/* Grid children must shrink before their own scroll containers can scroll. */
:is(
    .explore-workspace,
    .saved-workspace,
    .glossary-workspace,
    .tree-workspace,
    .about-workspace,
    .lab-workspace,
    .teacher-workspace,
    .nearby-workspace,
    .learn-workspace,
    .quiz-workspace
  )
  > * {
  min-width: 0;
}
.teacher-mode {
  display: grid;
  gap: 0.7rem;
}
.teacher-tips {
  margin-top: 1.5rem;
}
.teacher-tips summary {
  font-size: 1.05rem;
}
/* Page-specific layouts. Mobile keeps the same reading and keyboard order. */
main > .page-head,
.explore-heading {
  margin: 1.5rem 0 2rem;
  padding: clamp(1.5rem, 3vw, 2.5rem);
  background: var(--cream);
  border: 1px solid var(--line);
  border-radius: 24px;
}
.page-head h1,
.explore-heading h1 {
  font-size: clamp(2rem, 3.8vw, 3.3rem);
  max-width: 22ch;
}
.page-head p,
.explore-heading p {
  max-width: 65ch;
  margin-bottom: 0;
}
.page-brand {
  right: 2rem;
  width: 64px;
  height: 64px;
}
.section-nav {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 1.3rem 0;
}
.section-nav > .eyebrow {
  margin-right: 0.8rem;
}
.section-nav a {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.7rem 0.9rem;
  min-height: 44px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: #fff;
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 650;
}
.section-nav a span {
  color: var(--muted);
  font-size: 0.75rem;
}
.section-nav a:hover {
  background: var(--cream);
  border-color: var(--green);
}
[id] {
  scroll-margin-top: 6rem;
}
.explore-workspace,
.saved-workspace,
.glossary-workspace,
.tree-workspace,
.about-workspace,
.lab-workspace {
  display: grid;
  grid-template-columns: 210px minmax(0, 1fr);
  gap: clamp(1.2rem, 2.5vw, 2rem);
  align-items: start;
}
.explore-sidebar,
.glossary-sidebar,
.tree-position,
.about-workspace > .section-nav,
.lab-tabs,
.saved-workspace > .tabs-nav {
  position: sticky;
  top: 6rem;
}
.explore-content,
.glossary-content,
.nearby-content,
.about-content,
.lab-content,
.tree-children,
#saved-body {
  min-width: 0;
}
.explore-sidebar,
.lab-workspace > .lab-tabs {
  max-height: calc(100dvh - 7rem);
  overflow-y: auto;
}
/* Explore: a persistent group selector beside results, not above every row. */
.explore-sidebar {
  background: #fff;
  border: 1px solid var(--line);
  padding: 1rem;
  border-radius: var(--radius);
}
.explore-sidebar .group-pills {
  display: grid;
  gap: 0.35rem;
  margin: 0;
}
.explore-sidebar .group-pill {
  border-radius: 10px;
  padding: 0.65rem 0.8rem;
}
.explore-sidebar .small-title {
  margin: 0 0 0.8rem;
  color: var(--muted);
}
.explore-content .catalog-tools {
  margin-top: 0;
  padding: 0 0 1rem;
  border-bottom: 1px solid var(--line);
}
.explore-content .discovery-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}
main[data-page='search'] > .search-form {
  max-width: none;
  margin-bottom: 1.8rem;
}
.discovery-card .media-frame {
  aspect-ratio: 4 / 3;
}
.discovery-body {
  padding: 1rem 1.1rem 1.7rem;
}
/* Learn: lessons have priority; activity shortcuts are a separate column. */
.learn-workspace {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 2rem;
  align-items: start;
}
.learn-workspace .topic-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}
.lesson-catalog > .section-head h2 {
  font-size: 1.8rem;
}
.mode-banner .actions {
  margin: 0;
  gap: 0.8rem;
}
.catalog-tools {
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr) auto;
  gap: 0.8rem;
  align-items: end;
  padding: 1.1rem;
  margin: 1.2rem 0 1.7rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: #fff;
}
.catalog-tools > * {
  min-width: 0;
}
.catalog-tools label {
  display: block;
  margin-bottom: 0.4rem;
  font-size: 0.85rem;
