/* ==========================================================================
   sections.css — numbered chapters, stack grid, cards, timeline, facts, certs
   ========================================================================== */

/* --- Chapter shell ------------------------------------------------------- */
.chapter {
  position: relative;
  padding: var(--section-y) var(--pad-x);
  border-bottom: 1px solid var(--line-soft);
}

.chapter--alt {
  background: var(--bg-alt);
}

.chapter__head {
  display: flex;
  align-items: baseline;
  gap: clamp(0.9rem, 2.5vw, 2.5rem);
  margin-bottom: clamp(2.5rem, 7vh, 5rem);
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--line);
}

.chapter__num {
  font-family: var(--font-mono);
  font-size: clamp(0.72rem, 1vw, 0.85rem);
  letter-spacing: 0.22em;
  color: var(--accent);
}

.chapter__title {
  font-size: clamp(2.4rem, 7vw, 6rem);
  letter-spacing: -0.05em;
}

.chapter__body {
  max-width: 74ch;
  color: var(--ink-dim);
}

/* --- Stack grid ---------------------------------------------------------- */
.stack {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 2.25rem 2rem;
  margin-top: clamp(3rem, 8vh, 5.5rem);
  padding-top: 2.25rem;
  border-top: 1px solid var(--line-soft);
}

.stack__col h3 {
  margin-bottom: 1.1rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

.stack__col li {
  padding: 0.4rem 0;
  font-size: 0.98rem;
  color: var(--ink-dim);
  border-bottom: 1px solid var(--line-soft);
  transition: color 0.3s var(--ease), border-color 0.3s var(--ease);
}

.stack__col li:hover {
  color: var(--ink);
  border-color: var(--accent);
}

/* --- Cards --------------------------------------------------------------- */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 280px), 1fr));
  gap: 1px;
  margin-top: clamp(3rem, 8vh, 5.5rem);
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
}

.card {
  padding: clamp(1.6rem, 3vw, 2.4rem);
  background: var(--bg);
  transition: background 0.4s var(--ease);
}

.chapter--alt .card {
  background: var(--bg-alt);
}

.card:hover {
  background: var(--bg-raise);
}

.card__num {
  display: block;
  margin-bottom: 1.4rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.2em;
  color: var(--accent);
}

.card h3 {
  margin-bottom: 0.8rem;
  font-size: 1.22rem;
  letter-spacing: -0.02em;
}

.card p {
  margin: 0;
  font-size: 0.93rem;
  line-height: 1.65;
  color: var(--ink-dim);
}

/* --- Timeline ------------------------------------------------------------ */
.timeline {
  margin-top: clamp(3rem, 8vh, 5.5rem);
  border-top: 1px solid var(--line-soft);
}

.timeline li {
  display: grid;
  grid-template-columns: minmax(9rem, 15rem) 1fr;
  gap: 1rem 2rem;
  padding: 1.9rem 0;
  border-bottom: 1px solid var(--line-soft);
}

.timeline__when {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  padding-top: 0.35rem;
}

.timeline h3 {
  margin-bottom: 0.45rem;
  font-size: clamp(1.25rem, 2.2vw, 1.75rem);
  letter-spacing: -0.03em;
}

.timeline p {
  margin: 0;
  font-size: 0.95rem;
  color: var(--ink-dim);
}

/* --- Facts --------------------------------------------------------------- */
.facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 2.25rem 2rem;
  margin-top: clamp(3rem, 8vh, 5.5rem);
  padding-top: 2.5rem;
  border-top: 1px solid var(--line-soft);
}

.fact__value {
  display: block;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(3rem, 6.5vw, 5.25rem);
  line-height: 0.95;
  letter-spacing: -0.055em;
  font-feature-settings: "tnum" 1;
  color: var(--ink);
  margin-bottom: 0.8rem;
}

.fact__label {
  display: block;
  max-width: 26ch;
  font-size: 0.86rem;
  line-height: 1.55;
  color: var(--ink-faint);
}

/* --- Certifications ------------------------------------------------------ */
.certs {
  margin-top: clamp(3rem, 8vh, 5rem);
}

.certs h3 {
  margin-bottom: 1.4rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

.certs li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.5rem 1.5rem;
  padding: 1.05rem 0;
  font-size: 1.02rem;
  color: var(--ink-dim);
  border-bottom: 1px solid var(--line-soft);
}

.certs__when {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--ink-faint);
}

/* --- Responsive ---------------------------------------------------------- */
@media (min-width: 1080px) {
  .stack,
  .facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (max-width: 520px) {
  .stack,
  .facts {
    grid-template-columns: minmax(0, 1fr);
  }
}

@media (max-width: 700px) {
  .chapter__head {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.75rem;
  }

  .timeline li {
    grid-template-columns: 1fr;
    gap: 0.6rem;
  }

  .timeline__when {
    padding-top: 0;
  }
}