.page-about {
  --about-rail: 172px;
  position: relative;
  overflow-x: clip;
  padding-bottom: clamp(2.5rem, 7vw, 5rem);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  padding-block: clamp(4.5rem, 12vw, 9rem) clamp(2.5rem, 6vw, 4rem);
  background:
    radial-gradient(120% 90% at 88% 6%, rgba(124, 58, 237, .28), transparent 58%),
    radial-gradient(90% 70% at 4% 96%, rgba(34, 211, 238, .13), transparent 62%),
    linear-gradient(180deg, var(--ink-900), var(--ink-950));
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  z-index: -1;
  right: -16%;
  top: -22%;
  width: min(760px, 88vw);
  aspect-ratio: 1 / 1;
  transform: rotate(-14deg);
  border-radius: 48px;
  background: linear-gradient(150deg, rgba(124, 58, 237, .22), rgba(34, 211, 238, .06) 58%, transparent 78%);
  pointer-events: none;
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.75rem, 5vw, 3rem);
  align-items: start;
}

.page-about .crumbs {
  margin-top: 1.1rem;
  font-size: .82rem;
}

.page-about .about-hero__title {
  margin: 1.35rem 0 0;
  font-size: clamp(2.05rem, 6.4vw, 4.4rem);
  font-weight: 300;
  line-height: 1.07;
  letter-spacing: .012em;
  color: var(--text);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  background-image: linear-gradient(118deg, var(--text) 18%, var(--text-dim) 82%);
}

.page-about .about-hero__lede {
  margin-top: 1.5rem;
  max-width: 62ch;
  font-size: clamp(1rem, 1.5vw, 1.08rem);
  line-height: 1.85;
  color: var(--text-soft);
}

/* 档案速览玻璃牌 */
.page-about .about-facts {
  padding: clamp(1.35rem, 3.4vw, 2rem);
  border-radius: var(--radius);
}

.page-about .about-facts__title {
  margin: 0 0 1rem;
  font-size: .78rem;
  font-weight: 500;
  letter-spacing: .24em;
  color: var(--text-soft);
}

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

.page-about .about-facts__row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  padding: .62rem .2rem;
  border-bottom: 1px solid rgba(42, 58, 106, .55);
}

.page-about .about-facts__row:last-child {
  border-bottom: 0;
}

.page-about .about-facts__k {
  font-size: .84rem;
  color: var(--text-soft);
}

.page-about .about-facts__v {
  font-size: 1.02rem;
  letter-spacing: .05em;
  color: var(--amber);
  white-space: nowrap;
}

.page-about .about-facts__note {
  margin: 1.1rem 0 0;
  font-size: .78rem;
  line-height: 1.75;
  color: var(--text-soft);
}

/* ---------- 章节目录 ---------- */
.page-about .about-index {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: linear-gradient(90deg, rgba(16, 26, 58, .72), rgba(10, 16, 36, .3));
}

.page-about .about-index__inner {
  padding-block: clamp(1.1rem, 3vw, 1.6rem);
}

.page-about .about-index__list {
  list-style: none;
  margin: 1rem 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: .5rem clamp(1rem, 3vw, 2.4rem);
}

.page-about .about-index__list a {
  display: inline-flex;
  align-items: baseline;
  gap: .55rem;
  padding: .28rem .08rem;
  font-size: .93rem;
  color: var(--text-dim);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .2s var(--ease), border-color .2s var(--ease);
}

.page-about .about-index__list a .mono {
  font-size: .74rem;
  letter-spacing: .12em;
  color: var(--violet);
}

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

/* ---------- 主体画布 ---------- */
.page-about .about-body {
  margin-top: clamp(2.2rem, 6vw, 4.5rem);
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.5rem, 4vw, 2.5rem);
}

.page-about .about-rail {
  display: none;
}

.page-about .about-block {
  border-top: 1px solid rgba(42, 58, 106, .5);
  padding-block: clamp(2.1rem, 6vw, 3.8rem);
  scroll-margin-top: calc(var(--header-h) + 1.6rem);
}

.page-about .about-block:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .h-sec {
  margin: .85rem 0 0;
  font-size: clamp(1.55rem, 3.4vw, 2.3rem);
  line-height: 1.26;
  letter-spacing: .01em;
  transition: color .25s var(--ease);
}

.page-about .about-block:target .h-sec {
  color: var(--cyan);
}

.page-about .about-block__lede {
  margin: 1.05rem 0 0;
  max-width: 66ch;
  font-size: clamp(.98rem, 1.4vw, 1.05rem);
  line-height: 1.85;
  color: var(--text-soft);
}

