:root {
  color-scheme: light;
  --paper: #f4f5f2;
  --panel: #fff;
  --ink: #20352f;
  --muted: #687771;
  --line: #dce3dd;
  --accent: #167565;
  --soft: #e6f1eb;
  --orange: #d87942;
  --shadow: 0 12px 35px #19392c08;
  font-family:
    Inter,
    ui-sans-serif,
    -apple-system,
    BlinkMacSystemFont,
    "Segoe UI",
    sans-serif;
  font-synthesis: none;
}
* {
  box-sizing: border-box;
}
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-size: 0.875rem;
  line-height: 1.6;
}
button,
input,
select {
  font: inherit;
}
button,
a,
input,
select {
  -webkit-tap-highlight-color: transparent;
}
button {
  cursor: pointer;
}
button:disabled {
  opacity: 0.5;
  cursor: wait;
}
a {
  color: var(--accent);
  text-underline-offset: 4px;
}
button:focus-visible,
a:focus-visible,
input:focus-visible,
select:focus-visible,
summary:focus-visible {
  outline: 3px solid #d87942;
  outline-offset: 4px;
}
button {
  color: inherit;
}
button,
input,
select {
  border-radius: 7px;
}
button {
  border: 1px solid var(--line);
  background: var(--panel);
  padding: 8px 12px;
  font-weight: 600;
  transition:
    background 0.18s,
    border-color 0.18s,
    transform 0.18s;
}
button:hover {
  border-color: #91afa3;
  background: var(--soft);
}
button:active {
  transform: translateY(1px);
}
button.primary {
  background: var(--accent);
  color: white;
  border-color: var(--accent);
}
button.primary:hover {
  background: #105f52;
}
h1,
h2,
h3,
p {
  margin-top: 0;
}
h1,
h2,
h3 {
  line-height: 1.2;
  font-weight: 650;
  letter-spacing: -0.04em;
}
h1 {
  font-size: clamp(26px, 3vw, 43px);
  margin-bottom: 9px;
}
h2 {
  font-size: 1.5rem;
}
h3 {
  font-size: 1.0625rem;
  letter-spacing: -0.025em;
}
.skip {
  position: absolute;
  left: 12px;
  top: -60px;
  z-index: 10;
  background: white;
  padding: 10px;
}
.skip:focus {
  top: 10px;
}
.topbar {
  height: 73px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 32px;
  border-bottom: 1px solid var(--line);
  background: var(--panel);
  gap: 20px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 13px;
  text-decoration: none;
  color: var(--ink);
  font-size: 1.125rem;
  font-weight: 700;
  letter-spacing: -0.04em;
}
.brand-mark {
  display: grid;
  place-items: center;
  width: 35px;
  height: 35px;
  background: var(--ink);
  color: #a8e3c8;
  border-radius: 9px;
  font-size: 1.5rem;
}
.brand small {
  font-size: 0.875rem;
  display: block;
  letter-spacing: 0.13em;
  color: var(--muted);
  font-weight: 600;
  line-height: 1.2;
}
.top-links {
  display: flex;
  align-items: center;
  gap: 24px;
  font-size: 0.875rem;
}
.top-links a {
  text-decoration: none;
  color: var(--muted);
}
.lab-status {
  display: flex;
  align-items: center;
  gap: 7px;
  font-size: 0.875rem;
  color: var(--muted);
}
.dot {
  height: 6px;
  width: 6px;
  border-radius: 50%;
  background: #39aa7e;
  display: inline-block;
}
.workspace {
  max-width: 1800px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 228px minmax(0, 1fr);
  min-height: calc(100vh - 73px);
}
.journey {
  padding: 28px 16px 24px 24px;
  border-right: 1px solid var(--line);
  background: #f8f9f6;
}
.eyebrow {
  text-transform: uppercase;
  font-size: 0.875rem;
  letter-spacing: 0.16em;
  font-weight: 750;
  color: var(--muted);
}
.journey-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 8px 14px;
}
.journey-head span:last-child {
  font-size: 0.875rem;
  color: var(--accent);
  background: var(--soft);
  padding: 3px 7px;
  border-radius: 5px;
}
.module-list {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.module-button {
  display: flex;
  text-align: left;
  gap: 10px;
