.page-about {
  --about-year-size: clamp(2.5rem, 10vw, 4.5rem);
  --about-pad-xs: 1.25rem;
  --about-pad-sm: 1.5rem;
  --about-rail-mobile: 27px;
  --about-rail-desktop: 235px;
  position: relative;
  background-color: var(--color-bg);
  color: var(--color-text);
  overflow-x: hidden;
}

/* ============ HERO ============ */
.page-about__hero {
  position: relative;
  padding: calc(var(--header-h) + 2.5rem) 0 3.5rem;
  overflow: hidden;
  background:
    linear-gradient(115deg, var(--color-bg) 55%, rgba(27, 58, 91, 0.65) 55%),
    radial-gradient(ellipse at 82% 18%, rgba(0, 229, 255, 0.1), transparent 42%);
  border-bottom: 1px solid var(--color-line);
}

.page-about__hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(
    -42deg,
    transparent 0,
    transparent 16px,
    rgba(57, 255, 136, 0.05) 16px,
    rgba(57, 255, 136, 0.05) 18px
  );
  pointer-events: none;
}

.page-about__hero-body {
  position: relative;
  z-index: 1;
  max-width: 720px;
}

.page-about__hero-title {
  margin: 0.75rem 0 1.25rem;
  font-family: var(--font-title);
  font-size: clamp(1.6rem, 5.5vw, 3rem);
  font-weight: 900;
  line-height: 1.18;
  letter-spacing: 0.01em;
}

.page-about__hero .lead {
  max-width: 520px;
}

.page-about__hero-year {
  position: absolute;
  right: 0.75rem;
  bottom: 0.5rem;
  z-index: 0;
  text-align: right;
  pointer-events: none;
  opacity: 0.45;
}

.page-about__hero-year-num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(3.5rem, 12vw, 7.5rem);
  font-weight: 700;
  line-height: 0.95;
  color: transparent;
  -webkit-text-stroke: 1.5px var(--color-data);
}

.page-about__hero-year-label {
  display: block;
  margin-top: 0.35rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.38em;
  color: var(--color-text-dim);
}

/* ============ SECTION HEADS ============ */
.page-about__section-head {
  margin-bottom: 2rem;
}

.page-about__section-title {
  position: relative;
  margin: 0.5rem 0 0;
  padding-bottom: 0.75rem;
  font-family: var(--font-title);
  font-size: clamp(1.4rem, 3.5vw, 2.1rem);
  font-weight: 900;
  line-height: 1.3;
}

.page-about__section-title::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 56px;
  height: 4px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-data));
}

/* ============ ORIGIN ============ */
.page-about__origin-grid {
  display: grid;
  gap: 2.5rem;
  margin-top: 2.5rem;
}

.page-about__prose p {
  margin: 0 0 1.15rem;
  line-height: 1.95;
}

.page-about__dropcap::first-letter {
  float: left;
  margin: 0.08em 0.12em 0 0;
  font-family: var(--font-title);
  font-size: 3.2em;
  font-weight: 900;
  line-height: 0.9;
  color: var(--color-accent);
}

.page-about__origin-panel {
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 1.5rem;
  min-height: 260px;
}

.page-about__origin-panel .stat-grid {
  grid-template-columns: repeat(2, 1fr);
}

.page-about__stat {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.page-about__stat .data-number {
  font-size: clamp(1.4rem, 4vw, 2rem);
}

.page-about__origin-panel .note-vertical {
  align-self: flex-end;
}

/* ============ EVOLUTION ============ */
.page-about__evolution {
  position: relative;
  background:
    radial-gradient(ellipse at 15% 60%, rgba(27, 58, 91, 0.3), transparent 55%),
    var(--color-bg);
}

.page-about__evolution-grid {
  display: grid;
  gap: 2.5rem;
  margin-top: 2.5rem;
}

.page-about__evo-figure {
  position: relative;
  margin: 0;
  overflow: hidden;
  background: var(--color-bg-card);
  clip-path: polygon(0 0, calc(100% - 18px) 0, 100% 18px, 100% 100%, 0% 100%);
}

.page-about__evo-figure img {
  display: block;
  width: 100%;
  height: auto;
}

.page-about__evo-figure::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 4px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-data));
}

.page-about__evo-timeline {
  position: relative;
  margin-top: 2.5rem;
  padding-left: var(--about-pad-sm);
  border-left: 2px solid rgba(0, 229, 255, 0.25);
}

.page-about__evo-step {
  position: relative;
  padding-bottom: var(--about-pad-sm);
}

.page-about__evo-step:last-child {
  padding-bottom: 0;
}

.page-about__evo-step::before {
  content: '';
  position: absolute;
  left: calc(var(--about-pad-sm) * -1 - 5px);
  top: 0.35em;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--color-data);
  box-shadow: 0 0 8px rgba(0, 229, 255, 0.4);
}

.page-about__evo-step-year {
  display: block;
  margin-bottom: 0.3rem;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--color-accent);
}

.page-about__evo-step p {
  margin: 0;
  font-size: 0.95rem;
  line-height: 1.7;
  color: var(--color-text-dim);
}

/* ============ GATE ============ */
.page-about__gate {
  position: relative;
  overflow: hidden;
  background:
    linear-gradient(105deg, transparent 72%, rgba(0, 229, 255, 0.05) 72%),
    var(--color-bg);
}

.page-about__gate::before {
  content: '';
  position: absolute;
  top: -12%;
  right: -18%;
  width: 48%;
  height: 36%;
  transform: skewY(-6deg);
  background: rgba(57, 255, 136, 0.04);
  pointer-events: none;
}

