.senior-library-page {
  --senior-ink: var(--library-ink);
  --senior-muted: var(--library-muted);
  --senior-line: var(--library-line);
  --senior-soft: rgba(15, 54, 58, 0.06);
  --senior-accent: var(--library-teal);
  --senior-accent-soft: rgba(15, 107, 104, 0.1);
  --senior-warm: var(--library-amber);
  min-height: 100vh;
  overflow-x: hidden;
}

.senior-library-page a {
  color: inherit;
}

.senior-library-page .sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.senior-library-shell {
  width: min(1180px, calc(100% - 56px));
  margin: 0 auto;
  display: grid;
  grid-template-columns: 220px minmax(0, 1fr);
  align-items: start;
  gap: 12px;
  padding: 8px 0 42px;
}

.senior-library-sidebar {
  min-width: 0;
  border: 1px solid rgba(15, 54, 58, 0.1);
  border-radius: 10px;
  background: rgba(255, 252, 246, 0.76);
}

.senior-library-sidebar-inner {
  position: sticky;
  top: 0;
  min-width: 0;
  padding: 14px;
}

.senior-library-sidebar-label {
  margin: 0 0 12px;
  color: var(--senior-muted);
  font-size: 0.75rem;
  font-weight: 700;
}

.senior-library-chapters {
  display: grid;
  gap: 3px;
}

.senior-library-chapter-group {
  min-width: 0;
}

.senior-library-chapter-row {
  display: grid;
  grid-template-columns: 28px minmax(0, 1fr);
  align-items: stretch;
  gap: 0;
}

.senior-library-chapter-toggle {
  display: grid;
  place-items: center;
  align-self: center;
  width: 24px;
  height: 32px;
  padding: 0;
  border: 0;
  border-radius: 5px;
  background: transparent;
  color: var(--senior-muted);
  cursor: pointer;
  font: inherit;
  font-size: 1rem;
  line-height: 1;
}

.senior-library-chapter-toggle:hover {
  background: rgba(15, 107, 104, 0.09);
  color: var(--senior-accent);
}

.senior-library-chapter-toggle.is-empty {
  visibility: hidden;
}

.senior-library-chapter {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: 6px;
  min-height: 44px;
  padding: 6px 9px;
  border: 0;
  border-radius: 6px;
  background: transparent;
  color: #3c484b;
  cursor: pointer;
  text-align: left;
  transition: background 140ms ease, color 140ms ease;
}

.senior-library-chapter:hover {
  background: rgba(15, 107, 104, 0.06);
}

.senior-library-chapter.is-active {
  background: var(--senior-accent-soft);
  color: var(--senior-accent);
  font-weight: 700;
}

.senior-library-chapter.is-parent-active {
  background: rgba(15, 107, 104, 0.055);
  color: var(--senior-accent);
  font-weight: 700;
}

.senior-library-chapter-name {
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.senior-library-chapter-count {
  color: var(--senior-muted);
  font-size: 0.78rem;
  font-variant-numeric: tabular-nums;
}

.senior-library-subchapters {
  display: grid;
  gap: 2px;
  margin: 2px 0 6px 24px;
}

.senior-library-subchapter {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: 8px;
  min-height: 34px;
  padding: 5px 10px;
  border: 0;
  border-radius: 5px;
  background: transparent;
  color: var(--senior-muted);
  cursor: pointer;
  font: inherit;
  font-size: 0.78rem;
  text-align: left;
}

.senior-library-subchapter:hover {
  background: rgba(15, 107, 104, 0.055);
  color: var(--senior-ink);
}

.senior-library-subchapter.is-active {
  background: var(--senior-accent-soft);
  color: var(--senior-accent);
  font-weight: 700;
}

.senior-library-subchapter span:first-child {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.senior-library-subchapter span:last-child {
  color: var(--senior-muted);
  font-variant-numeric: tabular-nums;
}

.senior-library-subchapter-group {
  min-width: 0;
}

.senior-library-modules {
  display: grid;
  gap: 2px;
  margin: 2px 0 7px 14px;
  padding-left: 8px;
  border-left: 1px solid rgba(15, 107, 104, 0.16);
}

.senior-library-module {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 6px;
  min-height: 31px;
  padding: 5px 8px;
  border: 0;
  border-radius: 5px;
  background: transparent;
  color: var(--senior-muted);
  cursor: pointer;
  font: inherit;
  font-size: 0.74rem;
  text-align: left;
}

.senior-library-module:hover,
.senior-library-module.is-active {
  background: rgba(15, 107, 104, 0.07);
  color: var(--senior-accent);
}

.senior-library-module.is-active {
  font-weight: 750;
}

.senior-library-module small {
  flex: 0 0 auto;
  color: #a06b26;
  font-size: 0.64rem;
}

.senior-library-content {
  min-width: 0;
  padding: 14px;
  border: 1px solid rgba(15, 54, 58, 0.1);
  border-radius: 10px;
  background: rgba(255, 252, 246, 0.76);
}

.senior-library-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 42px;
  margin-bottom: 14px;
}

.senior-library-heading {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 12px;
  min-width: 0;
}

.senior-library-heading h1 {
  margin: 0;
  color: var(--senior-ink);
  font-family: "Songti SC", "Noto Serif SC", "STSong", serif;
  font-size: 1.32rem;
  font-weight: 750;
  letter-spacing: 0;
  white-space: nowrap;
}

.senior-library-heading span {
  color: var(--senior-muted);
  font-size: 0.82rem;
}

.senior-library-filters {
  display: flex;
  align-items: center;
  gap: 8px;
}

.senior-library-filters[hidden],
.senior-library-sections[hidden],
.senior-library-grid[hidden],
.senior-library-pagination[hidden],
.senior-library-worksheet[hidden],
.senior-learning-view[hidden] {
  display: none !important;
}

.senior-library-filters select {
  height: 34px;
  max-width: 148px;
  padding: 0 30px 0 10px;
  border: 1px solid var(--senior-line);
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.58);
  color: var(--senior-ink);
  font: inherit;
  font-size: 0.82rem;
  cursor: pointer;
}

.senior-library-filters select:focus-visible,
.senior-library-chapter-toggle:focus-visible,
.senior-library-chapter:focus-visible,
.senior-library-section:focus-visible,
.senior-library-subchapter:focus-visible,
.senior-library-module:focus-visible,
.senior-library-collection-entry:focus-visible,
.senior-library-page-button:focus-visible,
.senior-library-card:focus-visible,
.senior-worksheet-solution-link:focus-visible,
.senior-learning-module-card:focus-visible,
.senior-learning-solution-link:focus-visible,
.senior-learning-back-link:focus-visible,
.senior-learning-map-svg a:focus {
  outline: 2px solid var(--senior-accent);
  outline-offset: 2px;
}

.senior-library-sections {
  display: flex;
  gap: 4px;
  overflow-x: auto;
  margin: 0 0 20px;
  padding-bottom: 2px;
  scrollbar-width: thin;
}

.senior-library-section {
  flex: 0 0 auto;
  padding: 7px 11px;
  border: 1px solid transparent;
  border-radius: 999px;
  background: transparent;
  color: var(--senior-muted);
  cursor: pointer;
  font-size: 0.82rem;
}

