.world-learning-section {
  margin-top: 1rem;
  padding: clamp(1.4rem, 3vw, 2.5rem);
  background: #eaf1ee;
  border: 1px solid rgba(47, 118, 109, 0.2);
  border-radius: 1.35rem;
  box-shadow: var(--shadow);
}

.world-learning-heading {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: end;
  gap: 1.5rem;
}

.world-learning-heading h2 {
  max-width: 760px;
  margin: 0.55rem 0 0;
  color: var(--text-heading);
  font-family: var(--font-display);
  font-size: clamp(1.45rem, 3vw, 2.35rem);
  font-weight: 600;
  letter-spacing: -0.025em;
  line-height: 1.35;
}

.world-learning-heading > div:first-child > p:last-child {
  max-width: 760px;
  margin: 0.75rem 0 0;
  color: var(--text-muted);
  font-size: 0.72rem;
  line-height: 1.75;
}

.world-learning-progress {
  display: flex;
  align-items: baseline;
  gap: 0.45rem;
  min-width: 112px;
  padding: 0.65rem 0.85rem;
  color: var(--on-brand);
  background: var(--surface-brand-strong);
  border-radius: 0.75rem;
}

.world-learning-progress strong {
  font-family: var(--font-display);
  font-size: 1.7rem;
  font-weight: 600;
  line-height: 1;
}

.world-learning-progress span {
  color: rgba(255, 255, 255, 0.58);
  font-size: 0.58rem;
  font-weight: 900;
  letter-spacing: 0.04em;
}

.world-learning-toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-top: 1.4rem;
  padding-top: 1rem;
  border-top: 1px solid rgba(47, 118, 109, 0.2);
}

.world-learning-toolbar button {
  padding: 0.55rem 0.8rem;
  color: var(--text-muted);
  background: rgba(255, 255, 255, 0.6);
  border: 1px solid rgba(47, 118, 109, 0.18);
  border-radius: 999px;
  font-size: 0.66rem;
  font-weight: 900;
}

.world-learning-toolbar button span {
  display: inline-grid;
  min-width: 20px;
  height: 20px;
  margin-left: 0.3rem;
  place-items: center;
  color: var(--text-accent);
  background: var(--surface-card);
  border-radius: 50%;
  font-family: var(--font-display);
}

.world-learning-toolbar button:hover,
.world-learning-toolbar button[aria-pressed="true"] {
  color: var(--on-brand);
  background: var(--mineral);
  border-color: var(--mineral);
}

.world-learning-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  align-items: start;
  gap: 0.75rem;
  margin-top: 1rem;
}

.world-learning-card-shell.is-open {
  grid-column: 1 / -1;
  order: -1;
}

.world-learning-card {
  --world-accent: var(--mineral);
  --world-accent-soft: #dcece7;
  --world-terrain: #2f766d;
  overflow: hidden;
  background: var(--surface-card);
  border: 1px solid rgba(31, 55, 53, 0.14);
  border-bottom: 3px solid var(--world-accent);
  border-radius: 1rem;
  box-shadow: 0 12px 28px rgba(31, 55, 53, 0.06);
}

.world-learning-card--mixed {
  --world-accent: var(--vermilion);
  --world-accent-soft: #f4e2dc;
  --world-terrain: var(--indigo);
}

.world-learning-card--cultural {
  --world-accent: #a8573f;
  --world-accent-soft: #f3e4dc;
  --world-terrain: #78483e;
}

.world-learning-card summary {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 34px;
  min-height: 100%;
  cursor: pointer;
  list-style: none;
}

.world-learning-card summary::-webkit-details-marker {
  display: none;
}

.world-learning-card__terrain {
  position: relative;
  display: block;
  grid-column: 1 / -1;
  height: 76px;
  overflow: hidden;
  background-color: var(--world-terrain);
  background-image:
    repeating-radial-gradient(ellipse at 18% 118%, transparent 0 10px, rgba(255, 255, 255, 0.16) 11px 12px, transparent 13px 22px),
    repeating-radial-gradient(ellipse at 83% -22%, transparent 0 12px, rgba(255, 255, 255, 0.1) 13px 14px, transparent 15px 25px);
}

.world-learning-card__terrain::before,
.world-learning-card__terrain::after {
  position: absolute;
  content: "";
}

.world-learning-card__terrain::before {
  right: 12%;
  bottom: -27px;
  width: 110px;
  height: 68px;
  background: var(--world-accent-soft);
  border-radius: 52% 48% 0 0;
  opacity: 0.18;
  transform: rotate(-8deg);
}