  align-items: center;
  padding: 10px 9px;
  border: 1px solid transparent;
  background: transparent;
  font-size: 0.875rem;
  font-weight: 500;
  width: 100%;
  line-height: 1.3;
}
.module-button .num {
  font:
    0.875rem ui-monospace,
    monospace;
  color: #9aa59d;
  min-width: 20px;
}
.module-button.active {
  background: var(--panel);
  border-color: var(--line);
  box-shadow: 0 3px 10px #1c3c2b05;
  color: var(--accent);
  font-weight: 700;
}
.module-button.active .num {
  color: var(--accent);
}
.module-button.completed .num {
  color: var(--accent);
}
.journey-footer {
  margin: 24px 8px 0;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  font-size: 0.875rem;
  color: var(--muted);
}
.progress-track {
  height: 4px;
  background: var(--line);
  border-radius: 3px;
  margin: 10px 0;
}
.progress-track span {
  display: block;
  height: 100%;
  background: var(--accent);
  border-radius: 3px;
  transition: width 0.4s;
}
.journey-footer a {
  display: block;
  margin-top: 12px;
}
.main {
  min-width: 0;
  padding: 30px 30px 50px;
}
.heading {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 20px;
  margin-bottom: 24px;
}
.heading .eyebrow {
  color: var(--accent);
  margin-bottom: 11px;
}
.heading p {
  color: var(--muted);
  max-width: 660px;
  font-size: 0.875rem;
  margin: 0;
}
.lesson-count {
  white-space: nowrap;
  color: var(--muted);
  font:
    0.875rem ui-monospace,
    monospace;
  padding-bottom: 4px;
}
.experiment {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 258px;
  gap: 0;
  border: 1px solid var(--line);
  border-radius: 13px;
  overflow: hidden;
  background: var(--panel);
  box-shadow: var(--shadow);
}
.visual-column {
  min-width: 0;
  background: #0b1423;
  color: #dbe7f2;
  position: relative;
}
.stage-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  padding: 18px 21px 0;
  position: absolute;
  top: 0;
  width: 100%;
  z-index: 2;
  pointer-events: none;
}
.stage-name {
  font-size: 0.875rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: #bacbd5;
}
.live-pill {
  border: 1px solid #4e786c66;
  background: #213d353d;
  padding: 3px 8px;
  border-radius: 4px;
  font:
    0.875rem ui-monospace,
    monospace;
  color: #91dcc1;
}
.stage {
  height: 408px;
  min-height: 320px;
  position: relative;
}
.stage canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
  touch-action: none;
  cursor: grab;
}
.stage canvas:active {
  cursor: grabbing;
}
.webgl-fallback {
  padding: 100px 40px;
  color: #c4d5df;
}
.stage-caption {
  position: absolute;
  left: 20px;
  right: 20px;
  bottom: 107px;
  display: flex;
  justify-content: space-between;
  align-items: end;
  gap: 12px;
  pointer-events: none;
  font:
    0.875rem ui-monospace,
    monospace;
  color: #8aa0b4;
}
.legend {
  width: 160px;
}
.legend-gradient {
  height: 5px;
  border-radius: 4px;
  margin: 5px 0;
  background: linear-gradient(
    90deg,
    #262b70,
    #335fbd,
    #189cab,
    #72d4ae,
    #eddf78,
    #f6a45e,
    #ec6265
  );
}
.legend-values {
  display: flex;
  justify-content: space-between;
  font-size: 0.875rem;
  color: #b2c5d2;
}
.stage-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 11px 17px;
  background: #111e2d;
  border-top: 1px solid #253445;
}
.stage-toolbar button {
  border-color: #314256;
  background: #182839;
  color: #c1d2df;
  font-size: 0.875rem;
  padding: 5px 9px;
  font-weight: 500;
}
.stage-toolbar button:hover {
  background: #253c50;
}
.stage-toolbar .tool-group {
  display: flex;
  gap: 5px;
}
.camera-hint {
  font-size: 0.875rem;
  color: #8a9fb1;
}
.metrics {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-top: 1px solid #253445;
