.page-about {
  --about-rail: 208px;
  --about-gap: clamp(24px, 4vw, 56px);
  --about-tl-pad: clamp(22px, 3vw, 38px);
  background: var(--ink);
  color: var(--text-strong);
  padding-bottom: clamp(56px, 9vw, 112px);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding-top: clamp(18px, 3vw, 34px);
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(20px, 3vw, 40px);
  align-items: end;
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.02fr) minmax(0, 0.98fr);
  }
}

.page-about .about-hero__kicker {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--lime);
}

.page-about h1 {
  margin: 0 0 18px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(2.1rem, 5.4vw, 4.2rem);
  line-height: 1.06;
  letter-spacing: -0.02em;
  text-wrap: balance;
}

.page-about .about-hero__lede {
  margin: 0;
  max-width: 34em;
  font-family: var(--font-body);
  font-size: clamp(1rem, 1.2vw, 1.08rem);
  line-height: 1.78;
  color: var(--text-mid);
}

.page-about .about-hero__figure {
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--ink-soft);
  margin: 0;
}

/* ---------- 数据条带 ---------- */
.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-top: clamp(28px, 4vw, 44px);
  background: var(--graphite);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

@media (min-width: 760px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .about-stats__item {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: clamp(16px, 2vw, 24px);
  background: var(--paper);
  color: var(--brown);
}

.page-about .about-stats__num {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(1.45rem, 2.6vw, 2.05rem);
  letter-spacing: -0.01em;
  color: var(--brand-deep);
}

.page-about .about-stats__num .unit {
  font-size: 0.52em;
  letter-spacing: 0.06em;
  color: var(--graphite);
}

.page-about .about-stats__label {
  font-family: var(--font-body);
  font-size: 0.82rem;
  letter-spacing: 0.02em;
  color: var(--graphite);
}

/* ---------- 双栏主体 ---------- */
.page-about .about-body {
  display: grid;
  gap: var(--about-gap);
  margin-top: clamp(40px, 6vw, 76px);
}

@media (min-width: 960px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
  }
}

.page-about .about-rail {
  align-self: start;
}

@media (min-width: 960px) {
  .page-about .about-rail {
    position: sticky;
    top: 92px;
  }
}

.page-about .about-rail__title {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--text-soft);
}

.page-about .about-rail__list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-rail__link {
  display: block;
  padding: 7px 0 7px 14px;
  margin-left: -1px;
  border-left: 2px solid transparent;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.02em;
  color: var(--text-soft);
  text-decoration: none;
  transition: color 140ms var(--ease), border-color 140ms var(--ease);
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  color: var(--lime);
  border-left-color: var(--lime);
}

@media (max-width: 959px) {
  .page-about .about-rail__list {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    padding-bottom: 4px;
  }

  .page-about .about-rail__link {
    padding: 6px 13px;
    margin-left: 0;
    border: 1px solid var(--line-soft);
    border-radius: var(--pill);
  }

  .page-about .about-rail__link:hover,
  .page-about .about-rail__link:focus-visible {
    border-color: var(--lime);
  }
}

/* ---------- 章节 ---------- */
.page-about .about-sec {
  padding-bottom: clamp(34px, 5vw, 58px);
  margin-bottom: clamp(34px, 5vw, 58px);
  border-bottom: 1px solid var(--line-soft);
  scroll-margin-top: 96px;
}

.page-about .about-sec:last-child {
  padding-bottom: 0;
  margin-bottom: 0;
  border-bottom: 0;
}

.page-about .about-sec__note {
  display: inline-block;
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--amber);
}

.page-about .about-sec h2 {
  margin: 0 0 20px;
  max-width: 20em;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.5rem, 3vw, 2.1rem);
  line-height: 1.16;
  letter-spacing: -0.015em;
}

.page-about .about-p {
  margin: 0 0 1.1em;
  max-width: 34em;
  font-family: var(--font-body);
  font-size: 1.0625rem;
  line-height: 1.8;
  color: var(--text-mid);
}

.page-about .about-p:last-child {
  margin-bottom: 0;
}

.page-about .about-p a {
  color: var(--lime);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
  transition: text-decoration-thickness 140ms var(--ease);
}

.page-about .about-p a:hover,
.page-about .about-p a:focus-visible {
  text-decoration-thickness: 3px;
}

.page-about .about-p--drop::first-letter {
  float: left;
  padding: 0.04em 0.14em 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 3.5em;
  line-height: 0.84;
  color: var(--lime);
}

/* ---------- 版本时间轴 ---------- */
.page-about .about-tl {
  position: relative;
  margin-top: clamp(20px, 3vw, 32px);
  padding-left: var(--about-tl-pad);
}

.page-about .about-tl::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 10px;
  bottom: 10px;
  width: 2px;
  border-radius: 2px;
  background: linear-gradient(180deg, var(--brand) 0%, var(--lime) 58%, var(--graphite) 100%);
}

.page-about .about-tl__item {
  position: relative;
  padding-bottom: clamp(26px, 3.4vw, 40px);
}

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

.page-about .about-tl__item::before {
  content: "";
  position: absolute;
  left: calc(-1 * var(--about-tl-pad) + 1px);
  top: 0.42em;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--ink);
  border: 2px solid var(--graphite);
  transition: border-color 160ms var(--ease), background-color 160ms var(--ease);
}

