.demo-page main {
  display: block;
  width: min(100%, var(--content-width));
  margin-inline: auto;
  padding-inline: var(--page-gutter);
}

.demo-page .demo-section {
  grid-column: auto;
  grid-row: auto;
  min-height: 0;
  margin-block: 1.5rem 3rem;
  padding: clamp(2rem, 4vw, 4rem);
}

.demo-page .demo-heading .section-index,
.demo-page .demo-heading > p:last-child {
  display: block;
}

.demo-page .demo-heading .section-index {
  margin: 0 0 1rem;
  color: var(--lime);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.demo-page .demo-heading h1 {
  max-width: none;
  margin: 0;
  font-size: clamp(3rem, 5vw, 5rem);
  font-weight: 520;
  letter-spacing: -0.05em;
  line-height: 0.96;
}

.demo-page .demo-heading > p:last-child {
  max-width: 48rem;
  margin: 1.25rem 0 0;
  color: #b7c0d1;
  font-size: 1rem;
  line-height: 1.55;
}

.learning-lab {
  margin-top: 2rem;
  overflow: clip;
  border: 1px solid #36405a;
  background: #0d1424;
  color: var(--paper);
}

.lab-topbar {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto auto;
  gap: 1rem;
  align-items: center;
  min-height: 4.25rem;
  padding: 0.75rem 1rem;
  border-bottom: 1px solid #36405a;
  background: #11192b;
}

.lab-topbar > div {
  display: flex;
  min-width: 0;
  gap: 0.55rem;
  align-items: baseline;
}

.lab-topbar span,
.context-label,
.choice-set legend {
  color: #aeb7ca;
  font-size: 0.72rem;
  font-weight: 650;
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

.lab-topbar code {
  min-width: 0;
  overflow: hidden;
  color: var(--lime);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.lab-topbar p {
  margin: 0;
  color: #c8cfdd;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  white-space: nowrap;
}

.learning-lab button {
  min-height: 2.75rem;
  border: 1px solid #52607b;
  border-radius: var(--radius-small);
  background: transparent;
  color: var(--paper);
  cursor: pointer;
  font-weight: 600;
  transition: transform 100ms var(--ease-out);
}

.learning-lab button:hover,
.learning-lab button:focus-visible {
  border-color: var(--lime);
}

.learning-lab .button-demo {
  min-height: 3.25rem;
  margin-top: 1.5rem;
  padding: 0.8rem 1.15rem;
  border-color: var(--cobalt);
  background: var(--cobalt);
  color: var(--paper);
}

.learning-lab .button-demo:hover,
.learning-lab .button-demo:focus-visible {
  border-color: var(--lime);
  background: var(--lime);
  color: var(--ink);
}

.lab-topbar .enhanced-control {
  min-height: 2.75rem;
  padding: 0.55rem 0.85rem;
  color: #c8cfdd;
  font-size: 0.78rem;
}

.lab-workspace {
  display: grid;
  grid-template-columns: minmax(9rem, 0.55fr) minmax(18rem, 1.45fr) minmax(
      15rem,
      0.8fr
    );
  min-height: 36rem;
}

.lab-route {
  position: relative;
  display: grid;
  align-content: center;
  gap: 0;
  min-width: 0;
  margin: 0;
  padding: 1.25rem 1rem;
  border-right: 1px solid #36405a;
  background: #11192b;
  list-style: none;
}

.lab-route li {
  position: relative;
  display: grid;
  grid-template-columns: 2rem minmax(0, 1fr);
  gap: 0.65rem;
  align-items: center;
  min-height: 5rem;
  color: #7f899e;
  font-size: 0.78rem;
  font-weight: 600;
  line-height: 1.25;
}

.lab-route li::before {
  position: absolute;
  top: 3.5rem;
  bottom: -1.5rem;
  left: 0.94rem;
  width: 1px;
  background: #46516b;
  content: '';
}

.lab-route li:last-child::before {
  content: none;
}

.lab-route li > span {
  position: relative;
  z-index: 1;
  display: grid;
  place-items: center;
  width: 2rem;
  height: 2rem;
  border: 1px solid #52607b;
  border-radius: 50%;
  background: #11192b;
  color: #9ca6ba;
  font-family: var(--font-mono);
  font-size: 0.68rem;
}

.lab-route li[data-state='active'] {
  color: var(--paper);
}

.lab-route li[data-state='active'] > span {
  border-color: var(--lime);
  box-shadow: 0 0 0 4px rgb(199 243 74 / 13%);
  background: var(--lime);
  color: var(--ink);
}