  font-weight: 650;
}
.catalog-tools select,
.catalog-tools input {
  width: 100%;
  min-width: 0;
  min-height: 44px;
  font-size: 0.9rem;
}
.catalog-search > div {
  position: relative;
}
.catalog-search .icon {
  position: absolute;
  top: 50%;
  left: 0.8rem;
  transform: translateY(-50%);
  pointer-events: none;
  color: var(--muted);
}
.catalog-search input {
  padding-left: 2.5rem;
}
.catalog-count {
  grid-column: 1 / -1;
  margin: 0;
  padding-top: 0.7rem;
  border-top: 1px solid var(--line);
}
.catalog-empty {
  padding: 2rem 1rem;
  text-align: center;
  border: 1px dashed var(--line);
  border-radius: var(--radius);
  background: var(--soft);
}
.catalog-empty h3 {
  margin-bottom: 0.4rem;
}
.lesson-catalog .field-group + .field-group {
  padding-top: 1.5rem;
  border-top: 1px solid var(--line);
}
.lesson-catalog .field-icon {
  display: grid;
  place-items: center;
  flex: 0 0 2.8rem;
  height: 2.8rem;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--cream);
  font-size: 1.4rem;
}
.lesson-catalog .topic-card {
  flex-direction: row;
  align-items: flex-start;
  gap: 0.9rem;
  padding: 1.1rem;
}
.lesson-catalog .topic-icon {
  flex: 0 0 2.4rem;
  width: 2.4rem;
  height: 2.4rem;
  font-size: 1.4rem;
}
.lesson-catalog .topic-text {
  min-width: 0;
}
.learn-workspace .action-grid {
  grid-template-columns: 1fr;
}
.learning-tools {
  padding: 1.5rem;
  margin-top: 2.4rem;
  border-radius: var(--radius);
  background: var(--soft);
}
.learning-tools .action-card {
  padding: 0.9rem;
  background: #fff;
  border-color: var(--line);
  border-radius: 12px;
}
.learning-tools .action-card strong {
  font-size: 0.95rem;
}
.learning-tools .action-icon {
  width: 2.5rem;
  height: 2.5rem;
  background: var(--cream);
}
.learning-tools .section-head h2 {
  font-size: 1.6rem;
}
.topic-layout {
  grid-template-columns: minmax(0, 1fr) 290px;
  gap: 1.5rem;
  align-items: start;
}
.topic-side {
  position: sticky;
  top: 6rem;
}
.topic-body .prose,
.topic-body .prose-list {
  max-width: 65ch;
}
.topic-card {
  flex-direction: column;
  padding: 1.4rem;
}
.topic-text {
  flex: 1;
}
.topic-meta {
  margin-top: 1rem;
}
/* Species: identity and actions precede the photograph on a phone. */
.species-hero {
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
  gap: 2rem;
  align-items: start;
}
.species-hero > * {
  min-width: 0;
}
.species-intro {
  padding: 1.6rem;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.species-intro h1 {
  font-family: var(--serif);
  font-weight: 500;
  font-size: clamp(2rem, 3.3vw, 3.2rem);
}
.species-visual .gallery-stage {
  aspect-ratio: 1;
}
.species-intro .actions > * {
  min-width: 0;
  overflow-wrap: anywhere;
}
.species-intro .actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
}
.species-intro .actions > :first-child {
  grid-column: 1 / -1;
}
.dossier-tabs {
  border: 1px solid var(--line);
}
.detail-grid {
  grid-template-columns: minmax(0, 1fr) 260px;
  gap: 1.5rem;
}
/* Lab: left experiment menu, controls beside the result, notes below. */
.lab-tabs {
  display: grid;
  gap: 0.45rem;
  margin: 0;
}
.lab-tabs button {
  text-align: left;
  display: flex;
  align-items: center;
  gap: 0.7rem;
  padding: 0.8rem;
}
.lab-tabs button span {
  font-size: 1.5rem;
}
.lab-grid {
  grid-template-columns: 1fr;
}
.lab-card {
  padding: clamp(1.2rem, 2.5vw, 2rem);
}
.lab-experiment {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 1.5rem;
  align-items: start;
}
.lab-experiment > * {
  min-width: 0;
}
.lab-experiment-sequence {
  grid-template-columns: minmax(0, 1fr);
}
.lab-experiment-sequence #lab-panel {
  max-width: 65ch;
}
#lab-output {
  padding: 1rem;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 16px;
