/* ============================================================
   About / document page
   ============================================================ */

.shell {
  position: relative;
  z-index: 2;
  width: var(--shell);
  margin: 0 auto;
  padding: var(--sp-4) var(--sp-5) var(--sp-7);
}

.doc { display: grid; gap: var(--sp-4); }

.doc__sec {
  display: grid;
  grid-template-columns: 52px 1fr;
  gap: var(--sp-4);
  align-items: start;
}

.doc__num {
  position: relative;
  padding-top: 6px;
  color: var(--quantum);
  font-weight: 500;
}
/* observation line descending from the section number */
.doc__num::after {
  content: "";
  position: absolute;
  left: 6px;
  top: 30px;
  bottom: -22px;
  width: 1px;
  background: linear-gradient(to bottom, var(--quantum), transparent);
  opacity: 0.5;
}

.doc__title {
  font-family: var(--font-hand);
  font-size: clamp(30px, 4.4vw, 46px);
  font-weight: 700;
  letter-spacing: 0.01em;
  line-height: 1.02;
  margin-bottom: var(--sp-3);
}

.doc__lead {
  font-size: var(--fs-lead);
  line-height: 1.7;
  color: var(--text);
  max-width: var(--measure);
  margin-bottom: var(--sp-3);
}

.doc__text {
  color: var(--muted);
  line-height: 1.8;
  max-width: var(--measure);
}

.doc__divider {
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--border-strong), transparent);
}

.doc__kicker {
  position: relative;
  padding-left: var(--sp-3);
  margin: var(--sp-4) 0 var(--sp-2);
  font-weight: 500;
  color: var(--text);
}
.doc__kicker::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.3em;
  bottom: 0.3em;
  width: 2px;
  background: linear-gradient(to bottom, transparent, var(--quantum), transparent);
}

.doc__list {
  padding-left: var(--sp-4);
  margin-bottom: var(--sp-2);
}
.doc__list li { margin: 6px 0; color: var(--muted); }

.doc__footer {
  margin-top: var(--sp-3);
  padding-top: var(--sp-4);
  border-top: 1px solid var(--border);
}

@media (max-width: 640px) {
  .doc__sec { grid-template-columns: 40px 1fr; gap: var(--sp-3); }
}