.page-about {
  --about-rail: 4.75rem;
  --about-measure: 40rem;
  --about-gap-x: clamp(1rem, 3vw, 2.75rem);
  --about-gap-y: clamp(2.5rem, 5vw, 4.5rem);
  --about-chess: rgba(243, 241, 232, .045);
}

.page-about img {
  max-width: 100%;
  height: auto;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding-block: clamp(1.75rem, 4vw, 3rem) clamp(2rem, 4vw, 3.25rem);
  border-bottom: var(--line);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  top: -7rem;
  right: -9rem;
  width: clamp(15rem, 34vw, 26rem);
  aspect-ratio: 1;
  background-image:
    linear-gradient(45deg, var(--about-chess) 25%, transparent 25%, transparent 75%, var(--about-chess) 75%),
    linear-gradient(45deg, var(--about-chess) 25%, transparent 25%, transparent 75%, var(--about-chess) 75%);
  background-size: 42px 42px;
  background-position: 0 0, 21px 21px;
  -webkit-mask-image: radial-gradient(circle at 32% 32%, #000 0%, transparent 72%);
  mask-image: radial-gradient(circle at 32% 32%, #000 0%, transparent 72%);
  pointer-events: none;
}

.page-about .about-hero__eyebrow {
  margin-top: clamp(1.5rem, 3vw, 2.25rem);
  color: var(--cyan);
}

.page-about .about-hero__title {
  max-width: 20ch;
  margin: .75rem 0 0;
  font-style: italic;
}

.page-about .about-hero__lede {
  max-width: var(--about-measure);
  margin: 1.15rem 0 0;
}

.page-about .about-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(1.75rem, 4vw, 2.75rem) 0 0;
  padding: 0;
  list-style: none;
  background: var(--grid);
  border-top: var(--line);
  border-bottom: var(--line);
}

.page-about .about-fact {
  display: flex;
  flex-direction: column;
  gap: .45rem;
  padding: 1rem .9rem 1.15rem;
  background: var(--ink);
}

.page-about .about-fact__k {
  font-family: var(--font-mono);
  font-size: .6875rem;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .about-fact__v {
  font-family: var(--font-mono);
  font-size: 1.0625rem;
  font-variant-numeric: tabular-nums;
  letter-spacing: -.01em;
  color: var(--cyan);
}

@media (min-width: 768px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

/* ---------- 章节骨架 ---------- */

.page-about .chapter {
  padding-block: var(--about-gap-y);
}

.page-about .chapter__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: .85rem 1.25rem;
}

@media (min-width: 900px) {
  .page-about .chapter__grid {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: 0 var(--about-gap-x);
  }
}

.page-about .chapter__mark {
  display: flex;
  align-items: flex-start;
}

.page-about .chapter__num {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: clamp(1.9rem, 6vw, 3.25rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.04em;
  font-variant-numeric: tabular-nums;
  color: transparent;
  -webkit-text-stroke: 1px var(--grid);
  transition: -webkit-text-stroke-color .35s var(--ease);
}

@media (min-width: 900px) {
  .page-about .chapter__num {
    writing-mode: vertical-rl;
    text-orientation: mixed;
  }
}

.page-about .chapter:target .chapter__num {
  -webkit-text-stroke-color: var(--cyan);
}

.page-about .chapter__body {
  position: relative;
  padding-left: clamp(1rem, 2.5vw, 1.75rem);
  border-left: var(--line);
}

.page-about .chapter__body::before {
  content: "";
  position: absolute;
  left: -1px;
  top: .35rem;
  width: 2px;
  height: 2.75rem;
  background: var(--cyan);
}

.page-about .chapter__eyebrow {
  margin: 0 0 .55rem;
  color: var(--muted);
}

.page-about .chapter__title {
  margin: 0 0 1.1rem;
}

.page-about .chapter__anchor {
  color: inherit;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .25s var(--ease), border-color .25s var(--ease);
}