}
.lab-guide {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
}
.lab-guide > div {
  min-width: 0;
}
.lab-guide textarea {
  margin-top: 0.6rem;
}
/* Teachers: the class context and tips stay separate from the form. */
.teacher-workspace {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  gap: 2rem;
  align-items: start;
}
.teacher-context {
  padding: 1.4rem;
  background: var(--soft);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.teacher-context .teacher-level {
  margin: 0;
}
.teacher-context .section {
  padding-bottom: 0;
}
.teacher-context h2 {
  font-size: 1.3rem;
}
.teacher-context .tip-list {
  font-size: 0.88rem;
}
.teacher-workspace .builder {
  margin: 0;
  padding: clamp(1.2rem, 3vw, 2rem);
}
.form-step {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  border-top: 1px solid var(--line);
  padding-top: 1.2rem;
  margin-top: 0.4rem;
}
.form-step span {
  display: grid;
  place-items: center;
  flex-shrink: 0;
  width: 2rem;
  height: 2rem;
  border-radius: 50%;
  background: var(--cream);
  color: var(--green);
  font-size: 0.8rem;
  font-weight: 750;
}
.form-step h3 {
  font-size: 1rem;
  margin: 0;
}
#assignment-output:not(:empty) {
  margin-top: 1.5rem;
  padding: 1.2rem;
  border: 1px solid var(--green);
  background: var(--cream);
  border-radius: 14px;
}
/* Collection: clear local navigation with room for the actual collection. */
.saved-workspace > .tabs-nav {
  display: grid;
  gap: 0.4rem;
  padding: 0.6rem;
  border-radius: 16px;
}
.saved-workspace .tabs-nav a {
  padding: 0.9rem;
  border-radius: 10px;
}
#saved-body .stats {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}
#saved-body .stat {
  background: #fff;
}
#saved-body .badge-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}
#saved-body > .section {
  padding: 1.8rem 0;
}
/* Glossary: search and alphabet remain handy beside readable entries. */
.glossary-workspace {
  grid-template-columns: 250px minmax(0, 1fr);
}
.glossary-sidebar {
  background: var(--soft);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1rem;
}
.glossary-tools {
  display: grid;
  gap: 0.5rem;
}
.glossary-tools input {
  min-width: 0;
}
.alphabet {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
}
.alphabet a {
  width: 100%;
  min-height: 44px;
  background: #fff;
  border: 1px solid var(--line);
}
.letter-group {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin-bottom: 2rem;
}
.letter-group h2 {
  grid-column: 1 / -1;
  margin: 0;
  padding: 0.5rem 0;
  font-size: 2rem;
}
.term-entry {
  min-width: 0;
  background: #fff;
  padding: 1.2rem;
  border: 1px solid var(--line);
  border-radius: 16px;
}
.term-entry h3 small {
  display: block;
  margin: 0.4rem 0 0.8rem;
}
.term-entry .chip {
  white-space: normal;
}
/* Taxonomy: the learner's position is a vertical path on wider screens. */
.tree-position .rank-ladder {
  display: grid;
  gap: 0;
  margin: 0;
}
.tree-position .rank-ladder li {
  border-radius: 0;
  padding: 0.8rem 1rem;
  border: 0;
  border-left: 3px solid var(--line);
}
.tree-position .rank-ladder li.here {
  border-color: var(--green);
  border-radius: 0 12px 12px 0;
}
.tree-children .taxon-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}
.tree-children > .actions {
  margin-top: 0;
}
/* Nearby, quizzes, comparison and reference pages each keep a clear focus. */
.nearby-workspace {
  display: grid;
  grid-template-columns: 310px minmax(0, 1fr);
  gap: 1.5rem;
  align-items: start;
}
.nearby-tools {
  position: sticky;
  top: 6rem;
}
.nearby-tools .inline-field {
  flex-wrap: wrap;
}
.nearby-tools .inline-field input {
  flex-basis: 100%;
}
.nearby-tools .btn {
  width: 100%;
}
.nearby-content > .group-pills {
  margin-top: 0;
