1rem;
  padding-top: 1rem;
  line-height: 1.8;
  color: var(--ink);
}
@media (max-width: 1200px) {
  .workflow-lab .workflow-workspace {
    grid-template-columns: minmax(0, 1fr);
  }
  .workflow-workspace .lab-viewport {
    position: static;
  }
}
.cad-computer {
  --cad-frame: var(--ink);
  --cad-border: var(--muted);
  --cad-detail: var(--muted);
  width: 100%;
  height: auto;
}
[data-theme='dark'] .cad-computer {
  --cad-frame: #f2f2f2;
  --cad-border: #e8e8e8;
  --cad-detail: #d9d9d9;
  --cad-toolbar: #293f3dff;
  --cad-toolbar-opacity: 1;
}
.concept-visual .node {
  border: 1px solid #aabb9e;
  padding: 16px;
  background: #e3e9d9;
  font-size: 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
}
.node small {
  font: 0.875rem var(--mono);
  color: var(--muted);
}
.flow-arrow {
  text-align: center;
  font-size: 1.125rem;
  color: var(--muted);
}
.concept-caption {
  font-size: 1rem;
  color: var(--muted);
  line-height: 1.6;
  text-align: center;
}
.geometry-lab {
  background: #e2e8da;
  border-top: 1px solid var(--line);
  padding: 64px 48px;
  scroll-margin-top: 76px;
}
.lab-heading {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  gap: 20px;
  margin-bottom: 35px;
}
.lab-heading .eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
}
.lab-heading h2 {
  font-size: 2.5625rem;
  font-weight: 400;
  letter-spacing: -1.8px;
  margin-top: 15px;
}
.lab-heading > p {
  font-size: 1rem;
  color: var(--muted);
}
.lab-workspace {
  display: grid;
  grid-template-columns: 1fr 220px;
  border: 1px solid #bac6ae;
}
.lab-viewport {
  padding: 20px 24px;
  background: #eaf0e1;
  min-width: 0;
}
.lab-topbar,
.lab-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
}
.shape-selector,
.view-selector {
  display: flex;
  gap: 3px;
}
.shape-selector button,
.view-selector button {
  font-size: 0.875rem;
  padding: 8px 10px;
  border: 1px solid transparent;
}
.shape-selector button[aria-pressed='true'],
.view-selector button[aria-pressed='true'] {
  border-color: #aebd9f;
  background: #dce5d1;
}
.lab-viewport > .geometry-svg {
  max-height: 450px;
}
.lab-parameters {
  border-left: 1px solid #bac6ae;
  padding: 25px 22px;
}
.lab-parameters > .eyebrow {
  font-size: 0.875rem;
}
.lab-parameters h3 {
  font-size: 1.125rem;
  font-weight: 400;
  margin: 15px 0 28px;
}
.lab-parameters .dimension-controls {
  flex-direction: column;
  gap: 18px;
}
.lab-volume {
  border-top: 1px solid #bac6ae;
  margin-top: 28px;
  padding-top: 20px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.lab-volume output {
  font: 2.875rem var(--serif);
  letter-spacing: -1px;
  overflow-wrap: anywhere;
}
.lab-volume > span:last-child {
  font: 1rem var(--mono);
  color: var(--muted);
}
.lab-help {
  font-size: 1rem;
  color: var(--muted);
  margin-top: 23px;
}
.challenge {
  display: grid;
  grid-template-columns: 1.3fr 1fr;
  gap: 60px;
  border-top: 1px solid #bac6ae;
  margin-top: 32px;
  padding-top: 28px;
}
.challenge h3 {
  font: 1.6875rem var(--serif);
  letter-spacing: -0.8px;
  margin: 10px 0;
}
.challenge p {
  font-size: 1rem;
  color: var(--muted);
}
.challenge-action {
  align-self: center;
}
.challenge-action p {
  font-size: 1rem;
  margin-top: 13px;
}
.challenge-action p.success {
  color: #244b2c;
}
.site-footer {
  padding: 56px 48px;
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  gap: 30px;
}
.exercise-navigation,
.extraction-tasks {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin: 0 0 1.5rem;
}
.exercise-navigation a {
  font-size: 1rem;
  padding: 0.5rem 0;
  margin-right: 1rem;
  border-bottom: 1px solid var(--line);
}
.extraction-tasks button {
  flex: 1 1 11rem;
  text-align: left;
  border: 1px solid var(--line);
  padding: 0.875rem 1rem;
  font-size: 1rem;
  background: var(--paper);
}
.extraction-tasks button[aria-pressed='true'] {
  border-color: var(--accent);
  box-shadow: inset 0 3px var(--accent);
}
.task-status {
  display: block;
  margin-top: 0.5rem;
  font-size: 0.875rem;
  color: var(--muted);
}
.extraction-prompt {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 1.5rem;
}
.extraction-prompt > div {
  flex: 1 1 22rem;
  min-width: 0;
}
.extraction-prompt h3 {
  font: 1.625rem/1.4 var(--serif);
  margin: 0.5rem 0;
}
.extraction-prompt p:not(.eyebrow) {
  max-width: 70ch;
}
.extraction-lab .extraction-workspace {
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 20rem), 1fr));
}
.extraction-workspace > * {
  min-width: 0;
}
.extraction-workspace .sampling-controls {
  grid-template-columns: 1fr;
}
.extraction-workspace .lab-parameters h3 {
  margin: 0 0 1rem;
}
.extraction-workspace .lab-topbar {
  flex-wrap: wrap;
}
.extraction-readout {
  display: grid;
  gap: 0.5rem;
  border-top: 1px solid var(--line);
  padding-top: 1rem;
}
.extraction-readout output {
  font: 1.625rem var(--serif);
}
.extraction-readout > span:last-child {
  font: 0.875rem/1.6 var(--mono);
  color: var(--muted);
}
.extraction-check {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  gap: 1.25rem;
  margin: 1.5rem 0;
}
.extraction-check button {
  max-width: 100%;
  white-space: normal;
}
.extraction-check p {
  flex: 1 1 24rem;
  min-width: 0;
}
.extraction-check .success {
  font-weight: 600;
}
.extraction-progress {
  border-top: 1px solid var(--line);
  padding-top: 1.25rem;
}
.extraction-progress label {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem;
}
.extraction-progress progress {
  display: block;
  width: 100%;
  height: 0.5rem;
  accent-color: var(--accent);
