/* ── Research Activity Timeline ── */
.tl-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 24px;
}
.tl-filter-btn {
  padding: 5px 14px;
  border: 1px solid #2980b9;
  border-radius: 20px;
  background: transparent;
  color: #2980b9;
  cursor: pointer;
  font-size: 0.85rem;
  transition: background 0.2s, color 0.2s;
}
.tl-filter-btn.active,
.tl-filter-btn:hover {
  background: #2980b9;
  color: #fff;
}
.tl-container {
  position: relative;
  padding-left: 36px;
}
.tl-container::before {
  content: "";
  position: absolute;
  left: 10px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: #d0d7de;
}
.tl-item {
  position: relative;
  margin-bottom: 28px;
  transition: opacity 0.25s;
}
.tl-item.hidden {
  display: none;
}
.tl-dot {
  position: absolute;
  left: -30px;
  top: 4px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  border: 2px solid #fff;
  box-shadow: 0 0 0 2px currentColor;
}
.tl-card {
  border: 1px solid #e1e4e8;
  border-radius: 6px;
  padding: 14px 18px;
  background: #fff;
}
.tl-meta {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 6px;
  flex-wrap: wrap;
}
.tl-date {
  font-size: 0.78rem;
  color: #6a737d;
}
.tl-badge {
  font-size: 0.72rem;
  font-weight: 600;
  padding: 2px 9px;
  border-radius: 12px;
  color: #fff;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.tl-card h3 {
  margin: 0 0 6px;
  font-size: 1rem;
}
.tl-card p {
  margin: 0;
  font-size: 0.88rem;
  color: #444d56;
}

/* Category colours */
.cat-release  { color: #2ea44f; }
.badge-release  { background: #2ea44f; }
.cat-discovery { color: #6f42c1; }
.badge-discovery { background: #6f42c1; }
.cat-update   { color: #2980b9; }
.badge-update   { background: #2980b9; }
.cat-community { color: #e36209; }
.badge-community { background: #e36209; }