.page-about .chapter__anchor:hover,
.page-about .chapter__anchor:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.page-about .chapter__body p {
  max-width: var(--about-measure);
  margin: 0 0 1rem;
}

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

/* ---------- 通用小列表 ---------- */

.page-about .about-list {
  display: grid;
  gap: .55rem;
  margin: 1rem 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-list > li {
  position: relative;
  padding-left: 1.15rem;
  color: var(--muted);
  line-height: 1.7;
}

.page-about .about-list > li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .82em;
  width: .55rem;
  height: 1px;
  background: var(--cyan);
  opacity: .85;
}

/* ---------- 图文分栏 ---------- */

.page-about .about-split {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(1.25rem, 3vw, 2.25rem);
  align-items: start;
  margin-top: clamp(1.25rem, 3vw, 2rem);
}

@media (min-width: 768px) {
  .page-about .about-split--media-right {
    grid-template-columns: minmax(0, 1fr) minmax(0, .82fr);
  }

  .page-about .about-split--media-left {
    grid-template-columns: minmax(0, .82fr) minmax(0, 1.18fr);
  }
}

.page-about .about-split__text p {
  max-width: var(--about-measure);
}

.page-about .about-figure {
  position: relative;
  margin: 0;
}

.page-about .about-figure--wide {
  margin-bottom: clamp(1.5rem, 3.5vw, 2.25rem);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  object-fit: cover;
  border: 1px solid var(--grid);
  filter: saturate(.78) brightness(.92) contrast(1.05);
}

.page-about .about-figure--3x2 img {
  aspect-ratio: 3 / 2;
}

.page-about .about-figure--wide img {
  aspect-ratio: 4 / 3;
}

/* ---------- 两条内容线 ---------- */

.page-about .about-lines {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  margin-top: clamp(1.5rem, 3.5vw, 2.25rem);
  background: var(--grid);
  border-top: var(--line);
  border-bottom: var(--line);
}

@media (min-width: 768px) {
  .page-about .about-lines {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

.page-about .about-line {
  position: relative;
  padding: clamp(1.25rem, 3vw, 1.85rem);
  background-color: var(--ink);
}

.page-about .about-line::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 2px;
}

.page-about .about-line--a {
  background-image: linear-gradient(180deg, rgba(46, 230, 200, .08), transparent 58%);
}

.page-about .about-line--a::before {
  background: var(--cyan);
}

.page-about .about-line--b {
  background-image: linear-gradient(180deg, rgba(255, 107, 44, .08), transparent 58%);
}

.page-about .about-line--b::before {
  background: var(--orange);
}

.page-about .about-line h3 {
  margin: .35rem 0 .6rem;
}

.page-about .about-line > p {
  max-width: 34rem;
  margin: 0;
  color: var(--muted);
}

/* ---------- 赛季刻度 ---------- */

.page-about .about-scale {
  margin: clamp(1.75rem, 4vw, 2.75rem) 0 0;
  padding: 1.25rem 0 .35rem;
  border-top: var(--line);
}

.page-about .about-scale__cap {
  font-family: var(--font-mono);
  font-size: .6875rem;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: .85rem;
}

.page-about .about-scale svg {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .about-scale__axis {
  stroke: var(--grid);
  stroke-width: 1;
}

.page-about .about-scale__tick {
  cursor: help;
}

.page-about .about-scale__tick line {
  stroke: var(--grid);
  stroke-width: 1;
}

.page-about .about-scale__tick circle {
  fill: var(--ink);
  stroke: var(--teal);
  stroke-width: 1.5;
  transition: fill .25s var(--ease), stroke .25s var(--ease);
}

.page-about .about-scale__tick text {
  fill: var(--muted);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .06em;
  transition: fill .25s var(--ease);
}

.page-about .about-scale__tick:hover circle,
.page-about .about-scale__tick:focus-visible circle {
  fill: var(--cyan);
  stroke: var(--cyan);
}