  margin: 1rem 0;
}
.extraction-progress p {
  font-size: 1rem;
  color: var(--muted);
}
@media (max-width: 1100px) {
  .extraction-lab .extraction-workspace {
    grid-template-columns: minmax(0, 1fr);
  }
  .extraction-workspace .lab-parameters {
    border-left: 0;
    border-top: 1px solid var(--line);
  }
}
@media print {
  .extraction-tasks,
  .extraction-check,
  .extraction-progress,
  .extraction-prompt > button {
    display: none;
  }
}
.footer-title {
  font-size: 2.1875rem;
  line-height: 1.15;
  letter-spacing: -1.6px;
}
.footer-title em {
  font-family: var(--serif);
}
.site-footer > div:last-child > p:not(.eyebrow) {
  font-size: 0.875rem;
  color: var(--muted);
  margin-top: 9px;
}
.site-footer a {
  font-size: 0.875rem;
  display: inline-block;
  margin-top: 20px;
  border-bottom: 1px solid var(--line);
  padding-bottom: 4px;
}
dialog {
  width: min(570px, calc(100% - 32px));
  max-height: 85vh;
  padding: 30px;
  background: var(--paper);
  color: var(--ink);
  border: 1px solid var(--line);
  box-shadow: 0 25px 100px #15271926;
}
dialog::backdrop {
  background: #192d245c;
  backdrop-filter: blur(4px);
}
.dialog-heading {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 20px;
  margin-bottom: 22px;
}
.dialog-heading h2 {
  font: 2rem var(--serif);
  letter-spacing: -1px;
}
.dialog-heading button {
  font-size: 1.625rem;
  line-height: 1;
  padding: 4px;
}
dialog p {
  font-size: 1.125rem;
  color: var(--muted);
  margin-bottom: 20px;
}
dialog label {
  display: block;
  margin-bottom: 10px;
}
dialog input[type='search'],
dialog textarea {
  border: 1px solid var(--line);
  background: #edf0e5;
  padding: 13px;
  width: 100%;
  font-size: 1.125rem;
  border-radius: 0;
}
dialog textarea {
  resize: vertical;
  line-height: 1.7;
  min-height: 160px;
}
.search-results {
  margin-top: 16px;
  max-height: 43vh;
  overflow: auto;
}
.search-result {
  display: block;
  padding: 13px 5px;
  border-bottom: 1px solid var(--line);
  font-size: 1.125rem;
}
.search-result small {
  display: block;
  font: 0.875rem var(--mono);
  color: var(--muted);
  margin-top: 6px;
}
.notebook-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 18px;
  margin-top: 14px;
}
.notebook-bottom span {
  font-size: 0.875rem;
  color: var(--muted);
}
.noscript {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  padding: 18px;
  background: var(--ink);
  color: white;
  z-index: 50;
}
.noscript a {
  text-decoration: underline;
}
@media (min-width: 1700px) {
  :root {
    --sidebar: 18rem;
  }
  .landscape-sticky,
  .atlas,
  .geometry-lab,
  .site-footer {
    padding-left: 75px;
    padding-right: 75px;
  }
  .atlas-grid {
    gap: 80px;
  }
  .lesson {
    min-height: 690px;
  }
  .lesson-figure {
    max-width: 720px;
  }
  .sidebar {
    padding-left: 28px;
    padding-right: 28px;
  }
}
@media (max-height: 850px) and (min-width: 1001px) {
  .sidebar {
    padding-top: 20px;
  }
  .section-link {
    margin: 18px 0;
  }
  .nav-group-label {
    margin: 18px 0 8px;
  }
  .lesson-nav-link {
    padding-top: 6px;
    padding-bottom: 6px;
  }
  .lab-link {
    margin-bottom: 18px;
  }
  .course-progress {
    margin-top: 15px;
  }
  .about-trigger {
    margin-top: 16px;
  }
  .landscape-sticky {
    min-height: 570px;
  }
  .lesson-figure {
    padding: 18px;
    top: 92px;
  }
  .lesson-figure > .geometry-svg {
    max-height: 280px;
  }
  .concept-visual {
    min-height: 260px;
  }
  .orbit-hint {
    margin-bottom: 20px;
  }
  .figure-result {
    padding-top: 14px;
  }
  .figure-note {
    margin-top: 9px;
  }
}
@media (max-width: 1200px) {
  :root {
    --sidebar: 16rem;
  }
  .sidebar {
    padding-left: 17px;
    padding-right: 17px;
  }
  .landscape-sticky {
    padding-left: 30px;
    padding-right: 30px;
  }
  .atlas,
  .geometry-lab,
  .site-footer {
    padding-left: 30px;
    padding-right: 30px;
  }
  .atlas-grid {
    gap: 25px;
    grid-template-columns: minmax(220px, 0.9fr) minmax(285px, 1.1fr);
  }
  .stage-selector {
    gap: 15px;
  }
  .scroll-prompt span {
    max-width: 100px;
    line-height: 1.5;
  }
  .hero-copy :is(h1, h2) {
    font-size: 4.0625rem;
  }
  .hero-figure {
    padding-top: 55px;
  }
  .dimension-controls {
    gap: 10px;
  }
  .figure-result {
    gap: 8px;
  }
  .figure-result > span:last-child {
    font-size: 0.875rem;
  }
  .lab-workspace {
    grid-template-columns: 1fr 190px;
  }
  .lab-parameters {
    padding: 22px 17px;
  }
  .shape-selector button {
    padding: 7px;
  }
  .lab-viewport {
    padding: 17px;
  }
  .figure-topline {
    font-size: 0.875rem;
  }
  .hero-description {
    font-size: 1rem;
  }
}
@media (max-width: 1000px) {
  :root {
    --header: 66px;
    --sidebar: 0px;
  }
  .site-header {
    padding: 0 24px;
  }
  .sidebar {
    width: 260px;
    transform: translateX(-100%);
    transition: transform 0.2s;
    box-shadow: 15px 0 40px #253b3212;
  }
  .sidebar.is-open {
    transform: translateX(0);
  }
  .menu-toggle {
    display: block;
    font-size: 1rem;
  }
  .menu-toggle span {
    margin-left: 9px;
  }
  .header-nav {
    gap: 20px;
    margin-left: auto;
    margin-right: 30px;
  }
  .brand-name {
    display: none;
  }
  .hero-copy :is(h1, h2) {
    font-size: clamp(3.5625rem, 8vw, 5rem);
  }
  .landscape-sticky {
    min-height: 570px;
  }
  .lesson-figure {
    top: 90px;
  }
  .atlas-grid {
    grid-template-columns: minmax(260px, 1fr) minmax(330px, 1.1fr);
    gap: 30px;
  }
}
@media (max-width: 700px) {