.senior-library-section:hover {
  border-color: rgba(15, 107, 104, 0.24);
  background: rgba(15, 107, 104, 0.06);
  color: var(--senior-ink);
}

.senior-library-section.is-active {
  border-color: rgba(15, 107, 104, 0.36);
  background: rgba(15, 107, 104, 0.1);
  color: var(--senior-accent);
  font-weight: 700;
}

.senior-library-section span {
  margin-left: 6px;
  color: var(--senior-muted);
  font-size: 0.72rem;
}

.senior-library-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.senior-library-collection-entry {
  grid-column: 1 / -1;
  display: flex;
  min-height: 104px;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 18px 20px;
  border: 1px solid var(--senior-line);
  border-radius: 8px;
  background: rgba(15, 107, 104, 0.045);
  transition: border-color 150ms ease, background 150ms ease;
}

.senior-library-collection-entry:hover {
  border-color: rgba(15, 107, 104, 0.3);
  background: rgba(15, 107, 104, 0.075);
}

.senior-library-collection-entry p,
.senior-library-collection-entry h2,
.senior-library-collection-entry span {
  margin: 0;
}

.senior-library-collection-entry p {
  margin-bottom: 4px;
  color: var(--senior-accent);
  font-size: 0.72rem;
  font-weight: 750;
}

.senior-library-collection-entry h2 {
  margin-bottom: 5px;
  color: var(--senior-ink);
  font-family: "Songti SC", "Noto Serif SC", "STSong", serif;
  font-size: 1.05rem;
  letter-spacing: 0;
}

.senior-library-collection-entry div > span {
  color: var(--senior-muted);
  font-size: 0.78rem;
}

.senior-library-collection-action {
  flex: 0 0 auto;
  color: var(--senior-accent);
  font-size: 0.82rem;
  font-weight: 700;
}

.senior-library-card {
  display: grid;
  grid-template-columns: minmax(128px, 36%) minmax(0, 1fr);
  min-height: 184px;
  overflow: hidden;
  border: 1px solid var(--senior-line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.58);
  transition: border-color 150ms ease, background 150ms ease, transform 150ms ease;
}

.senior-library-card:hover {
  transform: translateY(-1px);
  border-color: rgba(15, 107, 104, 0.3);
  background: rgba(255, 255, 255, 0.82);
}

.senior-library-thumbnail {
  min-width: 0;
  background: rgba(248, 244, 235, 0.9);
}

.senior-library-thumbnail img {
  display: block;
  width: 100%;
  height: 100%;
  min-height: 184px;
  object-fit: cover;
}

.senior-library-card-body {
  display: flex;
  min-width: 0;
  flex-direction: column;
  padding: 15px 16px 13px;
}

.senior-library-card-type {
  margin: 0 0 7px;
  color: var(--senior-accent);
  font-size: 0.75rem;
  font-weight: 750;
}

.senior-library-card h2 {
  display: -webkit-box;
  overflow: hidden;
  margin: 0;
  color: var(--senior-ink);
  font-size: 1rem;
  font-weight: 750;
  line-height: 1.5;
  letter-spacing: 0;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
}

.senior-library-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 5px;
  margin-top: 10px;
}

.senior-library-tag {
  padding: 3px 7px;
  border-radius: 4px;
  background: var(--senior-soft);
  color: var(--senior-muted);
  font-size: 0.69rem;
}

.senior-library-card-footer {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: end;
  gap: 10px;
  margin-top: auto;
  padding-top: 12px;
}

.senior-library-source,
.senior-library-update {
  color: var(--senior-muted);
  font-size: 0.72rem;
  line-height: 1.45;
}

.senior-library-source {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.senior-library-card-meta {
  display: flex;
  align-items: center;
  gap: 9px;
}

.senior-library-difficulty {
  display: inline-flex;
  gap: 3px;
}

.senior-library-difficulty i {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: rgba(15, 54, 58, 0.14);
}

.senior-library-difficulty i.is-filled {
  background: var(--senior-warm);
}

.senior-library-arrow {
  color: var(--senior-accent);
  font-size: 1rem;
}

.senior-library-empty {
  grid-column: 1 / -1;
  min-height: 260px;
  display: grid;
  place-content: center;
  justify-items: center;
  border-top: 1px solid var(--senior-line);
  color: var(--senior-muted);
  text-align: center;
}

.senior-library-empty h2 {
  margin: 0 0 8px;
  color: var(--senior-ink);
  font-size: 1.05rem;
}

.senior-library-empty p {
  margin: 0;
  font-size: 0.86rem;
}

.senior-library-pagination {
  display: flex;
  justify-content: center;
  gap: 6px;
  margin-top: 26px;
}

.senior-library-worksheet {
  width: min(100%, 780px);
  margin: 0 auto;
}

.senior-library-collection-tabs {
  display: flex;
  width: fit-content;
  margin: 2px auto 22px;
  padding: 3px;
  border: 1px solid var(--senior-line);
  border-radius: 6px;
  background: rgba(15, 54, 58, 0.045);
}

.senior-library-collection-tabs[hidden] {
  display: none;
}

.senior-library-collection-tab {
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  min-height: 34px;
  padding: 7px 14px;
  border: 0;
  border-radius: 4px;
  background: transparent;
  color: var(--senior-muted);
  cursor: pointer;
}

.senior-library-collection-tab small {
  font-size: 0.68rem;
}

.senior-library-collection-tab.is-active {
  background: #fff;
  color: var(--senior-accent);
  box-shadow: 0 1px 4px rgba(15, 54, 58, 0.12);
  font-weight: 800;
}

.senior-worksheet-group + .senior-worksheet-group {
  margin-top: 32px;
}

.senior-worksheet-group-heading {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 2px;
  padding: 0 4px 9px;
  border-bottom: 1px solid rgba(15, 54, 58, 0.18);
}

.senior-worksheet-group-heading h2 {
  margin: 0;
  color: var(--senior-ink);
  font-size: 0.88rem;
  font-weight: 800;
  letter-spacing: 0;
}

.senior-worksheet-group-heading span {
  color: var(--senior-muted);
  font-size: 0.72rem;
}

.senior-worksheet-problem {
  display: grid;
  grid-template-columns: 30px minmax(0, 1fr);
  gap: 4px;
  padding: 17px 4px 18px;
  border-bottom: 1px solid rgba(15, 54, 58, 0.1);
  color: var(--senior-ink);
}

.senior-worksheet-problem-number {
  padding-top: 1px;
  font-family: "Songti SC", "Noto Serif SC", "STSong", serif;
  font-size: 0.95rem;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
}

.senior-worksheet-problem-body {
  min-width: 0;
}

.senior-worksheet-line {
  font-family: "Songti SC", "Noto Serif SC", "STSong", serif;
  font-size: 0.94rem;
  line-height: 1.9;
}

.senior-worksheet-line + .senior-worksheet-line {
  margin-top: 4px;
}

.senior-worksheet-options {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  align-items: baseline;
  gap: 6px 14px;
  margin-top: 7px;
  font-family: "Songti SC", "Noto Serif SC", "STSong", serif;
  font-size: 0.94rem;
  line-height: 1.8;
}

.senior-worksheet-options.is-stacked {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 3px;
}

.senior-worksheet-option {
  display: inline-flex;
  align-items: baseline;
  min-width: 0;
}

