/* ============================================================
   CHALLENGE SECTION — shared two-column scrollytelling component
   Left: compact list of pain points, one active/focused at a time.
   Right: sticky timeline that fills in progressively (checklist-style)
   as the user scrolls past each point on the left.
   Rendered by assets/challenge-section.js from a page-supplied config -
   see that file for the data shape. Relies on this site's shared design
   tokens (--t1/--t2/--t3, --primary, --acs, --card, --cb, --r, --r-sm,
   --sh, --tr, --nav-h, --font-mono), defined in each page's own
   :root block.
   ============================================================ */
.problem-split {
  display: grid;
  grid-template-columns: 7fr 5fr; /* ~58.3% / 41.7% */
  gap: 64px;
  position: relative;
}

.challenge-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.challenge-point {
  display: grid;
  grid-template-columns: 40px 1fr;
  column-gap: 20px;
  /* Height follows content - no fixed/min height. Cards end up different
     heights depending on their text, which is expected. */
  align-items: flex-start;
  padding: 24px 32px;
  border-left: 3px solid transparent;
  border-radius: var(--r-sm);
  transition: background var(--tr), border-left-color var(--tr);
}

.challenge-point__icon-wrap {
  display: flex;
  align-items: center;
  justify-content: center;
}

.challenge-point__icon-wrap svg {
  opacity: 0.45;
  transition: opacity var(--tr);
}

.challenge-point__title {
  font-weight: 600;
  /* Matches .step__title (How It Works cards) */
  font-size: 0.9375rem;
  color: var(--t3);
  line-height: 1.3;
  letter-spacing: -0.015em;
  margin-bottom: 8px;
  transition: color var(--tr), font-weight var(--tr);
}

.challenge-point__text {
  /* Matches .step__text (How It Works cards) */
  font-size: 0.875rem;
  color: var(--t3);
  line-height: 1.6;
  transition: color var(--tr);
}

.challenge-point__text--strong {
  font-weight: 600;
  margin-top: 8px;
}

.challenge-point.is-active {
  background: var(--acs);
  border-left-color: var(--primary);
}

.challenge-point.is-active .challenge-point__icon-wrap svg { opacity: 1; }

.challenge-point.is-active .challenge-point__title {
  color: var(--t1);
  font-weight: 700;
}

.challenge-point.is-active .challenge-point__text {
  color: var(--t2);
}

.challenge-point.is-active .challenge-point__text--strong {
  color: var(--t1);
}

/* ---- Timeline card - sticky on desktop, static + stacked below on tablet/mobile.
   Height is intentionally NOT forced to match the left column - it sizes to its
   own content (padding + item spacing below) rather than being propped up. ---- */
.timeline-card {
  position: sticky;
  top: calc(var(--nav-h) + 32px);
  background: var(--card);
  border: 1px solid var(--cb);
  border-radius: var(--r);
  padding: 40px;
  box-shadow: var(--sh);
}

.timeline-items {
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.timeline-item {
  display: grid;
  /* --timeline-time-w is set from JS once the real time labels are measured,
     so "Week 0" and "Month 1 – Month 6" both get exactly the room they need. */
  grid-template-columns: var(--timeline-time-w, 80px) 1fr;
  column-gap: 12px;
  align-items: flex-start;
}

/* Severity progression, yellow -> dark red. --stage-color is darkened from
   the requested hue where needed to clear WCAG AA (4.5:1) for text on white.
   Timelines with fewer stages just use a subset of these classes;
   --red-dark is available for a 6th/terminal step. */
.timeline-item--yellow     { --stage-color: #976e08; }
.timeline-item--amber      { --stage-color: #a5670b; }
.timeline-item--orange     { --stage-color: #b75c0f; }
.timeline-item--orange-red { --stage-color: #cc4920; }
.timeline-item--red        { --stage-color: #c93b3b; }
.timeline-item--red-dark   { --stage-color: #8f2020; }

/* ---- Continuous-line variant (opt-in via config.progressCursor) ----
   One continuous vertical gradient line behind all stages. */
.timeline-items--progress-line {
  position: relative;
}

.timeline-progress-track {
  position: absolute;
  top: 0;
  bottom: 0;
  /* Centered in the gap right after the time column, whatever width that
     column was measured to (see sizeTimeColumn in challenge-section.js). */
  left: calc(var(--timeline-time-w, 80px) + 6px);
  width: 2px;
  border-radius: 1px;
  transform: translateX(-50%);
  /* Gradient stops are set inline by JS from the same --stage-color values
     used per stage, so it always matches whatever stages are configured. */
}

.timeline-item__time {
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 700;
  color: var(--t2);
  letter-spacing: 0.04em;
  white-space: nowrap;
}

.timeline-item__label {
  /* Matches .challenge-point__text (left column descriptive text) */
  font-size: 0.875rem;
  /* Neutral until reached - each stage picks up its own severity color as the
     matching challenge point is scrolled past, and keeps it (checklist-style)
     until the user scrolls back up above that point. #6b7280 clears WCAG AA
     (4.83:1 on white) - var(--t3) alone was only 2.54:1. */
  color: #6b7280;
  line-height: 1.5;
  transition: color 0.3s ease, font-weight 0.3s ease;
}

.timeline-item.is-reached .timeline-item__label {
  color: var(--stage-color);
  font-weight: 700;
}

/* The sticky two-column scrollytelling effect only makes sense with room to
   spare on desktop - below this width, stack timeline under the list, static. */
@media (max-width: 1024px) {
  .problem-split {
    grid-template-columns: 1fr;
    gap: 40px;
  }
  .timeline-card {
    position: static;
    top: auto;
  }
}