  html {
    scroll-padding-top: 85px;
  }
  .site-header {
    padding: 0 18px;
  }
  .brand > span {
    font-size: 1.25rem;
  }
  .brand svg {
    width: 24px;
  }
  .header-nav {
    gap: 16px;
    margin-right: 22px;
    font-size: 0.875rem;
  }
  .header-nav a[href='#space'] {
    display: none;
  }
  .header-nav span {
    display: none;
  }
  .header-nav button {
    font-size: 0.875rem;
  }
  .menu-toggle {
    font-size: 0.875rem;
  }
  .hero-copy :is(h1, h2) {
    font-size: 3.875rem;
  }
  .landscape {
    height: auto;
    min-height: 0;
  }
  .landscape-sticky {
    position: relative;
    top: auto;
    height: auto;
    min-height: 0;
    max-height: none;
    padding: 24px 24px 0;
  }
  .intro-topline {
    font-size: 0.875rem;
    gap: 14px;
  }
  .intro-topline > span:first-child {
    max-width: 115px;
  }
  .hero-body {
    display: flex;
    flex-direction: column;
    gap: 0;
    align-items: stretch;
  }
  .hero-copy {
    padding: 42px 0 0;
  }
  .intro-kicker {
    font-size: 0.875rem;
  }
  .hero-copy :is(h1, h2) {
    margin: 20px 0;
  }
  .hero-description {
    font-size: 1.125rem;
  }
  .hero-copy .primary-link {
    margin-top: 22px;
    padding: 13px 17px;
  }
  .hero-footnote {
    position: absolute;
    right: 0;
    bottom: 0;
    font-size: 0.875rem;
    text-align: right;
  }
  .hero-figure {
    padding-top: 37px;
    width: 100%;
    max-width: 480px;
    margin: 0 auto;
  }
  .hero-figure > .geometry-svg {
    margin-top: -10px;
    margin-bottom: -15px;
    max-height: 310px;
  }
  .hero-figure-caption {
    font-size: 0.875rem;
    padding: 0;
  }
  .intro-bottom {
    margin-top: 25px;
    height: auto;
    padding: 17px 0;
    display: block;
  }
  .scroll-prompt {
    display: none;
  }
  .stage-selector {
    justify-content: space-between;
    gap: 8px;
  }
  .stage-selector button {
    font-size: 0.875rem;
  }
  .stage-selector button > span {
    font-size: 0.875rem;
    margin-right: 4px;
  }
  .atlas {
    padding: 42px 24px 0;
  }
  .section-heading h2 {
    font-size: 1.8125rem;
  }
  .section-heading > p {
    display: none;
  }
  .atlas-grid {
    display: flex;
    flex-direction: column;
    gap: 0;
  }
  .lesson {
    min-height: 0;
    padding: 38px 0;
  }
  .lesson h3 {
    font-size: 2rem;
  }
  .lesson p {
    font-size: 1rem;
  }
  .lesson .lead {
    font-size: 1.25rem;
  }
  .figure-column {
    order: -1;
    padding: 22px 0 0;
  }
  .lesson-figure {
    position: relative;
    top: 0;
  }
  .lesson-figure > .geometry-svg {
    max-height: 245px;
  }
  .lesson-figure.mobile-active {
    margin: 22px 0;
  }
  .concept-visual {
    min-height: 250px;
  }
  .orbit-hint {
    margin-top: 0;
  }
  .lesson-actions {
    margin-top: 22px;
  }
  .geometry-lab {
    padding: 40px 24px;
  }
  .lab-heading h2 {
    font-size: 2rem;
  }
  .lab-heading > p {
    display: none;
  }
  .lab-workspace {
    grid-template-columns: 1fr;
  }
  .lab-viewport {
    padding: 15px;
  }
  .lab-parameters {
    border-left: 0;
    border-top: 1px solid #bac6ae;
    padding: 22px;
  }
  .lab-parameters .dimension-controls {
    flex-direction: row;
    gap: 20px;
  }
  .lab-parameters h3 {
    margin: 10px 0 20px;
  }
  .lab-volume {
    flex-direction: row;
    align-items: baseline;
    gap: 15px;
    margin-top: 16px;
    padding-top: 18px;
  }
  .lab-volume output {
    font-size: 2.1875rem;
    margin-left: auto;
  }
  .lab-volume > span:last-child {
    display: none;
  }
  .lab-help {
    margin-top: 14px;
  }
  .lab-bottom {
    gap: 5px;
  }
  .view-selector button {
    font-size: 0.875rem;
    padding: 6px;
  }
  .challenge {
    grid-template-columns: 1fr;
    gap: 20px;
  }
  .site-footer {
    padding: 38px 24px;
    flex-direction: column;
    align-items: flex-start;
  }
  .footer-title {
    font-size: 2.0625rem;
  }
  .notebook-bottom {
    align-items: flex-start;
  }
  dialog {
    padding: 24px;
  }
  .dialog-heading h2 {
    font-size: 1.75rem;
  }
}
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *,
  *::before,
  *::after {
    animation: none !important;
    transition: none !important;
  }
  .landscape {
    height: auto;
    min-height: 0;
  }
  .landscape-sticky {
    position: relative;
    top: 0;
    height: auto;
    min-height: 650px;
  }
  .hero-body {
    min-height: 500px;
  }
  .scroll-prompt span {
    font-size: 0;
  }
  .scroll-prompt span::after {
    content: 'Explore each dimension';
    font-size: 0.875rem;
  }
}
@media print {
  .site-header,
  .sidebar,
  .landscape,
  .figure-column,
  .lesson-actions,
  .lab-workspace,
  .challenge-action,
  dialog,
  .skip-link {
    display: none !important;
  }
  main {
    margin: 0;
  }
  .atlas {
    padding: 0;
  }
  .atlas-grid {
    display: block;
  }
  .lesson {
    min-height: 0;
    break-inside: avoid;
    padding: 20px 0;
  }
  .geometry-lab,
  .site-footer {
    background: white;
    padding: 20px 0;
  }
  .lab-heading {
    margin: 0;
  }
  .challenge {
    display: block;
  }
  body {
    color: #111;
    background: white;
  }
}

.mobile-explore {
  display: none;
}
@media (max-width: 700px) {
  .mobile-explore {
    display: inline-flex;
    margin-top: 4px;
  }
  .lesson-figure {
    scroll-margin-top: 90px;
  }
}

@media (min-width: 701px) {
  .lesson-figure {
    max-height: calc(100dvh - 120px);
    overflow-y: auto;
    scrollbar-width: thin;
  }
}
@media (max-width: 380px) {
  .hero-footnote {
    position: static;