.senior-worksheet-options:not(.is-stacked) .senior-worksheet-option {
  white-space: nowrap;
}

.senior-worksheet-option-label {
  flex: 0 0 auto;
  margin-right: 5px;
}

.senior-worksheet-source {
  color: var(--senior-muted);
  font-size: 0.84rem;
}

.senior-worksheet-solution-link {
  display: inline-flex;
  align-items: center;
  margin-top: 10px;
  color: var(--senior-accent) !important;
  font-size: 0.78rem;
  font-weight: 700;
}

.senior-worksheet-solution-link:hover {
  text-decoration: underline;
  text-underline-offset: 3px;
}

.senior-worksheet-figures {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin: 12px 0 6px;
}

.senior-worksheet-figures.is-single {
  grid-template-columns: minmax(0, 1fr);
  width: min(100%, 620px);
  margin-right: auto;
  margin-left: auto;
}

.senior-worksheet-figure {
  min-width: 0;
  margin: 0;
  padding: 10px;
  border: 1px solid rgba(15, 54, 58, 0.12);
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.48);
}

.senior-worksheet-figure figcaption {
  margin-bottom: 4px;
  color: var(--senior-muted);
  font-size: 0.7rem;
  font-weight: 700;
}

.senior-worksheet-figure svg {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 720 / 500;
}

.senior-worksheet-figure.is-value-table svg {
  aspect-ratio: 720 / 280;
}

.senior-worksheet-figure p {
  margin: 5px 0 0;
  color: var(--senior-muted);
  font-size: 0.68rem;
}

.senior-library-worksheet .inline-math {
  display: inline;
  vertical-align: baseline;
  white-space: nowrap;
}

.senior-library-worksheet .inline-math sub {
  font-size: 0.72em;
  line-height: 0;
}

.senior-library-worksheet .inline-math sup {
  font-size: 0.72em;
  line-height: 0;
  vertical-align: 0.55em;
}

.senior-library-worksheet .math-fraction {
  display: inline-grid;
  grid-template-rows: auto auto;
  align-items: stretch;
  justify-items: stretch;
  min-width: 1.15em;
  margin: 0 0.08em;
  vertical-align: middle;
  line-height: 1;
  text-align: center;
}

.senior-library-worksheet .math-numerator {
  padding: 0 0.12em 0.06em;
  border-bottom: 1.2px solid currentColor;
}

.senior-library-worksheet .math-denominator {
  padding: 0.05em 0.12em 0;
}

.senior-library-worksheet .math-radical {
  display: inline-flex;
  align-items: flex-start;
  vertical-align: -0.12em;
}

.senior-library-worksheet .math-radical-symbol {
  margin-right: -0.05em;
  font-size: 1.18em;
  line-height: 1;
}

.senior-library-worksheet .math-radicand {
  margin-top: 0.06em;
  padding: 0 0.08em 0 0.1em;
  border-top: 1.2px solid currentColor;
  line-height: 1.05;
}

.senior-learning-view {
  min-width: 0;
}

.senior-learning-topic {
  display: grid;
  gap: 24px;
}

.senior-learning-hero,
.senior-learning-module-hero {
  position: relative;
  overflow: hidden;
  padding: 34px;
  border: 1px solid rgba(15, 107, 104, 0.13);
  border-radius: 18px;
  background:
    radial-gradient(circle at 92% 8%, rgba(214, 164, 67, 0.17), transparent 34%),
    linear-gradient(140deg, rgba(15, 107, 104, 0.08), rgba(255, 255, 255, 0.55));
}

.senior-learning-module-hero {
  display: grid;
  grid-template-columns: minmax(180px, 0.68fr) minmax(0, 1.32fr);
  grid-template-rows: auto auto;
  align-items: center;
  column-gap: 24px;
  padding: 17px 22px;
  border-radius: 14px;
}

.senior-learning-module-hero.is-assessment {
  background:
    radial-gradient(circle at 90% 10%, rgba(15, 107, 104, 0.14), transparent 38%),
    linear-gradient(140deg, rgba(214, 164, 67, 0.1), rgba(255, 255, 255, 0.62));
}

.senior-learning-module-hero.is-pending {
  background: linear-gradient(140deg, rgba(160, 107, 38, 0.08), rgba(255, 255, 255, 0.55));
}

.senior-learning-kicker,
.senior-learning-section-heading > p,
.senior-learning-example-heading p,
.senior-learning-summary > p {
  margin: 0 0 8px;
  color: var(--senior-accent);
  font-size: 0.72rem;
  font-weight: 850;
  letter-spacing: 0.12em;
}

.senior-learning-hero h2,
.senior-learning-module-hero h2 {
  margin: 0;
  color: var(--senior-ink);
  font-family: "Songti SC", "Noto Serif SC", "STSong", serif;
  font-size: clamp(1.75rem, 4vw, 2.7rem);
  line-height: 1.18;
}

.senior-learning-module-hero h2 {
  grid-column: 1;
  grid-row: 2;
  font-size: clamp(1.4rem, 2.4vw, 1.85rem);
}

.senior-learning-intro,
.senior-learning-module-hero > p:last-child {
  max-width: 760px;
  margin-top: 18px;
  color: #435459;
  font-size: 0.98rem;
  line-height: 1.9;
}

.senior-learning-module-hero .senior-learning-kicker {
  grid-column: 1;
  grid-row: 1;
  margin-bottom: 4px;
}

.senior-learning-module-hero > p:last-child {
  grid-column: 2;
  grid-row: 1 / span 2;
  margin: 0;
  padding-left: 22px;
  border-left: 1px solid rgba(15, 107, 104, 0.14);
  font-size: 0.88rem;
  line-height: 1.7;
}

.senior-learning-intro p {
  margin: 0.45em 0;
}

.senior-learning-section {
  display: grid;
  gap: 15px;
}

.senior-learning-section-heading h2 {
  margin: 0;
  color: var(--senior-ink);
  font-family: "Songti SC", "Noto Serif SC", "STSong", serif;
  font-size: 1.35rem;
}

.senior-learning-map-shell {
  overflow: hidden;
  border: 1px solid rgba(15, 54, 58, 0.1);
  border-radius: 18px;
  background:
    linear-gradient(rgba(15, 107, 104, 0.028) 1px, transparent 1px),
    linear-gradient(90deg, rgba(15, 107, 104, 0.028) 1px, transparent 1px),
    rgba(255, 255, 255, 0.48);
  background-size: 32px 32px;
}

.senior-learning-map-svg {
  display: block;
  width: 100%;
  height: auto;
  min-height: 390px;
}

.senior-learning-map-svg .map-line {
  fill: none;
  stroke: currentColor;
  stroke-width: 5;
  stroke-linecap: round;
  opacity: 0.72;
}

.senior-learning-map-svg .map-tree.is-coral {
  color: #dc8c75;
}

.senior-learning-map-svg .map-tree.is-blue {
  color: #5d8fc0;
}

.senior-learning-map-svg .map-tree.is-gold {
  color: #d4a339;
}

.senior-learning-map-svg .map-tree.is-green {
  color: #559e83;
}

.senior-learning-map-svg .map-root rect {
  fill: #fffaf1;
  stroke: #0f6b68;
  stroke-width: 4;
}

