.page-about {
  --about-hair: rgba(234, 227, 210, .16);
  --about-paper-ink: #14171C;
  --about-paper-muted: #5B5445;
  --about-paper-hair: rgba(20, 23, 28, .16);
  --about-em: var(--gold-light);
  --about-em-soft: var(--gold);
  display: block;
}

.page-about :focus-visible {
  outline: 2px solid var(--gold-light);
  outline-offset: 2px;
}

/* ============ 首屏 ============ */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: 40px 0 44px;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  top: -70px;
  right: -10%;
  width: min(680px, 74vw);
  height: 250px;
  background: linear-gradient(118deg, rgba(201, 162, 39, .30), rgba(56, 225, 208, .13) 56%, rgba(16, 49, 47, 0) 80%);
  transform: skewY(-7deg);
  pointer-events: none;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: auto 0 0 0;
  height: 1px;
  background: linear-gradient(90deg, var(--gold), rgba(201, 162, 39, 0) 62%);
  opacity: .7;
}

.page-about .about-hero .shell {
  position: relative;
  z-index: 1;
}

.page-about .crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 36px;
  font-size: 13px;
}

.page-about .crumbs__item {
  color: var(--slate);
  text-decoration: none;
}

.page-about .crumbs__item:last-child {
  color: var(--chalk);
}

.page-about a.crumbs__item:hover {
  color: var(--gold-light);
}

.page-about .crumbs__sep {
  color: rgba(167, 173, 184, .5);
}

.page-about .about-hero__kicker {
  margin: 0 0 18px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--gold);
}

.page-about .about-hero__title {
  margin: 0;
  max-width: 15em;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(34px, 6.2vw, 74px);
  line-height: 1.08;
  letter-spacing: -.02em;
  color: var(--chalk);
}

.page-about .about-hero__lead {
  margin: 28px 0 0;
  max-width: 46em;
  font-size: 17px;
  line-height: 1.8;
  color: #C8CEDA;
}

.page-about .about-facts {
  list-style: none;
  margin: 44px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--about-hair);
  border: 1px solid var(--about-hair);
}

.page-about .about-fact {
  background: var(--panel);
  padding: 18px 16px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .about-fact__v {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 24px;
  line-height: 1;
  color: var(--gold-light);
}

.page-about .about-fact__k {
  font-size: 13px;
  color: var(--slate);
}

/* ============ 主体骨架 ============ */
.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
  padding: 48px 0 72px;
}

.page-about .about-toc__title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--slate);
}

.page-about .about-toc__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding-bottom: 6px;
  scrollbar-width: thin;
}

.page-about .about-toc__list li {
  flex: 0 0 auto;
}

.page-about .about-toc__list a {
  display: block;
  white-space: nowrap;
  padding: 7px 12px;
  border: 1px solid var(--about-hair);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--slate);
  text-decoration: none;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-toc__list a:hover {
  color: var(--gold-light);
  border-color: var(--gold);
  background: rgba(201, 162, 39, .1);
}

.page-about .about-stream {
  display: grid;
  gap: 28px;
  min-width: 0;
}

/* ============ 章节通用 ============ */
.page-about .about-sec {
  position: relative;
  padding: 32px 22px 36px;
  color: var(--chalk);
  background: var(--panel);
  border: 2px solid var(--about-hair);
  box-shadow: var(--shadow);
  min-width: 0;
}

.page-about .about-sec--paper {
  background: var(--paper);
  color: var(--about-paper-ink);
  border: 1px solid var(--paper-shade);
  --about-em: #8A6E12;
  --about-em-soft: #B08C1C;
}

.page-about .about-sec--ink {
  --about-em: var(--gold-light);
  --about-em-soft: var(--gold);
}

.page-about .about-sec--teal {
  background: var(--teal);
  border-color: rgba(201, 162, 39, .42);
  --about-em: var(--gold-light);
  --about-em-soft: var(--gold);
}

.page-about .about-sec__head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: 22px;
}

.page-about .about-sec__no {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 13px;
  letter-spacing: .1em;
  color: var(--about-em);
  flex: 0 0 auto;
}

.page-about .about-sec__title {
  margin: 0;
  flex: 0 1 auto;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(23px, 3.6vw, 36px);
  line-height: 1.2;
  letter-spacing: -.02em;
  color: inherit;
}

.page-about .about-sec__head::after {
  content: "";
  flex: 1 1 auto;
  align-self: center;
  height: 1px;
  background: currentColor;
  opacity: .2;
}

.page-about .about-sec__lead {
  margin: 0 0 26px;
  max-width: 44em;
  font-size: 16px;
  line-height: 1.8;
  opacity: .86;
}

.page-about .about-sec__foot {
  margin: 26px 0 0;
  font-size: 14px;
  line-height: 1.8;
  opacity: .74;
}

.page-about .about-sec p {
  font-size: 16px;
  line-height: 1.8;
}

.page-about .about-sec p + p {
  margin-top: 1.1em;
}

.page-about .about-sec--paper p {
  color: var(--about-paper-ink);
}

.page-about .about-sec--paper .about-sec__lead,
.page-about .about-sec--paper .about-sec__foot {
  color: var(--about-paper-muted);
  opacity: 1;
}

.page-about .crown-mark {
  position: absolute;
  top: 22px;
  right: 20px;
  width: 118px;
  height: 118px;
  color: var(--gold);
  opacity: .06;
  pointer-events: none;
}

/* ============ 双栏 ============ */
.page-about .about-cols {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
  align-items: start;
}