    text-align: left;
    margin-top: 15px;
  }
  .header-nav {
    gap: 12px;
    margin-right: 16px;
  }
  .hero-copy :is(h1, h2) {
    font-size: 3.5rem;
  }
}

/* Theme control and the Scrolling Landscape's green-gray evening palette. */
:root {
  color-scheme: light;
}
.header-nav .theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  width: 36px;
  height: 36px;
  padding: 8px;
  border: 1px solid var(--line);
  border-radius: 50%;
}
.theme-toggle svg {
  width: 18px;
  height: 18px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.theme-toggle .theme-sun {
  display: none;
}
[data-theme='dark'] .theme-toggle .theme-sun {
  display: block;
}
[data-theme='dark'] .theme-toggle .theme-moon {
  display: none;
}
.menu-toggle .menu-label {
  margin: 0;
}

@media screen {
  :root[data-theme='dark'] {
    color-scheme: dark;
    --paper: #293f3d;
    --sage: #3f5951;
    --sage-light: #354e49;
    --ink: #f0f1e7;
    --muted: #cbd6cd;
    --line: #607a6e;
    --accent: #c1d3b4;
    --figure-label: #e0e8db;
    --figure-grid: #91a797;
    --figure-mark: #d2e1c6;
    --face-0: #bccdc0;
    --face-1: #bbcdbf;
    --face-2: #a7bcae;
    --face-3: #b3c6b7;
    --face-4: #c5d3c6;
    --face-5: #d3ded2;
  }
  [data-theme='dark'] button:hover,
  [data-theme='dark'] a:hover {
    color: #ffffff;
  }
  [data-theme='dark'] .landscape {
    background: var(--intro-background);
  }
  [data-theme='dark'] .lesson-nav-link:hover {
    background: #3d5750;
  }
  [data-theme='dark'] .lesson-nav-link[aria-current='location'],
  [data-theme='dark'] .complete-button[aria-pressed='true'] {
    background: #476257;
  }
  [data-theme='dark'] .course-progress progress,
  [data-theme='dark'] .course-progress progress::-webkit-progress-bar {
    background: #435f53;
  }
  [data-theme='dark'] .primary-link,
  [data-theme='dark'] .skip-link {
    background: #d3ded2;
    color: #263e37;
    border-color: #d3ded2;
  }
  [data-theme='dark'] .primary-link:hover {
    background: #edf1e4;
    color: #263e37;
  }
  [data-theme='dark'] .try-note {
    border-color: #b0c5a7;
  }
  [data-theme='dark'] .lesson-figure,
  [data-theme='dark'] .complete-button[aria-pressed='true'],
  [data-theme='dark'] .concept-visual .node,
  [data-theme='dark'] .lab-workspace,
  [data-theme='dark'] .lab-parameters,
  [data-theme='dark'] .lab-volume,
  [data-theme='dark'] .challenge {
    border-color: var(--line);
  }
  [data-theme='dark'] .concept-visual .node {
    background: #405d51;
  }
  [data-theme='dark'] .geometry-lab {
    background: #304b43;
  }
  [data-theme='dark'] .lab-viewport {
    background: #3a554b;
  }
  [data-theme='dark'] .shape-selector button[aria-pressed='true'],
  [data-theme='dark'] .view-selector button[aria-pressed='true'] {
    background: #4b6759;
    border-color: #8fa78e;
  }
  [data-theme='dark'] .challenge-action p.success {
    color: #d5e8b9;
  }
  [data-theme='dark'] dialog input[type='search'],
  [data-theme='dark'] dialog textarea {
    background: #344e46;
  }
}
@media (max-width: 700px) {
  .header-nav {
    gap: 12px;
    margin-right: 16px;
  }
  .header-nav .theme-toggle {
    width: 32px;
    height: 32px;
    padding: 6px;
  }
}
@media (max-width: 420px) {
  .menu-toggle .menu-label {
    display: none;
  }
  .menu-toggle span {
    margin-left: 0;
  }
  .menu-toggle {
    min-width: 24px;
    min-height: 36px;
  }
  .header-nav {
    gap: 10px;
    margin-right: 12px;
  }
}

/* Settings disclosure: the same quiet header styling as Notebook. */
.settings-panel {
  position: absolute;
  top: 100%;
  right: 36px;
  width: 320px;
  display: grid;
  grid-template-rows: 0fr;
  background: var(--paper);
  border: 1px solid var(--line);
  box-shadow: 0 16px 35px #15271924;
  opacity: 0;
  visibility: hidden;
  transition:
    grid-template-rows 0.2s ease,
    opacity 0.2s ease,
    visibility 0.2s;
}
.settings-panel.is-open {
  grid-template-rows: 1fr;
  opacity: 1;
  visibility: visible;
}
.settings-inner {
  min-height: 0;
  overflow: hidden;
}
.settings-content {
  padding: 10px 22px 20px;
}
.setting-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 24px;
  padding: 17px 0;
  border-bottom: 1px solid var(--line);
}
.settings-panel .eyebrow {
  display: block;
  margin: 0;
  font-size: 0.875rem;
  color: var(--muted);
}
.setting-row p {
  font-size: 1.125rem;
  margin-top: 4px;
}
.settings-panel .settings-icon {
  display: inline-flex;
  justify-content: center;
  align-items: center;
  width: 40px;
  height: 40px;
  padding: 10px;
  flex-shrink: 0;
  border: 1px solid var(--line);
  border-radius: 50%;
}
.settings-icon svg {
  width: 18px;
  height: 18px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.settings-panel .settings-note {
  font-size: 0.875rem;
  color: var(--muted);
  line-height: 1.6;
  margin-top: 15px;
}
#settings-toggle[aria-expanded='true'] {
  color: var(--accent);
}
.editable-value {
  cursor: text;
  border-bottom: 1px dotted var(--line);
  border-radius: 0;
}
.editable-value:hover {
  border-color: var(--accent);
}
.editable-value:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}
.dimension-control output {
  white-space: normal;
  overflow-wrap: anywhere;
  text-align: right;
}
.dimension-control .slider-value-editor,
.operation-controls .slider-value-editor {
  width: 90px;
  max-width: 100%;
  height: 28px;
  padding: 3px 5px;
  margin: -5px 0;
  border: 1px solid var(--accent);
  background: var(--paper);
  font: 1rem var(--mono);
  appearance: textfield;