.page-about .h-mini {
  margin: 0 0 .5rem;
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: .02em;
  color: var(--text);
}

.page-about .about-col p,
.page-about .about-timeline__body p,
.page-about .about-rules-list p {
  margin: .45rem 0 0;
  font-size: .94rem;
  line-height: 1.85;
  color: var(--text-soft);
}

/* ---------- 01 定位三栏 ---------- */
.page-about .about-cols {
  margin-top: clamp(1.5rem, 4vw, 2.3rem);
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.2rem, 3vw, 2rem);
}

.page-about .about-col {
  position: relative;
  padding-top: 1.05rem;
  border-top: 1px solid var(--line);
}

.page-about .about-col::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  width: 44px;
  height: 1px;
  background: var(--violet);
}

.page-about .about-col:nth-child(2)::before {
  background: var(--cyan);
}

.page-about .about-col:nth-child(3)::before {
  background: var(--amber);
}

/* ---------- 02 时间线 ---------- */
.page-about .about-timeline {
  list-style: none;
  margin: clamp(1.5rem, 4vw, 2.3rem) 0 0;
  padding: 0 0 0 1.4rem;
  border-left: 1px solid var(--line);
}

.page-about .about-timeline__item {
  position: relative;
  padding-bottom: clamp(1.1rem, 3vw, 1.8rem);
}

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

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: calc(-1.4rem - 4.5px);
  top: .85rem;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--ink-950);
  border: 1px solid var(--violet);
  box-shadow: 0 0 0 4px rgba(124, 58, 237, .14);
  transition: background .22s var(--ease), border-color .22s var(--ease), box-shadow .22s var(--ease);
}

.page-about .about-timeline__item:hover::before {
  background: var(--cyan);
  border-color: var(--cyan);
  box-shadow: 0 0 0 5px rgba(34, 211, 238, .18), 0 0 18px rgba(34, 211, 238, .5);
}

.page-about .about-timeline__body {
  padding: .7rem 1rem;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  transition: background .25s var(--ease), border-color .25s var(--ease), transform .25s var(--ease);
}

.page-about .about-timeline__item:hover .about-timeline__body {
  background: rgba(16, 26, 58, .62);
  border-color: var(--line);
  transform: translateX(5px);
}

.page-about .about-timeline__no {
  display: block;
  font-size: .74rem;
  letter-spacing: .24em;
  color: var(--violet);
}

.page-about .about-timeline__meta {
  margin-top: .55rem;
  font-size: .73rem;
  letter-spacing: .1em;
  color: var(--text-soft);
}

/* ---------- 图片帧 ---------- */
.page-about .media-frame img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .about-figure {
  margin: clamp(1.7rem, 4vw, 2.5rem) 0 0;
}

/* ---------- 03 合作 ---------- */
.page-about .about-partners {
  margin-top: clamp(1.5rem, 4vw, 2.3rem);
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.4rem, 4vw, 2.4rem);
}

.page-about .about-partners__text .h-mini {
  margin-top: 1.7rem;
}

.page-about .about-partners__text .h-mini:first-child {
  margin-top: 0;
}

.page-about .about-partners__figure {
  margin: 0;
}

.page-about .about-rules {
  margin: .7rem 0 0;
}

.page-about .about-rules li {
  font-size: .93rem;
  line-height: 1.85;
  color: var(--text-soft);
}

/* ---------- 04 守则清单 ---------- */
.page-about .about-rules-list {
  list-style: none;
  margin: clamp(1.5rem, 4vw, 2.3rem) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1rem, 3vw, 1.7rem);
}

.page-about .about-rules-list li {
  padding: .15rem 0 .15rem 1.15rem;
  border-left: 1px solid rgba(42, 58, 106, .9);
  transition: border-color .22s var(--ease);
}

.page-about .about-rules-list li:hover {
  border-left-color: var(--cyan);
}

.page-about .about-rules-list__no {
  display: block;
  font-size: .72rem;
  letter-spacing: .24em;
  color: var(--cyan);
  margin-bottom: .4rem;
}

/* ---------- 05 合规 ---------- */
.page-about .about-legal {
  margin-top: clamp(1.5rem, 4vw, 2.3rem);
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.2rem, 3vw, 2rem);
}

.page-about .about-legal__stamp {
  padding: clamp(1.2rem, 3vw, 1.7rem);
  border-radius: var(--radius);
}