  background: #0e1a29;
}
.metric {
  padding: 13px 17px;
  border-right: 1px solid #253445;
  min-width: 0;
}
.metric:last-child {
  border: 0;
}
.metric-label {
  font-size: 0.875rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #8ba1b6;
}
.metric-value {
  font:
    500 20px ui-monospace,
    "Cascadia Code",
    monospace;
  letter-spacing: -0.05em;
  color: #dbebf4;
  margin-top: 3px;
  white-space: nowrap;
}
.metric-value small {
  font-size: 0.875rem;
  letter-spacing: 0;
  color: #91acbc;
  margin-left: 4px;
}
.inspector {
  padding: 20px 20px 15px;
  max-height: 560px;
  overflow: auto;
}
.inspector-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 19px;
}
.inspector-head h2 {
  font-size: 0.875rem;
  margin: 0;
  letter-spacing: -0.01em;
}
.inspector-head button {
  border: 0;
  padding: 0;
  background: none;
  font-size: 0.875rem;
  color: var(--muted);
  font-weight: 500;
}
.control {
  margin-bottom: 18px;
}
.control label,
.control .control-label {
  font-size: 0.875rem;
  font-weight: 650;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 7px;
}
.control output {
  font:
    0.875rem ui-monospace,
    monospace;
  color: var(--accent);
}
.control select {
  width: 100%;
  padding: 7px 9px;
  border: 1px solid var(--line);
  color: var(--ink);
  background: var(--paper);
  font-size: 0.875rem;
}
.control input[type="range"] {
  width: 100%;
  height: 4px;
  accent-color: var(--accent);
  cursor: pointer;
  margin: 8px 0;
  display: block;
}
.range-ends {
  display: flex;
  justify-content: space-between;
  color: #88958c;
  font-size: 0.875rem;
}
.control small {
  font-size: 0.875rem;
  line-height: 1.5;
  color: var(--muted);
  display: block;
  margin-top: 6px;
}
.control.check label {
  justify-content: flex-start;
  font-weight: 500;
  gap: 8px;
}
.control.check {
  margin-bottom: 10px;
}
.control input[type="checkbox"] {
  accent-color: var(--accent);
}
.inspector .primary {
  width: 100%;
  font-size: 0.875rem;
}
.inspector-note {
  border-top: 1px solid var(--line);
  padding-top: 12px;
  margin: 15px 0 0;
  color: var(--muted);
  font-size: 0.875rem;
  line-height: 1.6;
}
.result-status {
  font-size: 0.875rem;
  color: var(--accent);
  min-height: 18px;
  margin: 8px 0;
}
.below {
  display: grid;
  grid-template-columns: minmax(0, 1.18fr) minmax(0, 1fr);
  gap: 20px;
  margin-top: 20px;
}
.card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 11px;
  padding: 23px;
  box-shadow: var(--shadow);
  min-width: 0;
}
.card .eyebrow {
  margin-bottom: 10px;
  color: var(--accent);
}
.card h2 {
  font-size: 1.25rem;
  margin-bottom: 13px;
}
.card p {
  font-size: 0.875rem;
  line-height: 1.85;
  color: var(--muted);
  margin-bottom: 12px;
}
.equation {
  font:
    0.875rem ui-monospace,
    monospace;
  padding: 13px 16px;
  background: var(--paper);
  border-left: 3px solid #87b5a0;
  border-radius: 0 6px 6px 0;
  margin: 17px 0;
  color: var(--ink);
  overflow: auto;
}
.takeaway {
  padding: 12px 14px;
  border: 1px solid #d4e5d9;
  background: #f4f9f5;
  border-radius: 7px;
  margin: 14px 0 0;
}
.takeaway p {
  margin: 0;
  font-size: 0.875rem;
}
.takeaway strong {
  color: var(--accent);
}
.chart-heading {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 8px;
}
.chart-heading h2 {
  font-size: 0.9375rem;
  margin: 0;
}
.chart-heading small {
  color: var(--muted);
  font-size: 0.875rem;
}
.chart {
  width: 100%;
  height: 176px;
  display: block;
  margin-top: 13px;
  overflow: visible;
}
.chart text {
  font-family: ui-monospace, monospace;
  font-size: 0.875rem;
  fill: #7b8c83;
}
.chart .gridline {
  stroke: #e5eae5;