  cursor: text;
}
.slider-value-editor::-webkit-inner-spin-button {
  appearance: none;
}
.dimension-control:has(.slider-value-editor) label {
  flex-wrap: wrap;
}
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}
@media (max-width: 700px) {
  .settings-panel {
    right: 12px;
    width: min(320px, calc(100vw - 24px));
  }
}

/* Readable type, resizing, and reflow. Small screens keep the same text scale. */
html {
  font-size: 100%;
  scroll-padding-top: calc(var(--header) + 1.25rem);
}
body {
  line-height: 1.6;
}
.site-header {
  height: auto;
  min-height: 4.75rem;
  flex-wrap: wrap;
  gap: 0.5rem 1.5rem;
  padding-top: 0.5rem;
  padding-bottom: 0.5rem;
}
.header-nav {
  font-size: 1rem;
  flex-wrap: wrap;
  gap: 1.25rem;
}
.header-nav button,
.menu-toggle {
  font-size: 1rem;
}
.sidebar-top,
.intro-topline,
.intro-bottom,
.figure-topline,
.figure-toolbar,
.lesson-actions,
.figure-result,
.lab-topbar,
.lab-bottom,
.shape-selector,
.view-selector,
.notebook-bottom,
.dimension-control label,
.operation-controls label {
  flex-wrap: wrap;
}
.sidebar {
  max-width: 100vw;
}
.lesson-nav-link {
  min-height: 2.75rem;
}
.lesson p,
.lesson ul,
.lesson ol,
.lesson .try-note,
.hero-description,
.challenge p,
.lab-help,
dialog p {
  font-size: 1.125rem;
  line-height: 1.75;
}
.lesson .lead {
  font-size: 1.25rem;
  line-height: 1.6;
}
.lesson p,
.lesson li,
.lesson td {
  overflow-wrap: anywhere;
}
.lesson,
.geometry-lab,
.lesson-figure {
  scroll-margin-top: calc(var(--header) + 1.25rem);
}
.lesson-figure {
  top: calc(var(--header) + 1rem);
  max-height: calc(100dvh - var(--header) - 2rem);
}
.lesson-figure .figure-topline {
  align-items: flex-start;
}
.hero-copy :is(h1, h2),
.lesson h3,
.lab-heading h2 {
  overflow-wrap: anywhere;
}
.hero-copy,
.hero-figure,
.atlas-grid > *,
.lab-workspace > * {
  min-width: 0;
}
.landscape-sticky {
  overflow: visible;
}
.hero-body {
  height: auto;
  min-height: calc(100% - 9rem);
}
.intro-bottom {
  height: auto;
  min-height: 5rem;
  padding: 1rem 0;
}
.stage-selector {
  flex-wrap: wrap;
  gap: 0.75rem 1.5rem;
}
.scroll-prompt span {
  max-width: none;
}
.figure-result > span:last-child {
  font-size: 0.875rem;
}
.orbit-hint {
  margin-top: 0;
  line-height: 1.6;
}
.dimension-control label,
.dimension-control output {
  font-size: 1rem;
}
.dimension-controls {
  flex-wrap: wrap;
}
.dimension-control {
  flex-basis: 7rem;
}
.concept-visual .node {
  flex-wrap: wrap;
  overflow-wrap: anywhere;
}
.shape-selector button,
.view-selector button,
.text-button,
.complete-button,
.primary-link,
.lesson-next,
.search-trigger,
.about-trigger,
.stage-selector button {
  font-size: 1rem;
  min-height: 2.75rem;
}
.lab-workspace {
  grid-template-columns: minmax(0, 1fr) minmax(14rem, 26%);
}
.lab-parameters .dimension-controls {
  flex-wrap: nowrap;
}
.lab-parameters .dimension-control {
  flex-basis: auto;
}
.challenge-action p,
.figure-note,
.concept-caption,
.settings-panel .settings-note {
  font-size: 1rem;
}
.settings-panel {
  width: 22rem;
  max-width: calc(100vw - 1.5rem);
  max-height: calc(100dvh - var(--header) - 1rem);
  overflow-y: auto;
}
.settings-panel.is-open .settings-inner {
  overflow: visible;
}
.settings-panel .settings-icon {
  width: 2.75rem;
  height: 2.75rem;
}
.setting-row {
  gap: 1rem;
}
.setting-row p {
  font-size: 1rem;
  overflow-wrap: anywhere;
}
.settings-content {
  padding: 0.75rem 1.25rem 1.25rem;
}
.dimension-control .slider-value-editor,
.operation-controls .slider-value-editor {
  font-size: 1rem;
  min-height: 2.25rem;
  height: auto;
  width: 7rem;
  margin: 0;
}
.dialog-heading {
  flex-wrap: wrap;
}
.dialog-heading h2 {
  flex: 1;
}
dialog input[type='search'],
dialog textarea {
  font-size: 1rem;
}
dialog,
.search-results {
  overflow-wrap: anywhere;
}
@media (max-width: 1000px) {
  .sidebar {
    width: min(20rem, 100vw);
  }
  .header-nav {
    margin-right: 0;
  }
}
@media (max-width: 700px) {
  .site-header {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 0 1rem;
    padding: 0.5rem 1rem;
  }
  .brand {
    grid-column: 1;
    grid-row: 1;
  }
  .menu-toggle {
    grid-column: 2;
    grid-row: 1;
    min-height: 2.75rem;
  }
  .header-nav {
    grid-column: 1 / -1;
    grid-row: 2;
    justify-content: space-between;
    margin: 0;
    gap: 0.25rem 0.75rem;
  }
  .header-nav a,
  .header-nav button {
    font-size: 1rem;
    min-height: 2.75rem;
    display: inline-flex;
    align-items: center;
  }
  .header-nav a[href='#space'] {
    display: none;
  }
  .lesson-figure {
    top: auto;
    max-height: none;
    overflow: visible;
  }
  .hero-copy :is(h1, h2) {
    font-size: 3rem;
  }
  .hero-footnote {
    position: static;
    text-align: left;
    margin-top: 1.25rem;
  }
  .intro-topline {
    gap: 1rem;
  }
  .intro-topline > span:first-child {
    max-width: none;
  }
  .hero-figure-caption {
    flex-wrap: wrap;
    font-size: 0.875rem;
  }
  .stage-selector {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .stage-selector button {
    text-align: left;
  }
  .lab-workspace {
    grid-template-columns: minmax(0, 1fr);
  }
  .lab-parameters .dimension-controls {
    flex-direction: column;
  }
  .lab-volume {
    flex-wrap: wrap;
  }
}
/* Tall text must remain readable without being clipped by the sticky introduction. */
@media (max-height: 760px) and (min-width: 701px) {
  .landscape {
    height: auto;
    min-height: 0;
  }
  .landscape-sticky {
    position: relative;
    top: 0;