.lab-route li[data-state='complete'] {
  color: #dce3ef;
}

.lab-route li[data-state='complete'] > span {
  border-color: var(--cobalt);
  background: var(--cobalt);
  color: var(--paper);
}

.lab-route li[data-state='bridge'] > span,
.lab-route li[data-state='draft'] > span {
  border-style: dashed;
  border-color: var(--coral);
  color: var(--coral);
}

.lab-route li[data-state='bridge'],
.lab-route li[data-state='draft'] {
  color: #ffd0c9;
}

.lab-center {
  display: grid;
  grid-template-rows: minmax(13rem, 0.8fr) minmax(21rem, 1.2fr);
  min-width: 0;
  background: var(--midnight);
}

.membrane-figure {
  display: grid;
  grid-template-rows: minmax(10.5rem, 1fr) auto;
  min-width: 0;
  margin: 0;
  border-bottom: 1px solid #36405a;
  background: #0e1628;
}

.membrane-scene {
  position: relative;
  min-height: 10.5rem;
  overflow: hidden;
  container-type: inline-size;
}

.membrane-scene::before,
.membrane-scene::after {
  position: absolute;
  top: 1.2rem;
  bottom: 1.2rem;
  left: calc(50% - 0.45rem);
  width: 0.9rem;
  background: repeating-radial-gradient(
    circle at 50% 0.4rem,
    #6f7c9c 0 0.22rem,
    transparent 0.24rem 0.78rem
  );
  content: '';
}

.membrane-scene::after {
  left: calc(50% + 0.55rem);
}

.membrane-layer {
  position: absolute;
  top: 0;
  bottom: 0;
  left: calc(50% - 0.8rem);
  width: 2.6rem;
  border-inline: 1px solid rgb(174 183 202 / 20%);
  background: rgb(82 96 123 / 10%);
}

.transport-channel {
  position: absolute;
  z-index: 2;
  top: 50%;
  left: calc(50% - 1.15rem);
  width: 3.3rem;
  height: 3.6rem;
  transform: translateY(-50%);
  border: 1px solid var(--coral);
  border-block-width: 0.45rem;
  background: #172038;
}

.molecule {
  position: absolute;
  z-index: 3;
  display: grid;
  place-items: center;
  min-width: 2.6rem;
  min-height: 2.6rem;
  padding: 0.3rem;
  border: 1px solid currentColor;
  border-radius: 50%;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 700;
  transition:
    transform 280ms var(--ease-out),
    opacity 180ms var(--ease-out);
}

.molecule-oxygen {
  top: 18%;
  left: 8%;
  color: var(--lime);
}

.molecule-glucose {
  bottom: 15%;
  left: 12%;
  min-width: 4.1rem;
  border-radius: 999px;
  color: #ffbcb2;
}

.molecule-sodium {
  top: 48%;
  left: 24%;
  color: #93adff;
}

.membrane-figure[data-result='oxygen'] .molecule-oxygen {
  transform: translateX(clamp(7rem, 12vw, 10rem));
}

.membrane-figure[data-result='oxygen'] .molecule-glucose {
  transform: translateX(clamp(2.25rem, 5vw, 4.5rem));
}

.membrane-figure[data-result='oxygen'] .molecule-sodium {
  transform: translateX(clamp(1.5rem, 3vw, 2.75rem));
}

.membrane-figure figcaption {
  margin: 0;
  padding: 0.7rem 1rem;
  border-top: 1px solid #2a3550;
  color: #9ea8bc;
  font-size: 0.72rem;
  line-height: 1.4;
}

.lab-activity {
  position: relative;
  min-width: 0;
  min-height: 21rem;
  overflow: hidden;
}

.lab-activity > section {
  min-height: 21rem;
  padding: clamp(1.4rem, 2.5vw, 2rem);
  animation: demo-panel-enter 240ms var(--ease-out) both;
}

.lab-activity .demo-step {
  margin: 0 0 0.7rem;
  color: var(--lime);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.lab-activity h2,
.lab-context h2 {
  margin: 0;
  color: var(--paper);
  font-weight: 570;
  letter-spacing: -0.035em;
  line-height: 1.08;
}

.lab-activity h2 {
  max-width: 18ch;
  font-size: clamp(1.55rem, 2.3vw, 2.15rem);
}

.lab-activity section > p:not(.demo-step) {
  max-width: 34rem;
  margin: 1rem 0 0;
  color: #b7c0d1;
  line-height: 1.5;
}

