.research-timeline {
  --rt-ink: var(--ink, #171717);
  --rt-muted: var(--muted, #555);
  --rt-line: var(--line, #d8d8d8);
  --rt-soft: var(--soft, #f6f7f8);
  --rt-blue: var(--blue, #295f9b);
  --rt-rose: var(--rose, #9a3856);
  --rt-gold: var(--gold, #a06b13);
  --rt-green: var(--green, #13795b);
  --rt-ink-soft: #f2f2f2;
  --rt-blue-soft: #f1f6fb;
  --rt-rose-soft: #fbf1f4;
  --rt-gold-soft: #fff7e8;
  --rt-green-soft: #eef8f3;
  margin: 10px 0 4px;
}

.rt-heading {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 7px;
}

.rt-heading > div:first-child {
  flex: 0 0 auto;
}

.rt-title {
  margin: 0;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 24px;
  line-height: 1.05;
  font-weight: 500;
  letter-spacing: 0;
  white-space: nowrap;
}

.rt-subtitle {
  margin: 3px 0 0;
  color: var(--rt-muted);
  font-size: 13px;
  font-weight: 600;
}

.rt-legend {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 5px 10px;
  color: var(--rt-muted);
  font-size: 10.5px;
  font-weight: 700;
}

.rt-legend-item {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  white-space: nowrap;
}

.rt-swatch {
  width: 10px;
  height: 10px;
  border-radius: 3px;
  border: 2px solid currentColor;
  background: #fff;
}

.rt-swatch.transfer {
  color: var(--rt-blue);
  background: var(--rt-blue-soft);
}

.rt-swatch.human,
.rt-swatch.vision {
  color: var(--rt-rose);
  background: var(--rt-rose-soft);
}

.rt-swatch.generative {
  color: var(--rt-gold);
  background: var(--rt-gold-soft);
}

.rt-swatch.agent {
  color: var(--rt-green);
  background: var(--rt-green-soft);
}

.rt-swatch.perception {
  color: var(--rt-ink);
  background: var(--rt-ink-soft);
}

.rt-years {
  display: grid;
  gap: 5px;
}

.rt-row {
  display: grid;
  grid-template-columns: 52px 1fr;
  gap: 7px;
  align-items: center;
  padding: 5px 7px;
  border: 1px solid var(--rt-line);
  border-radius: 6px;
  background: #fff;
}

.rt-row:nth-child(odd) {
  background: var(--rt-soft);
}

.rt-year {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 22px;
  border-radius: 4px;
  background: var(--rt-ink);
  color: #fff;
  font-size: 12px;
  font-weight: 800;
  line-height: 1;
}

.rt-cards {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 5px 7px;
}

.rt-card {
  position: relative;
  display: block;
  min-height: 36px;
  padding: 8px 6px 5px;
  border: 1px solid var(--rt-line);
  border-radius: 5px;
  color: var(--rt-ink);
  text-decoration: none;
  transition: border-color 140ms ease, box-shadow 140ms ease, transform 140ms ease;
}

.rt-card:hover {
  text-decoration: none;
  border-color: #b8b8b8;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.08);
  transform: translateY(-1px);
}

.rt-card:focus-visible {
  outline: 2px solid var(--link, #1756a9);
  outline-offset: 2px;
}

.rt-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  border-radius: 5px 5px 0 0;
  background: currentColor;
}

.rt-card.transfer {
  color: var(--rt-blue);
  background: var(--rt-blue-soft);
}

.rt-card.human,
.rt-card.vision {
  color: var(--rt-rose);
  background: var(--rt-rose-soft);
}

.rt-card.generative {
  color: var(--rt-gold);
  background: var(--rt-gold-soft);
}

.rt-card.agent {
  color: var(--rt-green);
  background: var(--rt-green-soft);
}

.rt-card.perception {
  color: var(--rt-ink);
  background: var(--rt-ink-soft);
}

.rt-card-main,
.rt-card-title {
  display: block;
  color: var(--rt-ink);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.rt-card-main {
  font-size: 11px;
  font-weight: 800;
  line-height: 1.1;
}

.rt-card-title {
  margin-top: 1px;
  font-size: 11px;
  font-weight: 700;
  line-height: 1.15;
}

.rt-ongoing {
  display: grid;
  grid-template-columns: 106px 1fr;
  gap: 8px;
  align-items: center;
  margin: 0 0 7px;
  padding: 8px 10px;
  border: 1px solid var(--rt-line);
  border-top: 4px solid var(--rt-green);
  border-radius: 6px;
  background: var(--rt-green-soft);
}

.rt-ongoing strong {
  color: var(--rt-ink);
}

.rt-ongoing span {
  color: var(--rt-muted);
  font-size: 11px;
  font-weight: 650;
}

.rt-note {
  margin: 10px 0 0;
  color: var(--rt-muted);
  font-size: 13px;
}

@media (max-width: 840px) {
  .rt-heading {
    display: block;
  }

  .rt-legend {
    justify-content: flex-start;
    margin-top: 7px;
  }

  .rt-cards {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (max-width: 560px) {
  .rt-row,
  .rt-ongoing {
    grid-template-columns: 1fr;
  }

  .rt-cards {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .rt-year {
    width: 58px;
  }
}