.senior-learning-map-svg text {
  fill: #15363a;
  font-family: "Songti SC", "Noto Serif SC", "STSong", serif;
  font-size: 24px;
  font-weight: 750;
}

.senior-learning-map-svg .map-root text {
  font-size: 29px;
}

.senior-learning-map-svg .map-twig {
  fill: none;
  stroke: currentColor;
  stroke-width: 3;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.senior-learning-map-svg .map-node rect {
  fill: rgba(255, 255, 255, 0.94);
  stroke: currentColor;
  stroke-width: 2.5;
  transition: fill 140ms ease;
}

.senior-learning-map-svg .map-label {
  font-size: 20px;
}

.senior-learning-map-svg .map-leaf {
  font-size: 18px;
  font-weight: 650;
}

.senior-learning-map-svg .map-note {
  font-size: 12px;
  font-weight: 560;
}

.senior-learning-map-svg .map-branch-link:hover .map-node rect,
.senior-learning-map-svg .map-branch-link:focus .map-node rect {
  fill: #fff8e9;
}

.senior-learning-map-svg .map-branch-link:hover .map-twig,
.senior-learning-map-svg .map-branch-link:focus .map-twig {
  stroke-width: 4;
}

.senior-learning-map-mobile {
  display: none;
}

.senior-learning-module-grid,
.senior-learning-knowledge-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.senior-learning-module-card {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 14px;
  min-height: 145px;
  padding: 20px;
  border: 1px solid rgba(15, 54, 58, 0.11);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.52);
  text-decoration: none;
  transition: border-color 140ms ease, transform 140ms ease, box-shadow 140ms ease;
}

.senior-learning-module-card:hover {
  transform: translateY(-2px);
  border-color: rgba(15, 107, 104, 0.38);
  box-shadow: 0 10px 26px rgba(15, 54, 58, 0.08);
}

.senior-learning-module-card.is-pending {
  background: rgba(246, 240, 228, 0.58);
}

.senior-learning-module-index {
  color: rgba(15, 107, 104, 0.48);
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.78rem;
  font-weight: 800;
}

.senior-learning-module-card h3,
.senior-learning-knowledge-card h3,
.senior-learning-example-card h3,
.senior-learning-pending-card h3 {
  margin: 0;
  color: var(--senior-ink);
  font-family: "Songti SC", "Noto Serif SC", "STSong", serif;
}

.senior-learning-module-card p {
  margin: 8px 0 0;
  color: var(--senior-muted);
  font-size: 0.86rem;
  line-height: 1.65;
}

.senior-learning-module-state {
  grid-column: 2;
  align-self: end;
  color: var(--senior-accent);
  font-size: 0.76rem;
  font-weight: 750;
}

.senior-learning-module-card.is-pending .senior-learning-module-state {
  color: #a06b26;
}

.senior-learning-knowledge-card {
  position: relative;
  min-height: 170px;
  padding: 22px;
  overflow: hidden;
  border: 1px solid rgba(15, 54, 58, 0.1);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.58);
}

.senior-learning-knowledge-card > span {
  position: absolute;
  top: 10px;
  right: 14px;
  color: rgba(15, 107, 104, 0.12);
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 2rem;
  font-weight: 850;
}

.senior-learning-knowledge-card h3 {
  margin-bottom: 12px;
  font-size: 1.05rem;
}

.senior-learning-knowledge-card p {
  margin: 0.45em 0;
  color: #435459;
  font-size: 0.9rem;
  line-height: 1.72;
}

.senior-learning-knowledge-groups {
  display: grid;
  gap: 16px;
}

.senior-learning-knowledge-group {
  display: grid;
  grid-template-columns: 180px minmax(0, 1fr);
  gap: 22px;
  padding: 22px;
  border: 1px solid rgba(15, 54, 58, 0.1);
  border-radius: 15px;
  background: rgba(255, 255, 255, 0.52);
  scroll-margin-top: 24px;
}

.senior-learning-knowledge-group.is-property {
  background: linear-gradient(135deg, rgba(15, 107, 104, 0.065), rgba(255, 255, 255, 0.5));
}

.senior-learning-knowledge-group-heading {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding-right: 18px;
  border-right: 1px solid rgba(15, 107, 104, 0.14);
}

.senior-learning-knowledge-group-heading > span {
  color: rgba(15, 107, 104, 0.38);
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.75rem;
  font-weight: 850;
}

.senior-learning-knowledge-group-heading p {
  margin: 0 0 5px;
  color: var(--senior-accent);
  font-size: 0.69rem;
  font-weight: 800;
  letter-spacing: 0.08em;
}

.senior-learning-knowledge-group-heading h3 {
  margin: 0;
  color: var(--senior-ink);
  font-family: "Songti SC", "Noto Serif SC", "STSong", serif;
  font-size: 1.08rem;
  line-height: 1.45;
}

.senior-learning-exercise-anchor {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  margin-top: 12px;
  padding: 5px 9px;
  border: 1px solid rgba(15, 107, 104, 0.18);
  border-radius: 999px;
  background: rgba(15, 107, 104, 0.045);
  color: var(--senior-accent);
  font-size: 0.69rem;
  font-weight: 700;
  line-height: 1.45;
  text-decoration: none;
  transition: border-color 160ms ease, background 160ms ease, transform 160ms ease;
}

.senior-learning-exercise-anchor strong {
  font-size: 0.72rem;
  font-weight: 850;
}

.senior-learning-exercise-anchor:hover,
.senior-learning-exercise-anchor:focus-visible {
  border-color: rgba(15, 107, 104, 0.36);
  background: rgba(15, 107, 104, 0.09);
  text-decoration: none;
  transform: translateY(-1px);
}

.senior-learning-return-anchor:hover,
.senior-learning-return-anchor:focus-visible {
  text-decoration: underline;
  text-underline-offset: 3px;
}

@media (prefers-reduced-motion: reduce) {
  .senior-learning-exercise-anchor {
    transition: none;
  }
}

.senior-learning-knowledge-items {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}

.senior-learning-knowledge-group.has-1-items .senior-learning-knowledge-items {
  grid-template-columns: minmax(0, 1fr);
}

.senior-learning-knowledge-group.has-2-items .senior-learning-knowledge-items {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.senior-learning-knowledge-item {
  padding: 2px 13px;
  border-left: 3px solid rgba(15, 107, 104, 0.22);
}

.senior-learning-knowledge-group.is-property .senior-learning-knowledge-item {
  border-left-color: rgba(214, 164, 67, 0.54);
}

.senior-learning-knowledge-item h4 {
  margin: 0 0 8px;
  color: var(--senior-ink);
  font-family: "Songti SC", "Noto Serif SC", "STSong", serif;
  font-size: 0.98rem;
}

.senior-learning-knowledge-item p {
  margin: 0;
  color: #435459;
  font-size: 0.85rem;
  line-height: 1.72;
}

.senior-learning-example-list {
  display: grid;
  gap: 0;
}

.senior-learning-exercise-sheet {
  overflow: hidden;
  border: 1px solid rgba(145, 105, 38, 0.15);
  border-top: 3px solid rgba(196, 139, 48, 0.72);
  border-radius: 4px 4px 14px 14px;
  background:
    linear-gradient(rgba(255, 252, 246, 0.88), rgba(250, 245, 235, 0.82)),
    repeating-linear-gradient(0deg, transparent 0 31px, rgba(145, 105, 38, 0.035) 31px 32px);
}