.choice-set {
  display: grid;
  min-width: 0;
  margin: 1.25rem 0 0;
  padding: 0;
  border: 0;
}

.choice-set legend {
  margin-bottom: 0.5rem;
}

.molecule-choices {
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-block: 1px solid #36405a;
}

.choice-set label {
  position: relative;
  cursor: pointer;
}

.molecule-choices label + label {
  border-left: 1px solid #36405a;
}

.choice-set input {
  position: absolute;
  z-index: 2;
  inset: 0;
  width: 100%;
  height: 100%;
  margin: 0;
  opacity: 0;
  cursor: pointer;
}

.choice-set label > span {
  display: flex;
  min-height: 3.5rem;
  padding: 0.65rem;
  align-items: center;
  justify-content: center;
  color: #c8cfdd;
  font-size: 0.83rem;
  font-weight: 600;
  pointer-events: none;
  text-align: center;
}

.choice-set label > span small {
  display: none;
}

.choice-set input:checked + span {
  background: var(--lime);
  color: var(--ink);
}

.choice-set input:focus-visible + span {
  outline: 3px solid var(--focus-dark);
  outline-offset: -3px;
}

.confidence-choices {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.5rem;
  margin-top: 1rem;
}

.confidence-choices label > span {
  min-height: 2.75rem;
  border: 1px solid #52607b;
  justify-content: flex-start;
}

.form-error {
  margin: 0.85rem 0 0;
  padding: 0.65rem 0.8rem;
  border-left: 3px solid var(--coral);
  background: #1a2134;
  color: #ffd0c9;
  font-size: 0.82rem;
  font-weight: 600;
}

.choice-set[aria-invalid='true'] {
  outline: 2px solid var(--coral);
  outline-offset: 3px;
}

.demo-actions {
  gap: 0.65rem;
  margin-top: 1.5rem;
}

.demo-actions button,
.lab-activity [data-demo-action='back'] {
  padding: 0.65rem 1rem;
}

.demo-actions .button-demo {
  margin-top: 0;
}

.answer-grid {
  grid-template-columns: 1fr;
  gap: 0.55rem;
  margin-top: 1.5rem;
}

.answer-grid button {
  min-height: 3.25rem;
  padding: 0.7rem 0.9rem;
  text-align: left;
}

.answer-grid button[data-state='incorrect'] {
  border-color: var(--coral);
  color: #ffd0c9;
}

.answer-grid button[data-state='correct'] {
  border-color: var(--lime);
  background: var(--lime);
  color: var(--ink);
}

.feedback {
  margin-top: 1rem;
  padding: 0.8rem 1rem;
  border-left: 3px solid var(--coral);
  background: #1a2134;
  color: #dce3ef;
  font-size: 0.85rem;
}

.lab-context {
  min-width: 0;
  padding: 1.25rem 1rem;
  overflow: hidden;
  border-left: 1px solid #36405a;
  background: #0f1728;
}

.lab-context > .context-label:first-child {
  margin-top: 0;
}

.context-label {
  margin: 1.25rem 0 0.5rem;
}

[data-evidence-context] {
  min-height: 5.25rem;
  padding-block: 0.8rem;
  border-block: 1px solid #36405a;
  color: #d1d8e5;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  line-height: 1.55;
}

[data-evidence-context] p {
  margin: 0;
}

.lab-context h2 {
  font-size: 1.25rem;
}

.pack-tabs {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin-top: 1rem;
}

.pack-tabs button {
  min-width: 0;
  min-height: 2.75rem;
  padding: 0.55rem 0.35rem;
  border-color: #36405a;
  border-radius: 0;
  color: #9ea8bc;
  font-family: var(--font-mono);
  font-size: 0.62rem;
}

.pack-tabs button[aria-selected='true'] {
  border-color: var(--lime);
  background: var(--lime);
  color: var(--ink);
}

[data-pack-inspector] pre {
  max-height: 16rem;
  margin: 0;
  padding: 0.9rem;
  overflow: auto;
  border: 1px solid #36405a;
  border-top: 0;
  background: #090f1c;
  color: #b9df72;
  font-family: var(--font-mono);
  font-size: 0.62rem;
  line-height: 1.5;
  tab-size: 2;
}

.draft-toggle {
  display: grid;
  grid-template-columns: 1.15rem minmax(0, 1fr);
  gap: 0.65rem;
  align-items: start;
  min-height: 2.75rem;
  margin-top: 0.9rem;
  cursor: pointer;
  color: #dce3ef;
  font-size: 0.78rem;
  font-weight: 600;
  line-height: 1.35;
}