.page-about .about-legal__label {
  margin: 0;
  font-size: .73rem;
  letter-spacing: .24em;
  color: var(--text-soft);
}

.page-about .about-legal__code {
  margin: .7rem 0 0;
  font-size: clamp(1.1rem, 2.6vw, 1.55rem);
  letter-spacing: .05em;
  color: var(--amber);
  word-break: break-all;
}

.page-about .about-legal__hint {
  margin: .7rem 0 0;
  font-size: .81rem;
  line-height: 1.75;
  color: var(--text-soft);
}

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

.page-about .about-legal__contacts li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: .35rem 1rem;
  padding: .85rem .2rem;
  border-bottom: 1px solid rgba(42, 58, 106, .55);
}

.page-about .about-legal__contacts li:first-child {
  border-top: 1px solid rgba(42, 58, 106, .55);
}

.page-about .about-legal__k {
  min-width: 5.4rem;
  font-size: .81rem;
  color: var(--text-soft);
}

.page-about .about-legal__v {
  font-size: .94rem;
  color: var(--text);
  word-break: break-all;
}

.page-about .about-legal__copy {
  display: inline-flex;
  align-items: baseline;
  gap: .6rem;
  padding: 0;
  border: 0;
  background: none;
  font: inherit;
  cursor: pointer;
  color: var(--text);
}

.page-about .about-legal__copy .copy-mail__text {
  font-size: .94rem;
  word-break: break-all;
}

.page-about .about-legal__copy .copy-mail__hint {
  font-size: .7rem;
  letter-spacing: .12em;
  color: var(--cyan);
  border-bottom: 1px dashed rgba(34, 211, 238, .5);
}

.page-about .about-legal__copy:hover .copy-mail__hint,
.page-about .about-legal__copy:focus-visible .copy-mail__hint {
  color: var(--text);
  border-bottom-color: var(--text);
}

.page-about .about-legal__note {
  margin: 1.2rem 0 0;
  max-width: 70ch;
  font-size: .83rem;
  line-height: 1.8;
  color: var(--text-soft);
}

.page-about .about-legal__figure {
  margin: clamp(1.7rem, 4vw, 2.5rem) 0 0;
}

/* ---------- 后续路径 ---------- */
.page-about .about-next {
  margin-top: clamp(2.2rem, 6vw, 3.8rem);
  padding-top: clamp(1.5rem, 4vw, 2.2rem);
  border-top: 1px solid var(--line);
}

.page-about .about-next__list {
  list-style: none;
  margin: 1.1rem 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: .9rem;
}

.page-about .about-next__list a {
  display: block;
  padding: 1rem 1.1rem;
  font-size: .91rem;
  line-height: 1.7;
  color: var(--text-dim);
  text-decoration: none;
  background: rgba(16, 26, 58, .5);
  border: 1px solid rgba(42, 58, 106, .75);
  border-radius: var(--radius-sm);
  transition: color .22s var(--ease), background .22s var(--ease), border-color .22s var(--ease);
}

.page-about .about-next__list a .mono {
  display: block;
  margin-bottom: .4rem;
  font-size: .71rem;
  letter-spacing: .22em;
  color: var(--violet);
}

.page-about .about-next__list a:hover,
.page-about .about-next__list a:focus-visible {
  color: var(--text);
  background: rgba(16, 26, 58, .84);
  border-color: var(--cyan);
}

/* ---------- 响应式 ---------- */
@media (min-width: 760px) {
  .page-about .about-cols {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-rules-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-next__list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: clamp(1rem, 3vw, 1.9rem);
  }
}

@media (min-width: 880px) {
  .page-about .about-partners {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .about-legal {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  }
}

@media (min-width: 920px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: clamp(2rem, 5vw, 4.2rem);
  }

  .page-about .about-rail {
    display: block;
  }

  .page-about .about-rail__text {
    position: sticky;
    top: calc(var(--header-h) + 2.5rem);
    display: block;
    padding-top: .3rem;
    writing-mode: vertical-rl;
    font-size: .7rem;
    letter-spacing: .34em;
    color: var(--text-soft);
  }
}

@media (min-width: 960px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.45fr) minmax(0, 1fr);
    gap: clamp(2.5rem, 6vw, 5rem);
  }
}

@media (max-width: 420px) {
  .page-about .about-facts__row {
    flex-wrap: wrap;
    gap: .2rem .8rem;
  }

  .page-about .about-legal__k {
    min-width: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition: none !important;
  }
}