.senior-learning-example-group {
  padding: 20px 22px 0;
  scroll-margin-top: 24px;
}

.senior-learning-example-group + .senior-learning-example-group {
  padding-top: 22px;
  border-top: 1px solid rgba(145, 105, 38, 0.15);
}

.senior-learning-example-group > h3 {
  display: flex;
  align-items: center;
  gap: 9px;
  margin: 0 0 5px;
  color: #4d6535;
  font-family: "Songti SC", "Noto Serif SC", "STSong", serif;
  font-size: 1rem;
}

.senior-learning-example-group > h3::before {
  width: 9px;
  height: 13px;
  border: 2px solid #718b4e;
  border-radius: 1px;
  background: rgba(113, 139, 78, 0.08);
  content: "";
}

.senior-learning-return-anchor {
  display: inline-flex;
  margin: 4px 0 18px;
  color: var(--senior-accent);
  font-size: 0.76rem;
  font-weight: 800;
  text-decoration: none;
}

.senior-learning-example-card {
  padding: 22px;
  border: 1px solid rgba(15, 54, 58, 0.11);
  border-radius: 15px;
  background: rgba(255, 255, 255, 0.58);
}

.senior-learning-example-card.is-pending {
  border-style: dashed;
  background: rgba(246, 240, 228, 0.55);
}

.senior-learning-example {
  position: relative;
  padding: 19px 0 22px;
  border-bottom: 1px dashed rgba(145, 105, 38, 0.2);
}

.senior-learning-example:first-child {
  padding-top: 13px;
}

.senior-learning-example:last-child {
  border-bottom: 0;
}

.senior-learning-compact-example {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 14px;
  padding: 14px 0;
  border-bottom: 1px dashed rgba(145, 105, 38, 0.2);
}

.senior-learning-compact-example > span {
  padding: 3px 8px;
  border-radius: 999px;
  background: rgba(113, 139, 78, 0.1);
  color: #58703c;
  font-size: 0.69rem;
  font-weight: 850;
  white-space: nowrap;
}

.senior-learning-compact-example h4,
.senior-learning-compact-example p {
  margin: 0;
}

.senior-learning-compact-example h4 {
  color: var(--senior-ink);
  font-size: 0.9rem;
}

.senior-learning-compact-example p {
  display: -webkit-box;
  overflow: hidden;
  margin-top: 4px;
  color: #58686b;
  font-size: 0.78rem;
  line-height: 1.5;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
}

.senior-learning-compact-example a {
  color: var(--senior-accent);
  font-size: 0.76rem;
  font-weight: 800;
  white-space: nowrap;
}

.set-figure {
  width: min(100%, 560px);
  margin: 14px auto;
  text-align: center;
}

.set-figure svg {
  display: block;
  width: 100%;
  height: auto;
}

.set-figure-universe,
.set-figure-set {
  fill: none;
  stroke: #173e43;
  stroke-width: 2.2;
}

.set-figure-shade {
  fill: rgba(15, 107, 104, 0.24);
  stroke: none;
}

.set-figure text {
  fill: #173e43;
  font-family: "Songti SC", "Noto Serif SC", serif;
  font-size: 19px;
}

.set-figure figcaption {
  margin-top: 5px;
  color: #667578;
  font-size: 0.75rem;
}

.senior-learning-knowledge-visual {
  grid-column: 1 / -1;
  margin-top: 4px;
}

.senior-learning-problem-figure {
  margin-top: 12px;
}

.senior-learning-example-title-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 18px;
}

.senior-learning-example-index {
  flex: 0 0 auto;
  padding: 3px 8px;
  border-radius: 999px;
  background: rgba(113, 139, 78, 0.1);
  color: #58703c;
  font-size: 0.69rem;
  font-weight: 850;
  letter-spacing: 0.04em;
}

.senior-learning-hint {
  position: relative;
  flex: 0 0 auto;
}

.senior-learning-hint-button {
  display: grid;
  place-items: center;
  width: 28px;
  height: 28px;
  padding: 0;
  border: 1px solid rgba(15, 107, 104, 0.24);
  border-radius: 50%;
  background: rgba(15, 107, 104, 0.06);
  color: var(--senior-accent);
  cursor: pointer;
  font: inherit;
  font-size: 0.78rem;
  font-weight: 850;
}

.senior-learning-hint-popover {
  position: absolute;
  z-index: 5;
  top: 36px;
  right: 0;
  display: none;
  width: min(330px, 76vw);
  padding: 13px 15px;
  border: 1px solid rgba(15, 107, 104, 0.16);
  border-radius: 11px;
  background: #fffdf8;
  box-shadow: 0 12px 30px rgba(15, 54, 58, 0.14);
}

.senior-learning-hint:hover .senior-learning-hint-popover,
.senior-learning-hint-button[aria-expanded="true"] + .senior-learning-hint-popover,
.senior-learning-hint.is-open .senior-learning-hint-popover {
  display: block;
}

.senior-learning-hint-popover p {
  margin: 0;
  color: #435459;
  font-size: 0.78rem;
  line-height: 1.65;
}

.senior-learning-hint-popover p + p {
  margin-top: 8px;
  padding-top: 8px;
  border-top: 1px solid rgba(15, 54, 58, 0.08);
}

.senior-learning-hint-popover strong {
  display: block;
  color: var(--senior-accent);
  font-size: 0.67rem;
  letter-spacing: 0.05em;
}

.senior-learning-example-problem {
  margin-top: 16px;
  color: #152f34;
}

.senior-learning-example .senior-learning-solution-link {
  margin-top: 13px;
}

.senior-learning-answer {
  margin-top: 17px;
  padding: 15px 16px;
  border-left: 3px solid rgba(196, 139, 48, 0.64);
  background: rgba(255, 255, 255, 0.58);
  transition: border-color 140ms ease, background 140ms ease;
}

.senior-learning-answer.is-correct {
  border-left-color: #27865f;
  background: rgba(39, 134, 95, 0.06);
}

.senior-learning-answer.is-incorrect {
  border-left-color: #c78532;
  background: rgba(199, 133, 50, 0.055);
}

.senior-learning-answer.is-expression {
  position: relative;
  padding: 13px 16px 15px;
  border: 1px solid rgba(15, 54, 58, 0.09);
  border-left: 3px solid rgba(196, 139, 48, 0.64);
  border-radius: 2px;
  background: rgba(255, 255, 255, 0.82);
}

.senior-learning-answer.is-expression.is-correct,
.senior-learning-answer.is-expression.is-incorrect {
  background: rgba(255, 255, 255, 0.88);
}

.senior-learning-answer.is-multipart {
  padding: 15px 16px 16px;
}

.senior-learning-answer-prefix.is-multipart-prefix {
  display: block;
  margin-bottom: 9px;
  line-height: 1.5;
}

.senior-learning-multipart-list {
  display: grid;
  gap: 0;
  border: 1px solid rgba(15, 54, 58, 0.1);
  border-radius: 10px;
  overflow: hidden;
  background: #fff;
}