.page-about__gate-grid {
  display: grid;
  gap: var(--about-pad-xs);
  margin-top: 2.5rem;
}

.page-about__gate-card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  transition: transform var(--transition), border-color var(--transition);
}

.page-about__gate-card:hover {
  transform: translateY(-4px);
  border-color: rgba(57, 255, 136, 0.4);
}

.page-about__gate-num {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.2em;
  color: var(--color-data);
}

.page-about__gate-note {
  margin-top: 2rem;
}

/* ============ DATA ============ */
.page-about__data {
  position: relative;
  background:
    radial-gradient(ellipse at 80% 30%, rgba(57, 255, 136, 0.06), transparent 50%),
    var(--color-bg);
}

.page-about__data-grid {
  display: grid;
  gap: 2.5rem;
  margin-top: 2.5rem;
}

.page-about__data-figure {
  position: relative;
  margin: 0;
  overflow: hidden;
  background: var(--color-bg-card);
}

.page-about__data-figure img {
  display: block;
  width: 100%;
  height: auto;
}

.page-about__data-content .lead {
  line-height: 1.7;
}

.page-about__data-stats {
  grid-template-columns: repeat(2, 1fr);
  margin: 1.75rem 0;
}

.page-about__data-note {
  padding: 0.85rem 1rem;
  border-left: 3px solid var(--color-accent);
  background: var(--color-accent-dim);
  font-size: 0.95rem;
  line-height: 1.7;
  color: var(--color-text);
}

/* ============ MILESTONES ============ */
.page-about__timeline {
  position: relative;
  margin-top: 3rem;
}

.page-about__timeline::before {
  content: '';
  position: absolute;
  left: var(--about-rail-mobile);
  top: 0.25rem;
  bottom: 2rem;
  width: 2px;
  background: linear-gradient(to bottom, var(--color-accent), var(--color-data) 70%, transparent);
  opacity: 0.35;
}

.page-about__milestone {
  position: relative;
  padding-bottom: 2.5rem;
  padding-left: 3.75rem;
}

.page-about__milestone:last-child {
  padding-bottom: 0;
}

.page-about__milestone::before {
  content: '';
  position: absolute;
  left: 20px;
  top: 0.45em;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--color-accent);
  box-shadow: 0 0 0 4px rgba(57, 255, 136, 0.14), 0 0 14px rgba(57, 255, 136, 0.4);
  z-index: 1;
}

.page-about__milestone-year {
  margin-bottom: 0.5rem;
}

.page-about__milestone-num {
  font-family: var(--font-mono);
  font-size: var(--about-year-size);
  font-weight: 700;
  line-height: 1;
  color: var(--color-data);
}

.page-about__milestone-body .accordion__item {
  margin-top: 0.85rem;
}

/* ============ CLOSING ============ */
.page-about__closing {
  position: relative;
  padding-bottom: 4rem;
}

.page-about__dataflow {
  position: relative;
  margin: 0;
  overflow: hidden;
  border-radius: 4px;
}

.page-about__dataflow img {
  display: block;
  width: 100%;
  height: auto;
}

.page-about__closing-card {
  position: relative;
  margin-top: 2rem;
  padding: 2rem 1.75rem;
  background: var(--color-bg-card);
  border-top: 3px solid var(--color-accent);
  text-align: center;
}

.page-about__closing-card h2 {
  margin: 0 0 0.75rem;
  font-family: var(--font-title);
  font-size: clamp(1.3rem, 3vw, 1.8rem);
  font-weight: 900;
}

.page-about__closing-card p {
  color: var(--color-text-dim);
  line-height: 1.7;
}

.page-about__closing-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.75rem;
  margin-top: 1.5rem;
}

/* ============ RESPONSIVE ============ */
@media (min-width: 640px) {
  .page-about__hero-year {
    opacity: 0.7;
  }

  .page-about__gate-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .page-about__closing-card {
    margin: -3.5rem 1.5rem 0;
    padding: 2.5rem;
  }

  .page-about__dataflow {
    margin-bottom: 1.5rem;
  }
}

@media (min-width: 900px) {
  .page-about__hero {
    padding: calc(var(--header-h) + 4rem) 0 5rem;
  }

  .page-about__hero-title {
    font-size: 3.2rem;
  }

  .page-about__hero-year {
    right: 2rem;
    opacity: 1;
  }

  .page-about__origin-grid {
    grid-template-columns: 1.15fr 0.85fr;
    align-items: start;
    gap: 3.5rem;
  }

  .page-about__origin-panel {
    position: sticky;
    top: calc(var(--header-h) + 2rem);
  }

  .page-about__evolution-grid {
    grid-template-columns: 1fr 1fr;
    align-items: center;
    gap: 3.5rem;
  }

  .page-about__data-grid {
    grid-template-columns: 0.9fr 1.1fr;
    align-items: center;
    gap: 3.5rem;
  }

  .page-about__data-figure {
    order: 1;
  }

  .page-about__data-content {
    order: 2;
  }

  .page-about__timeline::before {
    left: var(--about-rail-desktop);
  }

  .page-about__milestone {
    display: grid;
    grid-template-columns: 200px 72px 1fr;
    align-items: start;
    padding-left: 0;
    padding-bottom: 3rem;
  }

  .page-about__milestone::before {
    left: 229px;
    top: 0.5em;
  }

  .page-about__milestone-year {
    grid-column: 1;
    margin-bottom: 0;
    padding-top: 0.1rem;
    text-align: right;
  }

  .page-about__milestone-body {
    grid-column: 3;
  }

  .page-about__milestone-num {
    font-size: clamp(3rem, 5vw, 4.5rem);
  }
}