}
.nearby-content > #results > .center {
  padding: 4rem 2rem;
  border: 1px dashed var(--line);
  border-radius: var(--radius);
  background: #fff;
}
.quiz-workspace {
  display: grid;
  grid-template-columns: minmax(240px, 0.65fr) minmax(0, 1.35fr);
  gap: 2rem;
  align-items: start;
}
.quiz-workspace > .feature-card {
  flex-direction: column;
  align-items: flex-start;
  padding: 2rem;
  margin: 0;
  position: sticky;
  top: 6rem;
}
.quiz-workspace > .section {
  padding-top: 0;
}
.quiz-workspace .topic-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}
.photo-game {
  max-width: none;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 1rem 2rem;
  align-items: start;
}
.photo-game .quiz-num {
  grid-column: 1 / -1;
  margin: 0;
}
.photo-game .game-photo {
  grid-column: 1;
  grid-row: 2 / 4;
  margin: 0;
  max-height: 500px;
}
.photo-game > .quiz-options {
  grid-column: 2;
  grid-template-columns: 1fr;
  margin: 0;
}
.photo-game > .game-feedback {
  grid-column: 2;
  margin: 0;
}
.photo-game > .quiz-result {
  grid-column: 1 / -1;
}
main[data-page='quiz'] > .quiz {
  max-width: 840px;
  margin-inline: auto;
}
.compare-pickers {
  background: #fff;
  padding: 1.5rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.compare-summary {
  margin-top: 1.5rem;
}
.compare-table {
  table-layout: fixed;
}
.compare-table thead th:first-child {
  width: 20%;
}
.compare-table td {
  overflow-wrap: anywhere;
}
.compare-photo {
  max-width: none;
  aspect-ratio: 16 / 10;
}
.geo-timeline {
  padding: 1.5rem;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.period-section {
  display: grid;
  grid-template-columns: 190px minmax(0, 1fr);
  gap: 1.5rem;
  align-items: start;
  padding-top: 1rem;
  border-top: 1px solid var(--line);
}
.period-title {
  font-size: 1.3rem;
  margin: 0;
  position: sticky;
  top: 6rem;
}
.period-title small {
  flex-basis: 100%;
  line-height: 1.5;
}
.period-section.recent {
  display: block;
}
.period-section.recent .period-title {
  position: static;
  margin-bottom: 1rem;
}
.about-workspace > .section-nav {
  display: grid;
  margin: 0;
}
.about-content > .grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}
.about-content > .section {
  border-top: 1px solid var(--line);
  margin-top: 2rem;
  padding: 1.5rem 0 0;
}
.about-content p {
  max-width: 70ch;
}
main[data-page='tugas'] {
  max-width: 960px;
}
.assignment-questions {
  padding: 0;
  list-style: none;
  counter-reset: answer;
}
.assignment-questions > li {
  counter-increment: answer;
  padding: 1.5rem;
  margin: 1rem 0;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 16px;
}
.assignment-questions > li > p::before {
  content: counter(answer) '. ';
  color: var(--green);
  font-weight: 750;
}

/* Biology map: a persistent guide beside the atlas, with a single reading order. */
.biomap-workspace {
  display: grid;
  grid-template-columns: 220px minmax(0, 1fr);
  gap: 2rem;
  align-items: start;
}
.biomap-workspace > * {
  min-width: 0;
}
.biomap-navigation {
  position: sticky;
  top: 6rem;
  max-height: calc(100dvh - 7rem);
  overflow-y: auto;
  padding: 1rem;
  background: var(--soft);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.biomap-navigation .section-nav {
  display: grid;
  margin: 0 0 1rem;
}
.biomap-navigation .section-nav > .eyebrow {
  margin: 0 0 0.5rem;
}
.biomap-navigation .btn {
  width: 100%;
}
.biomap-content > .section:first-child {
  padding-top: 0;
}
.biomap-content .section-head h2 {
  font-size: clamp(1.6rem, 2.8vw, 2.2rem);
}
.biomap-content .field-map,
.biomap-content .branch-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}
.biomap-content .card {
  min-width: 0;
  padding: 1.3rem;
}
.biomap-content .field-card {