.senior-learning-multipart-row {
  display: grid;
  grid-template-columns: minmax(220px, 0.8fr) minmax(280px, 1.2fr) 58px;
  align-items: center;
  gap: 14px;
  min-height: 82px;
  padding: 10px 12px;
  border-bottom: 1px solid rgba(15, 54, 58, 0.08);
  transition: background 140ms ease, box-shadow 140ms ease;
}

.senior-learning-multipart-row:last-child {
  border-bottom: 0;
}

.senior-learning-multipart-row:focus-within {
  background: rgba(15, 107, 104, 0.025);
  box-shadow: inset 3px 0 rgba(15, 107, 104, 0.42);
}

.senior-learning-multipart-row.is-incomplete,
.senior-learning-multipart-row.is-incorrect {
  background: rgba(199, 133, 50, 0.055);
  box-shadow: inset 3px 0 rgba(199, 133, 50, 0.62);
}

.senior-learning-multipart-row.is-correct {
  background: rgba(39, 134, 95, 0.045);
  box-shadow: inset 3px 0 rgba(39, 134, 95, 0.55);
}

.senior-learning-multipart-prompt {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: center;
  gap: 8px;
  color: var(--senior-ink);
  font-family: "Songti SC", "Noto Serif SC", "STSong", serif;
  line-height: 1.65;
}

.senior-learning-multipart-prompt > span:first-child {
  color: #70824b;
  font-size: 0.82rem;
  font-weight: 800;
}

.senior-learning-symbol-note {
  position: relative;
  display: inline-flex;
  margin-left: 5px;
  vertical-align: middle;
}

.senior-learning-symbol-note-button {
  display: inline-grid;
  place-items: center;
  width: 20px;
  height: 20px;
  padding: 0;
  border: 1px solid rgba(15, 107, 104, 0.28);
  border-radius: 50%;
  background: rgba(15, 107, 104, 0.055);
  color: var(--senior-accent);
  cursor: help;
  font: 700 0.68rem/1 Georgia, "Times New Roman", serif;
}

.senior-learning-symbol-note-button:hover,
.senior-learning-symbol-note-button:focus-visible {
  border-color: rgba(15, 107, 104, 0.55);
  background: rgba(15, 107, 104, 0.11);
  outline: 2px solid rgba(15, 107, 104, 0.1);
}

.senior-learning-symbol-note-popover {
  position: absolute;
  z-index: 6;
  left: 50%;
  bottom: calc(100% + 8px);
  width: max-content;
  max-width: min(260px, 72vw);
  padding: 8px 10px;
  border: 1px solid rgba(15, 107, 104, 0.16);
  border-radius: 8px;
  background: #fffdf8;
  box-shadow: 0 10px 24px rgba(15, 54, 58, 0.14);
  color: #435459;
  font: 0.76rem/1.55 system-ui, -apple-system, "PingFang SC", sans-serif;
  opacity: 0;
  pointer-events: none;
  transform: translate(-50%, 4px);
  transition: opacity 120ms ease, transform 120ms ease;
}

.senior-learning-symbol-note:hover .senior-learning-symbol-note-popover,
.senior-learning-symbol-note:focus-within .senior-learning-symbol-note-popover {
  opacity: 1;
  transform: translate(-50%, 0);
}

.senior-learning-multipart-field {
  display: block;
  min-width: 0;
}

.senior-learning-multipart-field textarea {
  display: block;
  width: 100%;
  min-height: 58px;
  box-sizing: border-box;
  padding: 9px 11px;
  border: 1px solid rgba(15, 54, 58, 0.14);
  border-radius: 8px;
  background: rgba(252, 251, 247, 0.72);
  color: var(--senior-ink);
  font: 0.93rem/1.6 "Songti SC", "Noto Serif SC", "STSong", serif;
  resize: vertical;
}

.senior-learning-multipart-field textarea:focus {
  border-color: rgba(15, 107, 104, 0.5);
  background: #fff;
  outline: 2px solid rgba(15, 107, 104, 0.1);
}

.senior-learning-multipart-symbols {
  display: flex;
  justify-content: flex-end;
  margin-top: 10px;
}

.senior-learning-part-feedback {
  margin: 0;
  color: #8a6732;
  font-size: 0.72rem;
  text-align: center;
}

.senior-learning-multipart-row.is-correct .senior-learning-part-feedback {
  color: #257151;
}

.senior-learning-inline-blank {
  position: relative;
  display: inline-grid;
  place-items: center;
  width: 2.05em;
  min-width: 2.05em;
  height: 1.45em;
  margin: 0 0.12em;
  padding: 0;
  border: 0;
  border-bottom: 1.5px solid rgba(15, 54, 58, 0.62);
  border-radius: 0;
  background: transparent;
  color: var(--senior-accent);
  cursor: pointer;
  font: 1.04em Georgia, "Times New Roman", serif;
  line-height: 1;
  vertical-align: -0.15em;
}

.senior-learning-inline-blank:hover,
.senior-learning-inline-blank.is-active,
.senior-learning-inline-blank:focus-visible {
  border-bottom-color: var(--senior-accent);
  background: rgba(15, 107, 104, 0.055);
  outline: 2px solid rgba(15, 107, 104, 0.12);
  outline-offset: 2px;
}

.senior-learning-answer.is-inline-relation {
  padding: 11px 14px 13px;
  border: 1px solid rgba(15, 54, 58, 0.09);
  border-left: 3px solid rgba(196, 139, 48, 0.64);
  border-radius: 2px;
  background: rgba(255, 255, 255, 0.82);
}

.senior-learning-relation-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.senior-learning-relation-toolbar > span {
  color: #536469;
  font-size: 0.8rem;
}

.senior-learning-relation-options {
  display: flex;
  gap: 7px;
}

.senior-learning-relation-options button {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  min-height: 36px;
  padding: 6px 11px;
  border: 1px solid rgba(15, 107, 104, 0.2);
  border-radius: 8px;
  background: #fffdf8;
  color: var(--senior-ink);
  cursor: pointer;
  font: inherit;
  font-size: 0.78rem;
}

.senior-learning-relation-options button:hover,
.senior-learning-relation-options button:focus-visible {
  border-color: rgba(15, 107, 104, 0.52);
  background: rgba(15, 107, 104, 0.07);
  outline: 2px solid rgba(15, 107, 104, 0.1);
}

.senior-learning-relation-glyph {
  color: var(--senior-accent);
  font: 1.18rem Georgia, "Times New Roman", serif;
}

.senior-learning-answer-line {
  display: flex;
  align-items: flex-start;
  gap: 7px;
  min-height: 88px;
  background: transparent;
}

.senior-learning-answer-line:focus-within {
  background: rgba(15, 107, 104, 0.025);
}

.senior-learning-answer-prefix {
  flex: 0 0 auto;
  color: var(--senior-ink);
  font-family: "Songti SC", "Noto Serif SC", "STSong", serif;
  font-size: 1rem;
  line-height: 42px;
}

.senior-learning-choice-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
}

.senior-learning-choice {
  display: grid;
  grid-template-columns: 25px minmax(0, 1fr);
  gap: 7px;
  align-items: center;
  min-height: 46px;
  padding: 10px 12px;
  border: 1px solid rgba(15, 54, 58, 0.11);
  border-radius: 9px;
  background: rgba(255, 255, 255, 0.66);
  color: #23383d;
  cursor: pointer;
  font: inherit;
  text-align: left;
}