    height: auto;
    min-height: 0;
    max-height: none;
  }
  .hero-body {
    min-height: 0;
  }
}
.lesson table {
  table-layout: fixed;
}
.lesson th {
  overflow-wrap: anywhere;
}
@media (min-width: 701px) and (min-height: 761px) and (prefers-reduced-motion: no-preference) {
  .landscape {
    height: auto;
    min-height: max(155vh, 1000px);
  }
  .landscape-sticky {
    display: flex;
    flex-direction: column;
    height: auto;
    min-height: calc(100svh - var(--header));
    max-height: none;
  }
  .hero-body {
    flex: 1;
    width: 100%;
    min-height: 0;
  }
}
body {
  overflow-wrap: anywhere;
}
.live-badge {
  white-space: normal;
}
.section-heading > *,
.figure-topline > * {
  min-width: 0;
}
.skip-link {
  top: 0;
  transform: translateY(-150%);
  max-width: calc(100vw - 36px);
}
.skip-link:focus {
  transform: translateY(0);
}
.setting-row {
  flex-wrap: wrap;
}
.setting-row > div {
  flex: 1 1 10rem;
  min-width: 0;
}
@media (max-width: 420px) {
  .settings-content {
    padding: 0.75rem;
  }
}

/* Adjustable contents panel. Its toolbar stays visible while the index scrolls. */
.sidebar {
  display: flex;
  flex-direction: column;
  padding: 0;
  overflow: hidden;
}
.sidebar-top {
  flex-shrink: 0;
  padding: 1rem 1.375rem 0.5rem;
  gap: 0.5rem;
}
.sidebar-top > .eyebrow {
  flex: 1;
}
.sidebar-content {
  flex: 1;
  min-height: 0;
  overflow-y: auto;
  overflow-x: hidden;
  scrollbar-width: thin;
  padding: 0 1.375rem 1.375rem;
}
.sidebar-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
  padding: 0.375rem;
  flex-shrink: 0;
  border: 1px solid var(--line);
  border-radius: 50%;
}
.sidebar-toggle svg {
  width: 1rem;
  height: 1rem;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.sidebar.is-collapsed .sidebar-top {
  padding: 1rem 0;
  justify-content: center;
}
.sidebar.is-collapsed .sidebar-top > :not(.sidebar-toggle) {
  display: none;
}
.sidebar.is-collapsed .sidebar-toggle svg {
  transform: rotate(180deg);
}
.sidebar-resize {
  position: absolute;
  top: 0;
  bottom: 0;
  right: 0;
  width: 8px;
  cursor: col-resize;
  touch-action: none;
}
.sidebar-resize::after {
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  right: 0;
  width: 2px;
  background: transparent;
}
.sidebar-resize:hover::after,
.sidebar-resize:focus-visible::after,
.resizing-sidebar .sidebar-resize::after {
  background: var(--accent);
}
.sidebar-resize:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
}
.resizing-sidebar,
.resizing-sidebar * {
  cursor: col-resize !important;
  user-select: none !important;
}

/* One viewport of context before the interactive introduction. */
:root {
  --intro-background: linear-gradient(155deg, #edf0e7, #dce6d5);
}
[data-theme='dark'] {
  --intro-background: linear-gradient(155deg, #354e4d, #465f54);
}
.course-landing {
  position: relative;
  isolation: isolate;
  display: flex;
  flex-direction: column;
  min-height: calc(100svh - var(--header));
  padding: 30px 48px 0;
  background: var(--intro-background);
  overflow: clip;
  scroll-margin-top: -1.25rem;
}
.course-landing::before {
  content: '';
  position: absolute;
  inset: 0;
  z-index: -1;
  background: inherit;
  filter: blur(24px);
  pointer-events: none;
}
.landing-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  justify-content: center;
  padding: 3rem 0;
  width: 100%;
  max-width: 68rem;
  margin: 0 auto;
}
.landing-description {
  max-width: 62ch;
}
.landing-bottom {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem 2rem;
  border-top: 1px solid var(--line);
  padding: 1.5rem 0;
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--muted);
}
#introduction {
  /* The shared page scroll padding already includes the header height. */
  scroll-margin-top: -1.25rem;
}
@media screen and (prefers-reduced-motion: no-preference) {
  .landing-motion .landing-content {
    filter: blur(var(--landing-blur, 0px));
    opacity: var(--landing-opacity, 1);
  }
  .landing-motion .landscape-sticky {
    filter: blur(var(--reveal-blur, 0px));
    opacity: var(--reveal-opacity, 1);
  }
  .landing-motion .landing-content:focus-within,
  .landing-motion .landscape-sticky:focus-within {
    filter: none;
    opacity: 1;
  }
}
@media (min-width: 1700px) {
  .course-landing {
    padding-left: 75px;
    padding-right: 75px;
  }
}
@media (max-width: 1200px) {
  .course-landing {
    padding-left: 30px;
    padding-right: 30px;
  }
}
@media (max-width: 700px) {
  .course-landing {
    padding: 24px 24px 0;
  }
  .landing-content {
    padding: 2rem 0;
  }
  .landing-content .intro-kicker {
    max-width: 32ch;
  }
}
@media print {
  .course-landing {
    display: none;
  }
}
/* One course page at a time, with independent overflow for long lessons. */
html.paginated {
  scroll-behavior: auto;
  scroll-padding-top: 0;
  --pagination-height: 68px;
}
.paginated .course-pane {
  position: fixed;
  top: var(--header);
  bottom: var(--pagination-height);
  left: var(--sidebar);
  right: 0;
  width: auto;
  height: auto;
  min-height: 0;
  max-height: none;
  margin: 0;
  overflow-y: auto;
  overscroll-behavior: contain;
  scroll-padding: 1rem;
  scroll-margin: 0;
}
.paginated .course-pane:focus {
  outline: none;
}
.paginated #introduction .landscape-sticky {
  position: relative;
  top: 0;
  height: auto;
  min-height: 100%;
  max-height: none;
  display: flex;
  flex-direction: column;
}
.paginated .hero-body {
  flex: 1;
  min-height: 0;
}
.paginated .atlas > .section-heading,
.paginated .subsection-label {