  border-top: 4px solid var(--green);
}
.biomap-content .field-topics li {
  display: grid;
  gap: 0.35rem;
  padding: 0.65rem 0;
  border-bottom: 1px solid var(--line);
}
.biomap-content .field-topics li:last-child {
  border: 0;
}
.biomap-content .org-step {
  padding: 1.3rem;
  border-radius: var(--radius);
}
.org-index {
  min-width: 2rem;
}
.org-more {
  margin-top: 0.6rem;
}
.org-more summary {
  width: fit-content;
  min-height: 44px;
  padding: 0.6rem 0;
  font-size: 0.85rem;
  font-weight: 650;
  color: var(--green);
  cursor: pointer;
}
.biomap-content .coverage-table {
  width: 100%;
  table-layout: fixed;
  font-size: 0.9rem;
}
.biomap-content .coverage-table th,
.biomap-content .coverage-table td {
  white-space: normal;
  overflow-wrap: anywhere;
}
.biomap-content .stat-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
}
.biomap-content .stat-list div {
  display: flex;
  flex-direction: column-reverse;
  justify-content: end;
  padding: 1rem;
}
.biomap-content .stat-list dd {
  font-family: var(--serif);
  font-size: 2.2rem;
  font-weight: 500;
}

/* Tablet: controls become compact rows; reading panels retain useful width. */
@media (max-width: 1100px) {
  .explore-workspace,
  .tree-workspace,
  .saved-workspace,
  .about-workspace,
  .lab-workspace {
    grid-template-columns: 180px minmax(0, 1fr);
    gap: 1rem;
  }
  .explore-content .discovery-grid,
  .tree-children .taxon-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .learn-workspace {
    grid-template-columns: minmax(0, 1fr) 260px;
    gap: 1rem;
  }
  .learn-workspace .topic-grid {
    grid-template-columns: 1fr;
  }
  .catalog-tools {
    grid-template-columns: minmax(0, 1fr) auto;
  }
  .catalog-search {
    grid-column: 1 / -1;
  }
  .biomap-workspace {
    grid-template-columns: 190px minmax(0, 1fr);
    gap: 1rem;
  }
  .biomap-content .field-map,
  .biomap-content .branch-grid {
    grid-template-columns: minmax(0, 1fr);
  }
  .lab-experiment,
  .lab-guide {
    grid-template-columns: 1fr;
  }
  .teacher-workspace {
    grid-template-columns: 240px minmax(0, 1fr);
    gap: 1rem;
  }
  .glossary-workspace {
    grid-template-columns: 220px minmax(0, 1fr);
    gap: 1rem;
  }
  .letter-group {
    grid-template-columns: 1fr;
  }
  .species-hero {
    gap: 1rem;
  }
  .species-intro {
    padding: 1.2rem;
  }
  .topic-layout {
    grid-template-columns: minmax(0, 1fr) 260px;
  }
  .nearby-workspace {
    grid-template-columns: 270px minmax(0, 1fr);
  }
}
@media (max-width: 800px) {
  main > .page-head,
  .explore-heading {
    margin-top: 1rem;
    padding: 1.4rem;
  }
  .explore-workspace,
  .saved-workspace,
  .glossary-workspace,
  .tree-workspace,
  .about-workspace,
  .lab-workspace,
  .teacher-workspace,
  .nearby-workspace,
  .learn-workspace,
  .quiz-workspace,
  .biomap-workspace,
  .topic-layout {
    grid-template-columns: 1fr;
  }
  .explore-sidebar,
  .glossary-sidebar,
  .tree-position,
  .about-workspace > .section-nav,
  .lab-tabs,
  .saved-workspace > .tabs-nav,
  .nearby-tools,
  .topic-side,
  .biomap-navigation,
  .quiz-workspace > .feature-card {
    position: static;
  }
  .explore-sidebar {
    max-height: none;
    overflow: visible;
    padding: 0;
    background: none;
    border: 0;
  }
  .explore-sidebar .small-title {
    margin-bottom: 0.4rem;
  }
  .explore-sidebar .group-pills {
    display: flex;
    flex-wrap: nowrap;
    overflow-x: auto;
    padding: 0.35rem 0.2rem 0.7rem;
  }
  .explore-sidebar .group-pill {
    flex-shrink: 0;
  }
  .lab-tabs {
    display: flex;
    flex-wrap: nowrap;
    overflow-x: auto;
    gap: 0.5rem;
    padding: 0.3rem 0.2rem 0.8rem;
    scroll-padding-inline: 0.2rem;
  }
  .lab-tabs button {
