/* ===== FILTER TABS ===== */
.filter-tabs {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-bottom: 3rem;
}
.filter-tab {
  padding: 0.375rem 1rem;
  border-radius: 20px;
  font-size: 0.8125rem;
  font-weight: 700;
  cursor: pointer;
  border: 1px solid var(--bg-border);
  color: var(--text-secondary);
  background: var(--bg-card);
  transition: all var(--transition);
}
.filter-tab[aria-pressed="true"] {
  background: var(--accent-purple);
  border-color: var(--accent-purple);
  color: #0f0f1a;
}
.filter-tab:hover:not([aria-pressed="true"]) {
  border-color: var(--accent-purple);
  color: var(--text-primary);
}

/* ===== TIMELINE ===== */
.timeline {
  position: relative;
  padding-left: 3rem;
}
.timeline::before {
  content: '';
  position: absolute;
  left: 18px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(to bottom, var(--accent-purple), var(--accent-coral));
  border-radius: 1px;
}

/* ===== CHECKPOINT CARD ===== */
.checkpoint-card {
  position: relative;
  margin-bottom: 2rem;
  transition: opacity var(--transition);
}
.checkpoint-card.dimmed { opacity: 0.25; }
.checkpoint-dot {
  position: absolute;
  left: -2.5rem;
  top: 0.75rem;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 0.8125rem;
  font-weight: 700;
  z-index: 1;
}
.checkpoint-inner {
  background: var(--bg-card);
  border: 1px solid var(--bg-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  transition: border-color var(--transition), transform var(--transition);
}
.checkpoint-card:not(.dimmed) .checkpoint-inner:hover {
  border-color: var(--accent-purple);
  transform: translateX(4px);
}
.checkpoint-meta {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.5rem;
  flex-wrap: wrap;
}
.checkpoint-week {
  font-size: 0.6875rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
}
.checkpoint-badge {
  font-size: 0.6875rem;
  padding: 2px 8px;
  border-radius: 10px;
  font-weight: 600;
}
.checkpoint-title {
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}
.checkpoint-desc { font-size: 0.875rem; line-height: 1.7; margin-bottom: 1rem; }
.checkpoint-tags { display: flex; gap: 0.5rem; flex-wrap: wrap; margin-bottom: 1rem; }
.checkpoint-link {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--accent-purple);
  transition: color var(--transition);
}
.checkpoint-link:hover { color: var(--text-primary); }