.senior-learning-choice > span:first-child {
  color: var(--senior-accent);
  font-weight: 800;
}

.senior-learning-choice:hover,
.senior-learning-choice.is-selected {
  border-color: rgba(15, 107, 104, 0.46);
  background: rgba(15, 107, 104, 0.08);
}

.senior-learning-answer-label {
  margin: 0 0 11px;
  color: #435459;
  font-size: 0.83rem;
}

.senior-learning-expression-answer {
  display: block;
  flex: 1 1 auto;
  min-width: 0;
}

.senior-learning-expression-answer textarea {
  width: 100%;
  min-height: 86px;
  box-sizing: border-box;
  padding: 0 3px;
  border: 0;
  border-radius: 0;
  background: transparent;
  color: var(--senior-ink);
  font: 1.02rem "Songti SC", "Noto Serif SC", "STSong", serif;
  line-height: 43px;
  resize: vertical;
}

.senior-learning-expression-answer textarea:focus {
  outline: 0;
}

.senior-learning-symbol-toggle {
  display: grid;
  place-items: center;
  flex: 0 0 auto;
  width: 31px;
  height: 31px;
  padding: 0;
  border: 1px solid rgba(15, 107, 104, 0.2);
  border-radius: 50%;
  background: rgba(15, 107, 104, 0.055);
  color: var(--senior-accent);
  cursor: pointer;
  font: 0.9rem Georgia, serif;
  margin-top: 6px;
}

.senior-learning-symbol-toggle:hover,
.senior-learning-symbol-toggle[aria-expanded="true"] {
  border-color: rgba(15, 107, 104, 0.5);
  background: rgba(15, 107, 104, 0.1);
}

.senior-learning-repeated-answer {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.senior-learning-repeated-answer label,
.senior-learning-integer-answer {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--senior-ink);
  font-family: "Songti SC", "Noto Serif SC", "STSong", serif;
}

.senior-learning-repeated-answer input,
.senior-learning-integer-answer input {
  width: 82px;
  min-height: 38px;
  padding: 7px 9px;
  border: 1px solid rgba(15, 54, 58, 0.2);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.9);
  color: var(--senior-ink);
  font: 0.96rem ui-monospace, SFMono-Regular, Menlo, monospace;
  text-align: center;
}

.senior-learning-repeated-answer input:focus,
.senior-learning-integer-answer input:focus {
  border-color: var(--senior-accent);
  outline: 2px solid rgba(15, 107, 104, 0.12);
}

.senior-learning-answer-preview {
  min-width: 28px;
  color: var(--senior-accent);
  font-size: 0.82rem;
}

.senior-learning-math-keyboard {
  display: none;
  flex-wrap: wrap;
  gap: 5px;
  margin-top: 9px;
  padding: 11px;
  border: 1px solid rgba(15, 107, 104, 0.16);
  border-radius: 10px;
  background: #fffdf8;
  box-shadow: 0 12px 28px rgba(15, 54, 58, 0.14);
}

.senior-learning-math-keyboard.is-visible {
  display: flex;
}

.senior-learning-math-keyboard button {
  min-width: 34px;
  min-height: 34px;
  padding: 5px 9px;
  border: 1px solid rgba(15, 54, 58, 0.13);
  border-radius: 7px;
  background: rgba(255, 255, 255, 0.8);
  color: var(--senior-ink);
  cursor: pointer;
  font: inherit;
  font-size: 0.78rem;
}

.senior-learning-math-keyboard button:hover {
  border-color: rgba(15, 107, 104, 0.42);
  color: var(--senior-accent);
}

.senior-learning-answer-actions {
  display: flex;
  align-items: center;
  gap: 13px;
  margin-top: 13px;
}

.senior-learning-submit {
  flex: 0 0 auto;
  padding: 8px 15px;
  border: 0;
  border-radius: 999px;
  background: var(--senior-accent);
  color: #fff;
  cursor: pointer;
  font: inherit;
  font-size: 0.76rem;
  font-weight: 800;
}

.senior-learning-answer-feedback {
  margin: 0;
  color: #6c5b43;
  font-size: 0.78rem;
  line-height: 1.5;
}

.senior-learning-answer.is-correct .senior-learning-answer-feedback {
  color: #257151;
}

.senior-learning-example-heading {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
}

.senior-learning-example-heading h3 {
  font-size: 1.04rem;
  line-height: 1.45;
}

.senior-learning-question-number {
  display: grid;
  place-items: center;
  flex: 0 0 auto;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  background: var(--senior-accent-soft);
  color: var(--senior-accent);
  font-size: 0.82rem;
  font-weight: 800;
}

.senior-learning-example-summary,
.senior-learning-pending-note {
  margin: 10px 0 0;
  color: var(--senior-muted);
  font-size: 0.84rem;
  line-height: 1.65;
}

.senior-learning-problem {
  margin-top: 16px;
  padding: 17px 18px;
  border: 1px solid rgba(15, 54, 58, 0.08);
  border-radius: 11px;
  background: rgba(255, 252, 246, 0.72);
}

.senior-learning-problem-line {
  color: #152f34;
  font-family: "Songti SC", "Noto Serif SC", "STSong", serif;
  font-size: 0.97rem;
  line-height: 1.82;
}

.senior-learning-options {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px 22px;
  margin-top: 10px;
}

.senior-learning-options.is-stacked {
  grid-template-columns: minmax(0, 1fr);
}

.senior-learning-option {
  display: grid;
  grid-template-columns: 22px minmax(0, 1fr);
  gap: 4px;
  color: #23383d;
  font-family: "Songti SC", "Noto Serif SC", "STSong", serif;
  font-size: 0.9rem;
  line-height: 1.65;
}

.senior-learning-solution-link,
.senior-learning-back-link {
  display: inline-flex;
  margin-top: 15px;
  color: var(--senior-accent) !important;
  font-size: 0.82rem;
  font-weight: 800;
  text-decoration: none;
}

.senior-learning-summary,
.senior-learning-pending-card {
  padding: 22px 24px;
  border-left: 4px solid var(--senior-accent);
  border-radius: 0 13px 13px 0;
  background: rgba(15, 107, 104, 0.07);
}

.senior-learning-summary div,
.senior-learning-pending-card p {
  color: #354b50;
  font-size: 0.9rem;
  line-height: 1.75;
}

.senior-learning-pending-card {
  border-left-color: #c58b35;
  background: rgba(197, 139, 53, 0.07);
}

.senior-learning-known-points {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 14px 0;
}

.senior-learning-known-points span {
  padding: 6px 10px;
  border: 1px solid rgba(160, 107, 38, 0.22);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.52);
  color: #7a541f;
  font-size: 0.8rem;
}

.senior-learning-view .inline-math {
  display: inline;
  white-space: nowrap;
}

.senior-learning-view .math-notin,
.senior-library-worksheet .math-notin {
  display: inline-flex;
  width: 0.92em;
  height: 1em;
  vertical-align: -0.12em;
}

.senior-learning-view .math-notin svg,
.senior-library-worksheet .math-notin svg {
  width: 100%;
  height: 100%;
  overflow: visible;
}

.senior-learning-view .math-notin path,
.senior-library-worksheet .math-notin path {
  fill: none;
  stroke: currentColor;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: 1.55;
}