    flex: 0 0 auto;
    max-width: 80%;
    min-height: 48px;
    font-size: 0.85rem;
  }
  .biomap-navigation {
    max-height: none;
  }
  .biomap-navigation .section-nav {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .biomap-navigation .section-nav > .eyebrow {
    grid-column: 1 / -1;
  }
  .biomap-navigation .btn {
    width: auto;
  }
  .saved-workspace > .tabs-nav {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .saved-workspace .tabs-nav a {
    padding: 0.7rem 0.4rem;
    text-align: center;
    font-size: 0.85rem;
  }
  .learn-workspace .topic-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .learning-tools {
    margin: 0;
  }
  .learning-tools .action-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .teacher-context {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    align-items: start;
  }
  .teacher-context .section {
    padding: 0;
  }
  .teacher-context .tip-list {
    margin-bottom: 0;
  }
  .glossary-tools {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
  }
  .alphabet {
    display: flex;
    flex-wrap: nowrap;
    overflow-x: auto;
    padding-bottom: 0.5rem;
    margin-bottom: 0;
  }
  .alphabet a {
    flex: 0 0 44px;
  }
  .tree-position .rank-ladder {
    display: flex;
    flex-wrap: nowrap;
    overflow-x: auto;
    padding-bottom: 0.5rem;
  }
  .tree-position .rank-ladder li {
    flex-shrink: 0;
    border-left: 0;
    border-bottom: 3px solid var(--line);
  }
  .tree-position .rank-ladder li.here {
    border-color: var(--green);
    border-radius: 10px 10px 0 0;
  }
  .about-workspace > .section-nav {
    display: flex;
  }
  .about-workspace > .section-nav .eyebrow {
    flex-basis: 100%;
  }
  .species-hero {
    grid-template-columns: 1fr;
  }
  .species-intro {
    display: contents;
  }
  .species-identity {
    grid-row: 1;
  }
  .species-visual {
    grid-row: 2;
  }
  .species-details {
    grid-row: 3;
    min-width: 0;
    background: #fff;
    padding: 1.2rem;
    border: 1px solid var(--line);
    border-radius: var(--radius);
  }
  .species-identity h1 {
    margin-bottom: 0.3rem;
  }
  .species-identity > p {
    margin-bottom: 0;
  }

  .species-visual .gallery-stage {
    aspect-ratio: 4 / 3;
  }
  .detail-grid {
    grid-template-columns: 1fr;
  }
  .period-section {
    grid-template-columns: 1fr;
  }
  .period-title {
    position: static;
  }
  .quiz-workspace > .feature-card {
    flex-direction: row;
    flex-wrap: wrap;
    padding: 1.4rem;
  }
  .quiz-workspace > .feature-card > span:nth-child(2) {
    flex: 1 1 200px;
  }
}
@media (max-width: 540px) {
  .biomap-content .org-step {
    padding: 1rem;
  }
  .biomap-navigation .section-nav,
  .biomap-content .stat-list {
    grid-template-columns: minmax(0, 1fr);
  }
  .biomap-content .stat-list div {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
  }
  .biomap-content .coverage-table th,
  .biomap-content .coverage-table td {
    padding: 0.6rem 0.4rem;
  }
  .page-head h1,
  .explore-heading h1 {
    font-size: clamp(1.8rem, 8vw, 2.4rem);
  }
  .page-head p,
  .explore-heading p {
    font-size: 0.95rem;
  }
  main > .page-head,
  .explore-heading {
    border-radius: 16px;
    padding: 1.2rem;
    margin-bottom: 1.3rem;
  }
  .hero {
    gap: 1rem;
    padding-top: 1.6rem;
  }
  .hero-copy > p {
    font-size: 1rem;
  }
  .hero-copy h1 {
    font-size: clamp(2.3rem, 10vw, 3rem);
  }
  .hero-mosaic {
    grid-template-rows: 135px 135px;
  }
  .hero-primary {
    border-radius: 50px 18px 18px 18px;
  }
  .hero-links {
    gap: 0.8rem;
  }
  .section {
    padding: 1.6rem 0;
  }
  .section-head {
    gap: 0.6rem;
  }
  .search-form {
    display: grid;
    grid-template-columns: auto minmax(0, 1fr) auto;