.draft-toggle input {
  width: 1.15rem;
  height: 1.15rem;
  margin: 0.1rem 0 0;
  accent-color: var(--lime);
}

[data-draft-status] {
  margin: 0.4rem 0 0;
  color: #9ea8bc;
  font-family: var(--font-mono);
  font-size: 0.68rem;
}

.static-demo {
  margin: 1.25rem 0 0;
  padding: 0.75rem 0;
  border-block: 1px solid #52607b;
  color: #dce3ef;
}

.static-demo summary {
  cursor: pointer;
  font-weight: 650;
}

.static-demo p,
.static-demo ol {
  color: #b7c0d1;
}

html:not(.js) .learning-lab {
  display: none;
}

html:not(.js) .static-demo summary {
  display: flex;
  align-items: center;
  min-height: 2.75rem;
}

html.js .static-demo {
  display: none;
}

@keyframes demo-panel-enter {
  from {
    opacity: 0;
    transform: translateY(0.45rem);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (hover: hover) and (pointer: fine) {
  .learning-lab button:active:not(:focus-visible) {
    transform: scale(0.97);
    transition-duration: 160ms;
  }
}

@media (max-width: 72rem) and (min-width: 52.001rem) {
  main {
    display: block;
  }

  .hero {
    min-height: auto;
    padding-block: 6rem;
  }

  .hero-copy {
    max-width: 52rem;
  }

  .demo-section {
    min-height: 0;
    margin-bottom: 2rem;
  }

  .demo-invitation {
    min-height: 0;
    margin-bottom: 2rem;
  }

  .lab-workspace {
    grid-template-columns: minmax(8rem, 0.45fr) minmax(24rem, 1.45fr) minmax(
        15rem,
        0.7fr
      );
  }
}

@media (max-width: 52rem) {
  .demo-page main {
    padding-inline: var(--page-gutter);
  }

  .demo-page .demo-section {
    width: 100%;
    margin-block: 1rem 2rem;
    padding: 1.5rem 1.25rem;
  }

  .demo-page .demo-heading h1 {
    font-size: clamp(2.5rem, 12vw, 3.75rem);
  }

  .learning-lab {
    margin-top: 1.25rem;
  }

  .lab-topbar {
    grid-template-columns: minmax(0, 1fr) auto;
  }

  .lab-topbar > p {
    grid-column: 1 / -1;
    grid-row: 2;
    padding-top: 0.55rem;
    border-top: 1px solid #36405a;
  }

  .lab-workspace {
    grid-template-columns: 1fr;
  }

  .lab-route {
    grid-template-columns: repeat(4, minmax(8.25rem, 1fr));
    align-content: initial;
    overflow-x: auto;
    padding: 0.85rem 1rem;
    border-right: 0;
    border-bottom: 1px solid #36405a;
    scroll-snap-type: x proximity;
  }

  .lab-route li {
    grid-template-columns: 1.8rem minmax(0, 1fr);
    min-height: 3.5rem;
    scroll-snap-align: start;
  }

  .lab-route li > span {
    width: 1.8rem;
    height: 1.8rem;
  }

  .lab-route li::before {
    top: 50%;
    right: -0.2rem;
    bottom: auto;
    left: 2rem;
    width: calc(100% - 1.8rem);
    height: 1px;
  }

  .lab-center {
    grid-template-rows: auto auto;
  }

  .lab-activity,
  .lab-activity > section {
    min-height: 0;
  }

  .lab-context {
    border-top: 1px solid #36405a;
    border-left: 0;
  }

  [data-pack-inspector] pre {
    max-height: 19rem;
  }
}

@media (max-width: 30rem) {
  .lab-topbar > div {
    display: grid;
    gap: 0.1rem;
  }

  .lab-topbar span {
    font-size: 0.62rem;
  }

  .molecule-choices {
    grid-template-columns: 1fr;
  }

  .molecule-choices label + label {
    border-top: 1px solid #36405a;
    border-left: 0;
  }

  .choice-set label > span {
    justify-content: flex-start;
  }

  .demo-actions {
    display: grid;
    grid-template-columns: 1fr;
  }

  .demo-actions button {
    width: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  .lab-activity > section {
    animation: none;
  }

  .molecule {
    transition: none;
  }

  .learning-lab button,
  .choice-set label > span {
    transition: none;
  }
}