.page-about .about-tl__item:hover::before,
.page-about .about-tl__item:focus-within::before {
  border-color: var(--lime);
  background: var(--lime);
}

.page-about .about-tl__item--flag::before {
  border-color: var(--lime);
  background: var(--brand);
}

.page-about .about-tl__ver {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--text-soft);
}

.page-about .about-tl__item--flag .about-tl__ver {
  color: var(--lime);
}

.page-about .about-tl h3 {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.16rem;
  line-height: 1.38;
  letter-spacing: -0.01em;
  color: var(--text-strong);
}

.page-about .about-tl__hint {
  margin: 10px 0 0;
  padding-left: 12px;
  border-left: 2px solid var(--graphite);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.04em;
  line-height: 1.6;
  color: var(--text-soft);
  opacity: 0.62;
  transition: opacity 160ms var(--ease), color 160ms var(--ease), border-color 160ms var(--ease);
}

.page-about .about-tl__item:hover .about-tl__hint,
.page-about .about-tl__item:focus-within .about-tl__hint {
  opacity: 1;
  color: var(--lime);
  border-left-color: var(--lime);
}

/* ---------- 图 ---------- */
.page-about .about-fig {
  margin: clamp(20px, 3vw, 32px) 0;
  max-width: 640px;
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--ink-soft);
}

.page-about .about-fig--archive {
  max-width: 520px;
  margin-left: auto;
  margin-right: auto;
}

/* ---------- 数据卡片条 ---------- */
.page-about .about-bars {
  display: grid;
  gap: 12px;
  margin: clamp(20px, 3vw, 30px) 0;
}

@media (min-width: 720px) {
  .page-about .about-bars {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .about-bar {
  padding: clamp(14px, 2vw, 20px);
  border-radius: var(--radius-md);
  background: var(--paper);
  color: var(--brown);
  transition: box-shadow 160ms var(--ease);
}

.page-about .about-bar:hover,
.page-about .about-bar:focus-visible {
  box-shadow: 0 0 0 2px var(--lime);
}

.page-about .about-bar:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 3px;
}

.page-about .about-bar__label {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  color: var(--graphite);
}

.page-about .about-bar__num {
  display: block;
  margin-top: 4px;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(1.5rem, 2.8vw, 2.1rem);
  letter-spacing: -0.01em;
  color: var(--brand-deep);
}

.page-about .about-bar__num .unit {
  font-size: 0.48em;
  letter-spacing: 0.06em;
  color: var(--graphite);
}

.page-about .about-bar__note {
  display: block;
  max-height: 0;
  margin-top: 0;
  overflow: hidden;
  opacity: 0;
  font-family: var(--font-body);
  font-size: 0.82rem;
  line-height: 1.62;
  color: var(--graphite);
  transition: max-height 200ms var(--ease), opacity 180ms var(--ease), margin-top 200ms var(--ease);
}

.page-about .about-bar:hover .about-bar__note,
.page-about .about-bar:focus .about-bar__note,
.page-about .about-bar:focus-within .about-bar__note {
  max-height: 6em;
  margin-top: 9px;
  opacity: 1;
}

/* ---------- 合作 ---------- */
.page-about .about-collab {
  display: grid;
  gap: 14px;
  margin: clamp(18px, 3vw, 26px) 0 0;
  padding: 0;
  list-style: none;
}

@media (min-width: 720px) {
  .page-about .about-collab {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .about-collab__item {
  padding: clamp(16px, 2.2vw, 22px);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius-md);
  background: var(--ink-soft);
  transition: border-color 160ms var(--ease);
}

.page-about .about-collab__item:hover {
  border-color: var(--lime);
}

.page-about .about-collab__name {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.02rem;
  letter-spacing: -0.005em;
  color: var(--lime);
}

.page-about .about-collab__desc {
  margin: 0;
  font-family: var(--font-body);
  font-size: 0.9rem;
  line-height: 1.72;
  color: var(--text-mid);
}

.page-about .about-contact {
  margin-top: clamp(22px, 3vw, 34px);
  border-top: 1px solid var(--line-soft);
}

.page-about .about-contact__row {
  display: grid;
  gap: 4px;
  padding: 12px 0;
  border-bottom: 1px solid var(--line-soft);
}

@media (min-width: 640px) {
  .page-about .about-contact__row {
    grid-template-columns: 120px minmax(0, 1fr);
    align-items: baseline;
    gap: 18px;
  }
}

.page-about .about-contact__k {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  color: var(--text-soft);
}

.page-about .about-contact__v {
  font-family: var(--font-body);
  font-size: 0.95rem;
  line-height: 1.66;
  color: var(--text-strong);
  word-break: break-word;
}

.page-about .about-contact__v--mono {
  font-family: var(--font-mono);
  letter-spacing: 0.01em;
}

.page-about .about-cta {
  margin: clamp(22px, 3vw, 32px) 0 0;
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail__link,
  .page-about .about-tl__item::before,
  .page-about .about-tl__hint,
  .page-about .about-bar,
  .page-about .about-bar__note,
  .page-about .about-collab__item,
  .page-about .about-p a {
    transition: none;
  }
}