    gap: 0.25rem;
  }
  .search-form input {
    font-size: 0.9rem;
  }
  .search-form .btn {
    padding-inline: 0.8rem;
  }
  .search-form select {
    grid-column: 1 / -1;
    grid-row: 2;
    width: 100%;
    max-width: none;
    border-left: 0;
    border-top: 1px solid var(--line);
  }
  .hero-search input {
    font-size: 0.9rem;
  }
  .section-nav {
    gap: 0.4rem;
  }
  .section-nav > .eyebrow {
    width: 100%;
  }
  .section-nav a {
    padding: 0.6rem;
    font-size: 0.8rem;
    gap: 0.4rem;
  }
  .topic-card {
    flex-direction: row;
    padding: 1rem;
  }
  .learn-workspace .topic-grid,
  .quiz-workspace .topic-grid,
  .learning-tools .action-grid {
    grid-template-columns: 1fr;
  }
  .learning-tools {
    padding: 1rem;
  }
  .teacher-context {
    display: block;
  }
  .teacher-context .section {
    margin-top: 1.3rem;
  }
  .teacher-context .tip-list {
    font-size: 0.9rem;
  }
  .teacher-workspace .form-grid {
    grid-template-columns: 1fr;
  }
  .form-step h3 {
    font-size: 0.95rem;
  }
  .lab-tabs {
    display: flex;
    overflow-x: auto;
    padding: 0.25rem 0.15rem 0.6rem;
    scroll-snap-type: x proximity;
  }
  .lab-tabs button {
    flex: 0 0 10rem;
    scroll-snap-align: start;
  }

  .lab-tabs button {
    flex-direction: row;
    align-items: center;
    font-size: 0.8rem;
  }
  .lab-tabs button span {
    font-size: 1.2rem;
  }
  .lab-experiment {
    gap: 1rem;
  }
  .lab-card,
  .lab-guide {
    padding: 1rem;
  }
  #lab-output {
    padding: 0.7rem;
  }
  .photo-game {
    grid-template-columns: 1fr;
    padding: 1rem;
  }
  .photo-game .game-photo,
  .photo-game > .quiz-options,
  .photo-game > .game-feedback {
    grid-column: 1;
    grid-row: auto;
  }
  .photo-game .game-photo {
    aspect-ratio: 4 / 3;
    max-height: 300px;
  }
  .photo-game > .quiz-options {
    grid-template-columns: 1fr 1fr;
    gap: 0.6rem;
  }
  .photo-game .quiz-option {
    padding: 0.8rem;
    font-size: 0.9rem;
  }
  .glossary-tools {
    grid-template-columns: 1fr;
  }
  .term-entry {
    padding: 1rem;
  }
  .tree-children .taxon-grid {
    grid-template-columns: 1fr;
  }
  .explore-content .discovery-grid {
    gap: 0.65rem;
  }
  .discovery-body {
    padding: 0.8rem 0.65rem 1.6rem;
  }
  .discovery-body h3 {
    font-size: 0.95rem;
  }
  .catalog-tools {
    gap: 0.6rem;
  }
  .catalog-tools .segmented {
    width: 100%;
  }
  .catalog-tools .segmented a {
    flex: 1;
    text-align: center;
  }
  .species-intro {
    padding: 1rem;
  }
  .species-intro .actions {
    gap: 0.5rem;
  }
  .species-intro .actions .btn {
    padding-inline: 0.6rem;
    font-size: 0.85rem;
  }
  .dossier-tabs button {
    padding: 0.7rem 0.8rem;
    font-size: 0.85rem;
  }
  #saved-body .stats,
  #saved-body .badge-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .saved-workspace > .tabs-nav {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .compare-pickers {
    padding: 1rem;
  }
  .compare-table {
    min-width: 0;
  }
  .compare-table tr {
    display: grid;
    grid-template-columns: 1fr 1fr;
  }
  .compare-table th:first-child {
    grid-column: 1 / -1;
    width: auto;
    padding: 0.6rem;
    background: var(--soft);
  }
  .compare-table thead th:first-child {
    display: none;
  }
  .compare-table td,
  .compare-table th {
    min-width: 0;
    padding: 0.7rem;
    font-size: 0.85rem;
  }
  .compare-table td + td {
    border-left: 1px solid var(--line);
  }
  .about-content > .grid {
    grid-template-columns: 1fr;
  }
  .geo-timeline {
    padding: 1rem;
  }
  .assignment-questions > li {
    padding: 1rem;
  }
}
@media print {
  main > .page-head {
    background: none;
    border: 0;
    padding: 0;
  }
  .section-nav,