  display: none;
}
.paginated .lesson {
  min-height: 0;
  padding: 0;
  border-bottom: 0;
}
.paginated .figure-column {
  padding: 0;
}
.paginated .lesson-figure {
  position: relative;
  top: 0;
  max-height: none;
  overflow: visible;
}
.paginated #sidebar {
  overscroll-behavior: contain;
}
.course-pagination {
  position: fixed;
  z-index: 19;
  left: var(--sidebar);
  right: 0;
  bottom: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.5rem 1.5rem;
  background: var(--paper);
  border-top: 1px solid var(--line);
}
.course-pagination button {
  min-height: 44px;
  min-width: 0;
  padding: 0.5rem;
  font-size: 1rem;
}
.course-pagination button:disabled {
  opacity: 0.45;
  cursor: default;
}
.course-pagination p {
  min-width: 0;
  margin: 0;
  font-size: 0.875rem;
  text-align: center;
  color: var(--muted);
}
/* Clip moving content to the page viewport; navigation remains stationary. */
.paginated .course-stage {
  position: fixed;
  top: var(--header);
  bottom: var(--pagination-height);
  left: var(--sidebar);
  right: 0;
  overflow: clip;
  isolation: isolate;
}
.paginated .course-stage .course-pane {
  position: absolute;
  inset: 0;
}
.course-stage[data-transitioning] {
  pointer-events: none;
}
@media print {
  .paginated .course-stage {
    position: static;
    overflow: visible;
  }
  .paginated .course-stage .course-pane {
    position: static;
  }
}
@media (max-width: 700px) {
  .course-pagination {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.5fr) minmax(0, 1fr);
    padding: 0.4rem 0.5rem;
    gap: 0.5rem;
  }
}
@media print {
  .course-pagination,
  #course-scroll-track {
    display: none;
  }
  .paginated .course-pane,
  .paginated .lesson[hidden] {
    position: static;
    display: block !important;
    overflow: visible;
  }
}
/* Shared opening-page geometry: copy occupies the same column with or without a figure. */
.course-landing::before {
  content: none;
}
.paginated .course-landing {
  border-bottom: 1px solid var(--line);
}
.paginated :is(#welcome, #introduction) .hero-body {
  width: 100%;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
  gap: 2rem;
}
.paginated :is(#welcome, #introduction) .hero-copy {
  container-type: inline-size;
  display: block;
  width: 100%;
  max-width: none;
  margin: 0;
  padding: 25px 0 20px;
  flex: initial;
}
.paginated :is(#welcome, #introduction) .hero-copy :is(h1, h2) {
  font-size: clamp(2rem, 14cqw, 5.875rem);
}
.paginated :is(#welcome, #introduction) .hero-copy :is(h1, h2) > span,
.paginated :is(#welcome, #introduction) .hero-copy :is(h1, h2) > em {
  white-space: normal;
}
.paginated :is(#welcome, #introduction) .intro-kicker {
  min-height: 2.8em;
  margin: 0;
}
.paginated :is(#welcome, #introduction) .hero-description {
  min-height: 12.25em;
  margin: 0;
}
.paginated :is(#welcome, #introduction) .hero-footnote {
  min-height: 3.4em;
}
.paginated :is(#welcome, #introduction) .intro-bottom {
  min-height: 5rem;
  height: auto;
  flex-shrink: 0;
  padding: 1rem 0;
  margin: 0;
}
@media (max-width: 700px) {
  .paginated :is(#welcome, #introduction) .hero-body {
    grid-template-columns: minmax(0, 1fr);
  }
  .paginated :is(#welcome, #introduction) .hero-copy :is(h1, h2) {
    white-space: normal;
  }
}

.motion-setting {
  flex-wrap: wrap;
}

/* Exercise 04 / Urban metrics and analysis */
.urban-lab {
  --urban-boundary: #293f3d;
}
[data-theme='dark'] .urban-lab {
  --urban-boundary: #f0f1e7;
}
.urban-program-heights {
  border: 0;
  border-top: 1px solid var(--line);
  padding: 1rem 0 0;
  margin: 1.5rem 0;
  min-width: 0;
}
.urban-program-heights legend {
  padding: 0 0.5rem 0 0;
  font-size: 0.9rem;
}
#urban-shade-donut {
  width: 100%;
  max-width: 160px;
}
.urban-guide {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1.5rem;
  list-style: none;
  padding: 0;
  margin: 1.5rem 0 2rem;
}
.urban-guide li {
  border-top: 1px solid var(--line);
  padding-top: 1rem;
  color: var(--muted);
}
.urban-guide strong {
  display: block;
  color: var(--ink);
  margin-bottom: 0.4rem;
  font-weight: 500;
}
.urban-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 1rem;
}
.urban-toolbar [role='group'] {
  display: flex;
  gap: 0.5rem;
}
.urban-lab button:not(.text-button),
.urban-lab select {
  padding: 0.65rem 0.8rem;
  min-height: 44px;
  border: 1px solid var(--line);
  background: transparent;
  color: var(--ink);
  font: inherit;
}
.urban-lab select {
  background: var(--paper);
  width: 100%;
}
.urban-lab button[aria-pressed='true'] {
  background: var(--sage);
  border-color: var(--ink);
}
.urban-workspace {
  grid-template-columns: minmax(0, 1.65fr) minmax(290px, 1fr);
  align-items: start;
}
.urban-workspace .lab-topbar {
  gap: 0.6rem;
  flex-wrap: wrap;
}
.urban-workspace .lab-viewport {
  position: sticky;
  top: 0;
}
.urban-workspace .lab-viewport > .geometry-svg {
  max-height: 560px;
  touch-action: none;
}
.urban-field {
  display: grid;
  gap: 0.45rem;
  margin: 0 0 1rem;
}
.urban-range {
  margin: 1.3rem 0;
}
.urban-range label {
  display: flex;
  justify-content: space-between;
  gap: 0.75rem;
  align-items: baseline;
}
.urban-range output {
  font-family: var(--mono, monospace);
  font-size: 0.875rem;
  text-align: right;
}
.urban-range input {
  width: 100%;
  margin: 0.7rem 0;
  accent-color: var(--accent);
}
.urban-check {
  display: flex;
  gap: 0.6rem;
  align-items: center;
}
.urban-check input {
  width: 18px;
  height: 18px;
  accent-color: var(--accent);
}