.world-learning-card__terrain::after {
  top: 50%;
  left: 12%;
  width: 74%;
  height: 1px;
  background: rgba(255, 255, 255, 0.46);
  transform: rotate(-5deg);
}

.world-learning-card__terrain i {
  position: absolute;
  z-index: 1;
  top: calc(50% - 4px);
  right: 11%;
  width: 7px;
  height: 7px;
  background: var(--surface-card);
  border: 2px solid var(--world-accent);
  border-radius: 50%;
}

.world-learning-card--cultural .world-learning-card__terrain {
  background-image:
    repeating-linear-gradient(90deg, transparent 0 23px, rgba(255, 255, 255, 0.1) 24px 25px),
    repeating-linear-gradient(0deg, transparent 0 15px, rgba(255, 255, 255, 0.08) 16px 17px),
    linear-gradient(145deg, rgba(255, 255, 255, 0.16), transparent 62%);
}

.world-learning-card--cultural .world-learning-card__terrain::before {
  right: 12%;
  bottom: -1px;
  width: 74px;
  height: 48px;
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.52);
  border-bottom: 0;
  border-radius: 42px 42px 0 0;
  opacity: 1;
  transform: none;
}

.world-learning-card--cultural .world-learning-card__terrain::after {
  top: auto;
  bottom: 17px;
  left: 8%;
  width: 78%;
  background: rgba(255, 255, 255, 0.42);
  transform: none;
}

.world-learning-card--cultural .world-learning-card__terrain i {
  top: 14px;
  right: 18%;
}

.world-learning-card__copy {
  display: grid;
  gap: 0.7rem;
  padding: 1rem 0.4rem 1.1rem 1rem;
}

.world-learning-card__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem;
  color: var(--text-muted);
  font-size: 0.55rem;
  font-weight: 900;
}

.world-learning-card__meta span:not(:last-child)::after {
  margin-left: 0.3rem;
  color: var(--world-accent);
  content: "／";
}

.world-learning-card__copy > strong {
  color: var(--text-heading);
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 600;
  line-height: 1.5;
}

.world-learning-card__lead {
  color: var(--text-muted);
  font-size: 0.66rem;
  line-height: 1.7;
}

.world-learning-keywords {
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem;
}

.world-learning-keywords span {
  padding: 0.25rem 0.42rem;
  color: var(--world-terrain);
  background: var(--world-accent-soft);
  border-radius: 999px;
  font-size: 0.54rem;
  font-weight: 900;
}

.world-learning-card__mark {
  align-self: end;
  display: grid;
  width: 26px;
  height: 26px;
  margin: 0 0.7rem 1rem 0;
  place-items: center;
  color: var(--on-brand);
  background: var(--world-accent);
  border-radius: 50%;
}

.world-learning-card__mark::before {
  content: "+";
  font-size: 0.9rem;
  font-weight: 900;
}

.world-learning-card[open] .world-learning-card__mark::before {
  content: "−";
}

.world-learning-card[open] summary {
  grid-template-columns: minmax(0, 1fr) 42px;
  border-bottom: 1px solid var(--line);
}

.world-learning-card[open] .world-learning-card__terrain {
  height: 96px;
}

.world-learning-card[open] .world-learning-card__copy {
  padding-right: 1rem;
}

.world-learning-card__body {
  padding: clamp(1rem, 2.5vw, 2rem);
}

.world-learning-registration {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
}

.world-learning-registration span {
  padding: 0.35rem 0.55rem;
  color: var(--text-muted);
  background: var(--surface-page);
  border: 1px solid var(--line);
  border-radius: 0.45rem;
  font-size: 0.58rem;
  font-weight: 900;
}

.world-learning-photo {
  overflow: hidden;
  margin: 1rem 0;
  background: var(--surface-tinted);
  border: 1px solid var(--line);
  border-radius: 0.85rem;
}

.world-learning-photo__frame {
  position: relative;
  display: grid;
  aspect-ratio: 16 / 7;
  overflow: hidden;
  place-items: center;
  background:
    radial-gradient(circle at 82% 18%, rgba(255, 255, 255, 0.72), transparent 28%),
    linear-gradient(135deg, var(--paper-blue), #c9dde0);
}

.world-learning-photo__frame::before {
  color: var(--text-muted);
  content: "写真を読み込み中…";
  font-size: 0.62rem;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.world-learning-photo.is-unavailable .world-learning-photo__frame::before {
  content: "写真を読み込めませんでした";
}