  .explore-sidebar,
  .tree-position,
  .glossary-sidebar,
  .teacher-context {
    display: none !important;
  }
  .teacher-workspace,
  .lab-workspace,
  .lab-experiment,
  .lab-guide,
  .topic-layout,
  .about-workspace,
  .saved-workspace,
  .photo-game {
    display: block;
  }
  .topic-side {
    position: static;
  }
  .topic-body,
  .species-intro {
    border: 0;
    padding: 0;
  }
  .assignment-questions > li {
    break-inside: avoid;
  }
}

/* Teacher targets stay visible; native radios support touch and arrow keys. */
.sheet-dialog .teacher-level {
  min-width: 0;
  margin-inline: 0;
  border: 1px solid var(--line);
  background: #effcf7;
}
.teacher-level legend {
  padding: 0 0.4rem;
  font-weight: 750;
  font-size: 0.95rem;
}
.teacher-level-options {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.6rem;
}
.teacher-level-choice {
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
  padding: 0.8rem 0.6rem;
  border: 2px solid var(--line);
  border-radius: 12px;
  background: #fff;
  cursor: pointer;
  min-width: 0;
}
.teacher-level-choice:has(:checked) {
  border-color: var(--green);
  background: #d8f8e9;
}
.teacher-level-choice:focus-within {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
}
.teacher-level-choice input {
  margin: 0.25rem 0 0;
  accent-color: var(--green);
  flex-shrink: 0;
}
.teacher-level-choice strong,
.teacher-level-choice small {
  display: block;
}
.teacher-level-choice small {
  font-size: 0.72rem;
  color: var(--muted);
  line-height: 1.4;
  margin-top: 0.3rem;
}
main > .page-head,
.explore-heading {
  background: linear-gradient(120deg, #ddf9ec, #edfcf6 65%, #effbd5);
}
main[data-page='lab'] > .page-head {
  background: linear-gradient(120deg, #dff5ff, #eefafc 65%, #e6fbe8);
}
main[data-page='quiz'] > .page-head {
  background: linear-gradient(120deg, #eee4ff, #f9f2ff 65%, #ffe9dc);
}
main[data-page='guru'] > .page-head {
  background: linear-gradient(120deg, #e7f7d4, #f5fce9 65%, #dff8ed);
}
@media (max-width: 540px) {
  .teacher-level-options {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

/* Voluntary support stays outside the learning and assessment flows. */
.support-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.8fr);
  gap: 1.5rem;
  align-items: start;
}
.support-grid > * {
  min-width: 0;
  padding: clamp(1.2rem, 3vw, 2rem);
}
.support-mark {
  width: 72px;
  height: 72px;
  margin-bottom: 1rem;
}
.support-promise {
  background: var(--cream);
}
.support-donation .notice p {
  margin-bottom: 0;
}
.support-donation .source-meta {
  overflow-wrap: anywhere;
}
.support-ways {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}
/* Three columns are narrow on tablets; a long link wraps instead of widening the page. */
.support-ways .text-link {
  white-space: normal;
}
.support-banner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1.2rem;
  padding: clamp(1.2rem, 3vw, 2rem);
  margin: 1.5rem 0;
  background: var(--cream);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.support-banner > div {
  flex: 1 1 20rem;
}
.support-banner h2 {
  font-size: 1.5rem;
  margin-bottom: 0.4rem;
}
.support-banner p {
  max-width: 60ch;
  margin: 0;
  color: var(--muted);
}
@media (max-width: 700px) {
  .support-grid,
  .support-ways {
    grid-template-columns: 1fr;
  }
}

.support-channels {
  display: grid;
  gap: 1rem;
  margin: 1rem 0;
}
.support-channel {
  min-width: 0;
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper);
}
.support-channel h4 {
  margin: 0 0 0.8rem;
  font-size: 1rem;
}
.support-channel .btn {
  white-space: normal;
  text-align: center;
}
.support-channel .source-meta {
  margin-bottom: 0;
}
.support-help summary {
  cursor: pointer;
  font-weight: 700;
}