.urban-note {
  font-size: 0.875rem;
  color: var(--muted);
  line-height: 1.65;
}
.urban-legend {
  display: flex;
  gap: 1.2rem;
  flex-wrap: wrap;
  font-size: 0.875rem;
}
.urban-legend span {
  display: flex;
  align-items: center;
  gap: 0.45rem;
}
.urban-legend i,
.urban-swatch {
  width: 0.75rem;
  height: 0.75rem;
  display: inline-block;
  border: 1px solid #53675a;
  flex: 0 0 auto;
}
.urban-numbers {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
  padding: 1rem 0;
  border-block: 1px solid var(--line);
}
.urban-numbers span {
  display: block;
  font-size: 0.8rem;
  color: var(--muted);
  margin-bottom: 0.5rem;
}
.urban-numbers strong {
  font-size: clamp(1.1rem, 1.5vw, 1.65rem);
  font-weight: 500;
  overflow-wrap: anywhere;
}
.urban-chart {
  display: grid;
  grid-template-columns: 150px minmax(0, 1fr);
  gap: 1rem;
  align-items: center;
}
#urban-donut {
  width: 100%;
}
.urban-program-row {
  display: grid;
  grid-template-columns: 0.75rem minmax(0, 1fr) auto;
  gap: 0.5rem;
  align-items: center;
  padding: 0.65rem 0;
  border-bottom: 1px solid var(--line);
  font-size: 0.85rem;
}
.urban-program-row strong {
  font-weight: 500;
}
.urban-program-row > :last-child {
  grid-column: 2 / -1;
  color: var(--muted);
}
.urban-comparison {
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line);
}
.urban-comparison p {
  font-size: 0.875rem;
  line-height: 1.65;
}
.urban-hierarchy {
  border-block: 1px solid var(--line);
  margin: 1.5rem 0;
  padding: 1rem 0;
}
.urban-hierarchy summary {
  cursor: pointer;
  padding: 0.65rem 0;
}
#urban-tree details {
  margin-left: 0.65rem;
  padding-left: 0.65rem;
  border-left: 1px solid var(--line);
}
#urban-tree button {
  display: block;
  width: 100%;
  text-align: left;
  margin: 0.4rem 0;
  font-size: 0.8rem;
  overflow-wrap: anywhere;
}
.urban-floor-list {
  max-height: 240px;
  overflow-y: auto;
  overscroll-behavior: contain;
}
#urban-analysis-controls {
  border-top: 1px solid var(--line);
  margin-top: 1.5rem;
}
#urban-inspect-controls {
  margin-top: 1rem;
}
#urban-selection {
  font-size: 1.15rem;
  overflow-wrap: anywhere;
}
#urban-svg [data-urban-pick],
#urban-svg [data-sample-face],
#urban-svg [data-urban-sun] {
  cursor: pointer;
}
@media (max-width: 1100px) {
  .urban-workspace {
    grid-template-columns: minmax(0, 1fr);
  }
  .urban-workspace .lab-viewport {
    position: static;
  }
  .urban-workspace .lab-parameters {
    border-left: 0;
    border-top: 1px solid var(--line);
  }
}
@media (max-width: 700px) {
  .urban-guide {
    grid-template-columns: 1fr;
    gap: 0.75rem;
  }
  .urban-numbers {
    grid-template-columns: 1fr;
  }
  .urban-chart {
    grid-template-columns: minmax(0, 1fr);
  }
  #urban-donut {
    max-width: 150px;
    margin: auto;
  }
  .urban-program-row {
    grid-template-columns: 0.75rem minmax(0, 1fr);
  }
  .urban-program-row strong {
    grid-column: 2;
  }
  .urban-toolbar p {
    margin: 0;
  }
}
.motion-setting select {
  min-width: 0;
  max-width: 100%;
  padding: 0.5rem;
  min-height: 44px;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 4px;
}

/* Vector plan chooser alongside the urban viewer controls. */
.urban-layout-picker {
  margin: 1rem 0;
  padding: 0.8rem;
  border: 1px solid var(--line);
  background: var(--paper);
}
.urban-layout-picker[hidden] {
  display: none;
}
.urban-layout-picker summary {
  cursor: pointer;
}
.urban-layout-cards {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.6rem;
  margin-top: 0.8rem;
}
.urban-layout-cards button {
  color: var(--ink);
  background: transparent;
  padding: 0.5rem;
  border: 1px solid var(--line);
}
.urban-layout-cards button[aria-pressed='true'] {
  outline: 2px solid var(--accent);
}
.urban-layout-cards svg {
  display: block;
  width: 100%;
  height: 120px;
  margin-bottom: 0.4rem;
}
@media (max-width: 600px) {
  .urban-layout-cards {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}
#urban-inspect-controls {
  position: relative;
}
@media (min-width: 1100px) {
  .urban-layout-picker {
    position: absolute;
    right: 0;
    top: 100%;
    width: 210px;
    z-index: 2;
    box-sizing: border-box;
  }
  .urban-layout-cards {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  #urban-inspect-controls:has(.urban-layout-picker:not([hidden])) + #urban-svg {
    width: calc(100% - 225px);
    min-height: 410px;
  }
}
.urban-layout-cards button {
  padding: 0.35rem;
}
.urban-layout-cards button span {
  display: block;
  padding: 0;
  font-size: 12px;
  line-height: 1.35;
  overflow-wrap: normal;
  word-break: normal;
}
.urban-layout-cards svg {
  height: 105px;
}

/* Draw navigation arrows as vectors, independent of platform emoji fonts. */
[class^='ui-arrow-'] {
  display: inline-block;
  width: 1em;
  height: 1em;
  flex: 0 0 1em;
  vertical-align: -0.12em;
  background: currentColor;
  -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath d='M4 12h16m-6-6 6 6-6 6' fill='none' stroke='black' stroke-width='1.6' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E")
    center / contain no-repeat;
  mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath d='M4 12h16m-6-6 6 6-6 6' fill='none' stroke='black' stroke-width='1.6' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E")
    center / contain no-repeat;
}
.ui-arrow-left {
  transform: rotate(180deg);
}
.ui-arrow-up {
  transform: rotate(-90deg);
}
.ui-arrow-down {
  transform: rotate(90deg);
}
.ui-arrow-up-right {
  transform: rotate(-45deg);
}