.senior-learning-view .math-blackboard,
.senior-library-worksheet .math-blackboard,
.senior-learning-math-keyboard .math-blackboard {
  font-family: "STIX Two Math", "Cambria Math", "STIXGeneral", "Noto Sans Math", serif;
  font-style: normal;
  font-weight: 400;
  letter-spacing: 0;
}

.senior-learning-view .math-fraction {
  display: inline-grid;
  grid-template-rows: auto auto;
  min-width: 1.15em;
  margin: 0 0.08em;
  vertical-align: middle;
  line-height: 1;
  text-align: center;
}

.senior-learning-view .math-numerator {
  padding: 0 0.12em 0.06em;
  border-bottom: 1.2px solid currentColor;
}

.senior-learning-view .math-denominator {
  padding: 0.05em 0.12em 0;
}

.senior-learning-view .math-radical {
  display: inline-flex;
  align-items: flex-start;
  vertical-align: -0.12em;
}

.senior-learning-view .math-radical-symbol {
  margin-right: -0.05em;
  font-size: 1.18em;
}

.senior-learning-view .math-radicand {
  margin-top: 0.06em;
  padding: 0 0.08em 0 0.1em;
  border-top: 1.2px solid currentColor;
}

.senior-library-page-button {
  display: grid;
  place-items: center;
  min-width: 34px;
  height: 34px;
  padding: 0 9px;
  border: 1px solid var(--senior-line);
  border-radius: 5px;
  background: rgba(255, 255, 255, 0.58);
  color: var(--senior-muted);
  cursor: pointer;
}

.senior-library-page-button.is-active {
  border-color: var(--senior-accent);
  background: var(--senior-accent);
  color: #fff;
}

.senior-library-page-button:disabled {
  cursor: default;
  opacity: 0.38;
}

@media (max-width: 1040px) {
  .senior-library-shell {
    width: min(100% - 56px, 1180px);
  }

  .senior-library-shell {
    grid-template-columns: 184px minmax(0, 1fr);
  }

  .senior-library-content {
    padding: 14px;
  }

  .senior-library-card {
    grid-template-columns: 126px minmax(0, 1fr);
  }
}

@media (max-width: 820px) {
  .senior-library-shell {
    grid-template-columns: 1fr;
  }

  .senior-library-sidebar {
    border: 1px solid rgba(15, 54, 58, 0.1);
  }

  .senior-library-sidebar-inner {
    position: static;
    padding: 12px;
  }

  .senior-library-sidebar-label {
    display: none;
  }

  .senior-library-chapters {
    display: flex;
    gap: 5px;
    max-width: 100%;
    overflow-x: auto;
    padding-bottom: 2px;
  }

  .senior-library-chapter-group {
    flex: 0 0 auto;
  }

  .senior-library-chapter {
    flex: 0 0 auto;
    grid-template-columns: auto auto;
    min-height: 36px;
    padding: 5px 10px;
  }

  .senior-library-subchapters {
    margin: 2px 0 0 18px;
  }

  .senior-library-content {
    padding: 14px;
  }
}

@media (max-width: 760px) {
  .senior-library-shell {
    width: min(100% - 28px, 1180px);
    gap: 10px;
    padding: 4px 0 28px;
  }
}

@media (max-width: 720px) {
  .senior-learning-choice-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .senior-learning-compact-example {
    grid-template-columns: auto minmax(0, 1fr);
  }

  .senior-learning-compact-example a {
    grid-column: 2;
  }
  .senior-library-toolbar {
    align-items: flex-start;
    flex-direction: column;
    gap: 12px;
  }

  .senior-library-filters {
    width: 100%;
    overflow-x: auto;
  }

  .senior-library-filters label {
    flex: 0 0 auto;
  }

  .senior-library-grid {
    grid-template-columns: 1fr;
  }

  .senior-worksheet-figures {
    grid-template-columns: minmax(0, 1fr);
  }

  .senior-learning-map-svg {
    display: none;
  }

  .senior-learning-map-mobile {
    display: grid;
    gap: 10px;
    padding: 14px;
  }

  .senior-learning-map-mobile a {
    display: grid;
    gap: 5px;
    padding: 15px;
    border: 1px solid rgba(15, 107, 104, 0.14);
    border-radius: 12px;
    background: rgba(255, 255, 255, 0.64);
    text-decoration: none;
  }

  .senior-learning-map-mobile strong {
    color: var(--senior-ink);
    font-family: "Songti SC", "Noto Serif SC", "STSong", serif;
  }

  .senior-learning-map-mobile span {
    color: var(--senior-muted);
    font-size: 0.8rem;
    line-height: 1.55;
  }

  .senior-learning-module-grid,
  .senior-learning-knowledge-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .senior-learning-knowledge-group {
    grid-template-columns: minmax(0, 1fr);
    gap: 16px;
  }

  .senior-learning-knowledge-group-heading {
    padding-right: 0;
    padding-bottom: 13px;
    border-right: 0;
    border-bottom: 1px solid rgba(15, 107, 104, 0.14);
  }

  .senior-learning-multipart-row {
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 8px 10px;
    padding: 12px;
  }

  .senior-learning-multipart-prompt {
    grid-column: 1 / -1;
  }

  .senior-learning-multipart-field {
    grid-column: 1;
  }

  .senior-learning-part-feedback {
    grid-column: 2;
    min-width: 52px;
  }
}

@media (max-width: 480px) {
  .senior-library-card {
    grid-template-columns: 112px minmax(0, 1fr);
    min-height: 170px;
  }

  .senior-library-thumbnail img {
    min-height: 170px;
  }

  .senior-library-card-body {
    padding: 12px;
  }

  .senior-library-content {
    padding: 12px;
  }

  .senior-library-collection-entry {
    min-height: 92px;
    padding: 14px;
  }

  .senior-library-collection-action {
    display: none;
  }

  .senior-worksheet-problem {
    grid-template-columns: 25px minmax(0, 1fr);
    padding: 15px 0 16px;
  }

  .senior-worksheet-line {
    font-size: 0.9rem;
  }

  .senior-learning-hero,
  .senior-learning-module-hero {
    padding: 23px 20px;
    border-radius: 14px;
  }

  .senior-learning-module-hero {
    display: block;
    padding: 15px 17px;
  }

  .senior-learning-module-hero > p:last-child {
    margin-top: 8px;
    padding-left: 0;
    border-left: 0;
    font-size: 0.82rem;
  }

  .senior-learning-topic {
    gap: 20px;
  }

  .senior-learning-module-card,
  .senior-learning-example-card,
  .senior-learning-knowledge-card {
    padding: 17px;
  }

  .senior-learning-options {
    grid-template-columns: minmax(0, 1fr);
  }

  .senior-learning-problem {
    padding: 14px;
  }

  .senior-learning-knowledge-items,
  .senior-learning-choice-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .senior-learning-example-group {
    padding-right: 15px;
    padding-left: 15px;
  }

  .senior-learning-answer-actions {
    align-items: flex-start;
    flex-direction: column;
  }

  .senior-learning-relation-toolbar {
    align-items: flex-start;
    flex-direction: column;
  }
}

@media (prefers-reduced-motion: reduce) {
  .senior-library-card,
  .senior-library-chapter {
    transition: none;
  }
}