.page-about .about-scale__tick:hover text,
.page-about .about-scale__tick:focus-visible text {
  fill: var(--ivory);
}

/* ---------- 表格 ---------- */

.page-about .about-table-wrap {
  overflow-x: auto;
}

.page-about .about-table__cap {
  caption-side: top;
  text-align: left;
  font-family: var(--font-mono);
  font-size: .6875rem;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--muted);
  padding-bottom: .75rem;
}

.page-about .about-table-wrap .data-table {
  min-width: 32rem;
}

/* ---------- 更正流程 ---------- */

.page-about .about-steps {
  display: grid;
  gap: 0;
  margin: clamp(1.5rem, 3.5vw, 2.25rem) 0 0;
  padding: 0;
  list-style: none;
  border-top: var(--line);
}

.page-about .about-step {
  display: grid;
  grid-template-columns: 2.75rem minmax(0, 1fr);
  gap: 0 .85rem;
  padding: 1.1rem 0;
  border-bottom: var(--line);
}

.page-about .about-step__n {
  padding-top: .3rem;
  font-family: var(--font-mono);
  font-size: .8125rem;
  letter-spacing: .1em;
  font-variant-numeric: tabular-nums;
  color: var(--cyan);
}

.page-about .about-step h3 {
  margin: 0 0 .35rem;
}

.page-about .about-step p {
  margin: 0;
  max-width: var(--about-measure);
  color: var(--muted);
}

/* ---------- 强调块与渠道 ---------- */

.page-about .about-quote {
  max-width: var(--about-measure);
  margin: clamp(1.5rem, 3.5vw, 2.25rem) 0 0;
  padding: .35rem 0 .35rem clamp(1rem, 2.5vw, 1.5rem);
  border-left: 2px solid var(--orange);
  background: linear-gradient(90deg, rgba(255, 107, 44, .08), transparent 70%);
  color: var(--ivory);
  font-size: 1.0625rem;
  line-height: 1.75;
}

.page-about .about-channels {
  max-width: var(--about-measure);
  margin-top: clamp(1.25rem, 3vw, 1.75rem);
  padding: 1rem 1.15rem;
  background: var(--orange-deep);
  border-left: 2px solid var(--orange);
}

.page-about .about-channels__line {
  margin: 0;
  font-family: var(--font-mono);
  font-size: .875rem;
  line-height: 1.85;
  font-variant-numeric: tabular-nums;
  color: var(--ivory);
  word-break: break-word;
}

.page-about .about-channels__line + .about-channels__line {
  margin-top: .4rem;
}

.page-about .about-channels a {
  color: var(--cyan);
}

.page-about .about-channels a:hover {
  color: var(--orange);
}

/* ---------- 尾链接 ---------- */

.page-about .about-links {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem 1.5rem;
  max-width: var(--about-measure);
  margin: clamp(1.5rem, 3.5vw, 2.25rem) 0 0;
  padding-top: 1.25rem;
  border-top: var(--line);
}

.page-about .about-links a {
  font-family: var(--font-mono);
  font-size: .8125rem;
  letter-spacing: .06em;
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(46, 230, 200, .35);
  transition: color .25s var(--ease), border-color .25s var(--ease);
}

.page-about .about-links a:hover,
.page-about .about-links a:focus-visible {
  color: var(--orange);
  border-bottom-color: var(--orange);
}

/* ---------- 窄屏收口 ---------- */

@media (max-width: 767px) {
  .page-about .chapter__body {
    padding-left: 1rem;
  }

  .page-about .chapter__body::before {
    height: 1.75rem;
  }

  .page-about .about-hero__title {
    max-width: none;
  }

  .page-about .about-channels__line {
    font-size: .8125rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .chapter__num,
  .page-about .about-scale__tick circle,
  .page-about .about-scale__tick text,
  .page-about .chapter__anchor,
  .page-about .about-links a {
    transition: none;
  }
}