  stroke-width: 1;
}
.chart-caption {
  font-size: 0.875rem !important;
  margin: 4px 0 0 !important;
  line-height: 1.6 !important;
}
.probe {
  margin-top: 16px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
  font:
    0.875rem ui-monospace,
    monospace;
  color: var(--muted);
  line-height: 1.7;
}
.probe strong {
  color: var(--ink);
}
.probe-row {
  display: flex;
  gap: 8px;
  align-items: center;
  justify-content: space-between;
}
.probe select {
  font-size: 0.875rem;
  padding: 3px;
  border: 1px solid var(--line);
  background: var(--paper);
  max-width: 125px;
}
.challenge {
  grid-column: 1/-1;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 22px;
  background: #edf3ed;
  border-color: #d3e0d4;
}
.challenge .eyebrow {
  color: var(--accent);
}
.challenge h2 {
  font-size: 1.125rem;
  margin-bottom: 8px;
}
.challenge p {
  margin: 0;
}
.answers {
  display: flex;
  flex-direction: column;
  gap: 7px;
}
.answers button {
  text-align: left;
  font-size: 0.875rem;
  font-weight: 500;
  padding: 9px 12px;
  background: #ffffffbf;
}
.answers button.correct {
  background: #d5ecdd;
  border-color: #80b594;
}
.answers button.incorrect {
  background: #fff1e9;
  border-color: #d99871;
}
.feedback {
  font-size: 0.875rem;
  margin-top: 9px;
  color: var(--ink);
  min-height: 18px;
}
.lesson-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 24px;
  gap: 14px;
}
.lesson-bottom small {
  font-size: 0.875rem;
  color: var(--muted);
}
.lesson-bottom button {
  font-size: 0.875rem;
}
.details {
  margin-top: 20px;
  border-top: 1px solid var(--line);
  padding-top: 15px;
  font-size: 0.875rem;
  color: var(--muted);
}
.details summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--ink);
}
.details p {
  margin: 10px 0;
}
.details ul {
  padding-left: 17px;
}
.details code {
  font:
    0.875rem ui-monospace,
    monospace;
}
.phase-strip {
  display: flex;
  gap: 5px;
  margin: 10px 0 15px;
}
.phase-strip span {
  flex: 1;
  font-size: 0.875rem;
  text-transform: uppercase;
  background: var(--paper);
  padding: 5px 2px;
  text-align: center;
  border-radius: 3px;
}
.phase-strip span.current {
  background: var(--soft);
  color: var(--accent);
  font-weight: 700;
}
.terminal {
  background: #122331;
  color: #a6d9c7;
  border-radius: 7px;
  padding: 13px;
  font:
    0.875rem/1.8 ui-monospace,
    monospace;
  white-space: pre-wrap;
  overflow: auto;
  max-height: 140px;
  margin: 10px 0;
}
.matrix {
  display: grid;
  gap: 2px;
  grid-template-columns: repeat(12, 1fr);
  max-width: 210px;
  margin: 18px auto;
}
.matrix span {
  aspect-ratio: 1;
  border-radius: 2px;
}
.matrix-key {
  display: flex;
  gap: 12px;
  justify-content: center;
  font-size: 0.875rem;
  color: var(--muted);
}
.toast {
  position: fixed;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--ink);
  color: white;
  padding: 10px 20px;
  border-radius: 8px;
  box-shadow: 0 5px 25px #0002;
  font-size: 0.875rem;
  z-index: 50;
}
.mobile-nav {
  display: none;
}
.chart-legend {
  display: flex;
  gap: 14px;
  font-size: 0.875rem;
  color: var(--muted);
  margin-top: 3px;
}
.chart-legend i {
  display: inline-block;
  width: 14px;
  height: 2px;
  background: var(--accent);
  vertical-align: middle;
  margin-right: 5px;
}
.chart-legend i.orange {
  background: var(--orange);
}
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}
@media (min-width: 1550px) {
  .stage {
    height: 480px;
  }
  .inspector {
    max-height: 632px;
  }
  .main {
    padding: 34px 40px;
  }
  .workspace {
    grid-template-columns: 240px minmax(0, 1fr);
  }
}
@media (max-width: 1180px) {
  .workspace {