.world-learning-photo__frame img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 1;
  transition: opacity 260ms ease;
}

.world-learning-photo.is-loading .world-learning-photo__frame img {
  opacity: 0;
}

.world-learning-photo figcaption {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.7rem 0.85rem;
  background: rgba(248, 251, 251, 0.96);
}

.world-learning-photo__subject {
  display: flex;
  min-width: 0;
  align-items: baseline;
  gap: 0.5rem;
}

.world-learning-photo__subject small {
  flex: 0 0 auto;
  color: var(--world-accent);
  font-size: 0.54rem;
  font-weight: 900;
  letter-spacing: 0.08em;
}

.world-learning-photo__subject strong {
  overflow: hidden;
  color: var(--text-accent);
  font-family: var(--font-display);
  font-size: 0.72rem;
  font-weight: 600;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.world-learning-photo__credit {
  display: flex;
  flex: 0 0 auto;
  align-items: center;
  color: var(--text-muted);
  font-size: 0.54rem;
}

.world-learning-photo__credit a {
  color: inherit;
  text-underline-offset: 0.18rem;
}

.world-learning-photo__credit a:hover,
.world-learning-photo__credit a:focus-visible {
  color: var(--text-accent);
}

.world-learning-recall {
  display: flex;
  align-items: baseline;
  gap: 0.7rem;
  margin: 1rem 0;
  padding: 0.8rem 0;
  color: var(--text-heading);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  font-family: var(--font-display);
  font-size: 0.92rem;
  font-weight: 600;
  line-height: 1.6;
}

.world-learning-recall span {
  flex: 0 0 auto;
  color: var(--world-accent);
  font-family: var(--font-body);
  font-size: 0.56rem;
  font-weight: 900;
  letter-spacing: 0.08em;
}

.world-learning-checkpoints {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.65rem;
}

.world-learning-checkpoints article {
  padding: 0.9rem;
  background: var(--surface-page);
  border-top: 2px solid var(--world-accent);
  border-radius: 0.65rem;
}

.world-learning-checkpoints article > span {
  color: var(--world-accent);
  font-size: 0.54rem;
  font-weight: 900;
  letter-spacing: 0.05em;
}

.world-learning-checkpoints h4 {
  margin: 0.45rem 0 0;
  color: var(--text-heading);
  font-family: var(--font-display);
  font-size: 0.82rem;
  font-weight: 600;
  line-height: 1.5;
}

.world-learning-checkpoints p {
  margin: 0.45rem 0 0;
  color: var(--text-muted);
  font-size: 0.63rem;
  line-height: 1.7;
}

.world-learning-compare,
.world-learning-translation {
  display: grid;
  grid-template-columns: 76px minmax(0, 1fr);
  gap: 0.85rem;
  margin-top: 0.7rem;
  padding: 0.9rem;
  border-radius: 0.65rem;
}

.world-learning-compare {
  background: var(--surface-brand-strong);
}

.world-learning-compare > span,
.world-learning-translation > span {
  color: #9dc6c2;
  font-size: 0.55rem;
  font-weight: 900;
  letter-spacing: 0.07em;
}

.world-learning-compare strong {
  color: var(--on-brand);
  font-family: var(--font-display);
  font-size: 0.76rem;
  font-weight: 600;
}

.world-learning-compare p,
.world-learning-translation p {
  margin: 0.35rem 0 0;
  font-size: 0.63rem;
  line-height: 1.7;
}

.world-learning-compare p {
  color: rgba(255, 255, 255, 0.68);
}

.world-learning-translation {
  color: var(--text-muted);
  background: var(--world-accent-soft);
}

.world-learning-translation > span {
  color: var(--world-terrain);
}

.world-learning-card__footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px dashed var(--line);
}

.world-learning-card__footer > a {
  color: var(--world-terrain);
  font-size: 0.62rem;
  font-weight: 900;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2rem;
}

.world-learning-related {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: flex-end;
  gap: 0.35rem;
}

.world-learning-related > span,
.world-learning-related small {
  color: var(--text-muted);
  font-size: 0.55rem;
  font-weight: 900;
}

.world-learning-related a {
  padding: 0.3rem 0.45rem;
  color: var(--text-accent);
  background: var(--surface-tinted);
  border-radius: 999px;
  font-size: 0.55rem;
  font-weight: 900;
  text-decoration: none;
}

.world-learning-related a:hover {
  color: var(--on-brand);
  background: var(--mineral);
}