    grid-template-columns: 190px minmax(0, 1fr);
  }
  .journey {
    padding: 23px 10px;
  }
  .main {
    padding: 24px 20px;
  }
  .experiment {
    grid-template-columns: minmax(0, 1fr) 225px;
  }
  .inspector {
    padding: 17px 15px;
  }
  .stage {
    height: 380px;
  }
  .camera-hint {
    display: none;
  }
  .metric {
    padding: 12px;
  }
  .metric-value {
    font-size: 1.125rem;
  }
  .below {
    gap: 14px;
  }
  .card {
    padding: 19px;
  }
}
@media (max-width: 960px) {
  .workspace {
    grid-template-columns: 1fr;
  }
  .journey {
    display: none;
  }
  .main {
    padding: 20px;
  }
  .mobile-nav {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 22px;
  }
  .mobile-nav label {
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--muted);
  }
  .mobile-nav select {
    padding: 9px;
    border: 1px solid var(--line);
    background: var(--panel);
    flex: 1;
    min-width: 0;
  }
  .heading {
    margin-bottom: 19px;
  }
  .stage {
    height: 410px;
  }
  .experiment {
    grid-template-columns: minmax(0, 1fr) 245px;
  }
  .topbar {
    padding: 0 22px;
  }
  .top-links {
    gap: 17px;
  }
}
@media (max-width: 650px) {
  .topbar {
    height: 63px;
    padding: 0 16px;
  }
  .brand {
    font-size: 1rem;
  }
  .top-links a:not(:first-child),
  .lab-status {
    display: none;
  }
  .top-links {
    font-size: 0.875rem;
  }
  .main {
    padding: 19px 12px 35px;
  }
  .heading {
    align-items: start;
    gap: 8px;
    padding: 0 4px;
  }
  .heading p {
    font-size: 0.875rem;
  }
  .lesson-count {
    display: none;
  }
  h1 {
    font-size: 1.8125rem;
  }
  .experiment {
    grid-template-columns: 1fr;
  }
  .stage {
    height: 330px;
    min-height: 0;
  }
  .stage-top {
    padding: 14px 15px;
  }
  .stage-caption {
    left: 14px;
    right: 14px;
    bottom: 105px;
  }
  .stage-caption .scene-note {
    max-width: 125px;
    text-align: right;
    font-size: 0.875rem;
  }
  .stage-toolbar {
    padding: 10px;
  }
  .stage-toolbar button {
    padding: 5px 7px;
    font-size: 0.875rem;
  }
  .metric {
    padding: 12px 10px;
  }
  .metric-value {
    font-size: 1.0625rem;
  }
  .metric-label {
    font-size: 0.875rem;
  }
  .inspector {
    max-height: none;
    padding: 18px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0 20px;
  }
  .inspector-head,
  .inspector-note,
  .result-status,
  .inspector > .primary,
  .inspector > .phase-strip,
  .inspector > .terminal {
    grid-column: 1/-1;
  }
  .control {
    margin-bottom: 18px;
  }
  .control label {
    font-size: 0.875rem;
  }
  .below {
    grid-template-columns: 1fr;
    gap: 13px;
    margin-top: 13px;
  }
  .challenge {
    grid-column: auto;
    grid-template-columns: 1fr;
    gap: 15px;
  }
  .card {
    padding: 19px;
  }
  .chart {
    height: 175px;
  }
  .lesson-bottom {
    align-items: flex-start;
  }
  .lesson-bottom small {
    max-width: 165px;
  }
  .mobile-nav {
    margin-bottom: 16px;
  }
  .legend {
    width: 130px;
  }
}
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition: none !important;
    animation: none !important;
  }
}
.visual-column {
  display: flex;
  flex-direction: column;
}
.stage {
  flex: 1;
}
.stage-caption {
  bottom: 16px;
  z-index: 1;
}
.stage-toolbar,
.metrics {
  flex-shrink: 0;
}
.stage-caption .scene-note {
  text-align: right;
  max-width: 235px;
}
.journey-head > span:first-child {
  font-size: 0.875rem;
}
.journey-head > span:last-child {
  white-space: nowrap;
}
@media (max-width: 650px) {
  .stage-caption {
    bottom: 15px;
  }
  .stage {
    flex: none;
  }
  .stage-caption .scene-note {
    max-width: 130px;
  }
}