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

.page-about .about-list {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .about-list li {
  position: relative;
  padding-left: 20px;
  font-size: 15px;
  line-height: 1.75;
}

.page-about .about-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .68em;
  width: 9px;
  height: 3px;
  background: var(--about-em-soft);
}

.page-about .about-side {
  border-left: 2px solid var(--about-em-soft);
  padding: 4px 0 4px 18px;
  min-width: 0;
}

.page-about .about-side__title {
  margin: 0 0 16px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--about-em);
}

.page-about .entry-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 16px;
  counter-reset: entry;
}

.page-about .entry-list__item {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 4px 10px;
  align-items: baseline;
}

.page-about .entry-list__no {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--about-em);
}

.page-about .entry-list__item a {
  font-size: 16px;
  font-weight: 600;
  color: inherit;
  text-decoration: none;
  border-bottom: 1px solid var(--about-em-soft);
  padding-bottom: 2px;
}

.page-about .entry-list__item a:hover {
  color: var(--about-em);
}

.page-about .entry-list__d {
  grid-column: 2;
  font-size: 13px;
  line-height: 1.6;
  opacity: .7;
}

.page-about .partner-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .partner-list li {
  display: grid;
  gap: 4px;
}

.page-about .partner-list strong {
  font-size: 15px;
  font-weight: 600;
}

.page-about .partner-list span {
  font-size: 13px;
  line-height: 1.6;
  color: var(--about-paper-muted);
}

/* ============ 图片 ============ */
.page-about .about-figure {
  margin: 0;
  padding: 8px;
  background: var(--ink);
  border: 2px solid var(--about-hair);
  box-shadow: var(--shadow-sm);
  min-width: 0;
}

.page-about .about-sec--paper .about-figure {
  border-color: rgba(20, 23, 28, .22);
  box-shadow: 4px 4px 0 rgba(20, 23, 28, .28);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border: 1px solid rgba(201, 162, 39, .34);
  object-fit: cover;
}

.page-about .about-figure figcaption {
  padding: 10px 4px 2px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .04em;
  color: var(--slate);
}

.page-about .about-figure--wide {
  margin-bottom: 30px;
}

/* ============ 时间轴 ============ */
.page-about .timeline {
  position: relative;
  padding-left: 40px;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 10px;
  bottom: 18px;
  width: 4px;
  background: linear-gradient(180deg, var(--gold), var(--cyan));
}

.page-about .stage {
  position: relative;
  padding-bottom: 30px;
}

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

.page-about .stage::before {
  content: "";
  position: absolute;
  left: -37px;
  top: 6px;
  width: 14px;
  height: 14px;
  background: var(--panel);
  border: 3px solid var(--gold);
}

.page-about .stage:nth-child(1)::before { border-color: #C9A227; }
.page-about .stage:nth-child(2)::before { border-color: #A8B455; }
.page-about .stage:nth-child(3)::before { border-color: #7FBE87; }
.page-about .stage:nth-child(4)::before { border-color: #5BCFB4; }
.page-about .stage:nth-child(5)::before { border-color: var(--cyan); }

.page-about .stage__meta {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 11.5px;
  letter-spacing: .08em;
  color: var(--gold);
}

.page-about .stage__title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: 21px;
  line-height: 1.35;
  letter-spacing: -.01em;
}

.page-about .stage__desc {
  margin: 0;
  max-width: 42em;
  font-size: 15.5px;
  line-height: 1.8;
  color: #C8CEDA;
}

.page-about .stage__more {
  margin-top: 12px;
}

.page-about .stage__summary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  border: 1px solid var(--line-strong);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .06em;
  color: var(--gold-light);
  cursor: pointer;
  list-style: none;
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .stage__summary::-webkit-details-marker {
  display: none;
}

.page-about .stage__summary::before {
  content: "＋";
  font-size: 13px;
  line-height: 1;
}

.page-about .stage__more[open] .stage__summary::before {
  content: "－";
}

.page-about .stage__summary:hover {
  border-color: var(--gold);
  background: rgba(201, 162, 39, .1);
}

.page-about .stage__list {
  list-style: none;
  margin: 14px 0 0;
  padding: 0 0 0 16px;
  display: grid;
  gap: 8px;
  border-left: 2px solid rgba(56, 225, 208, .34);
}

.page-about .stage__list li {
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--slate);
}

/* ============ 发布节律 ============ */
.page-about .cadence {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
}

.page-about .cadence__item {
  border-top: 4px solid var(--about-em-soft);
  padding-top: 14px;
}

.page-about .cadence__k {
  display: block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--about-paper-muted);
}

.page-about .cadence__v {
  display: block;
  margin-top: 8px;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: 27px;
  letter-spacing: -.02em;
  color: var(--about-em);
}

.page-about .cadence__d {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--about-paper-muted);
}

/* ============ 区域与资质 ============ */
.page-about .region-stats {
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--about-hair);
  border: 1px solid var(--about-hair);
}

.page-about .region-stat {
  background: var(--panel);
  padding: 18px 16px;
}

.page-about .region-stat dt {
  font-size: 13px;
  color: var(--slate);
  margin-bottom: 10px;
}

.page-about .region-stat dd {
  margin: 0;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 26px;
  line-height: 1;
  color: var(--gold-light);
}

/* ============ 下一步 ============ */
.page-about .next-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
}

.page-about .next-links__item {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  grid-template-areas:
    "no title arrow"
    "no desc  arrow";
  gap: 2px 14px;
  align-items: center;
  padding: 16px 18px;
  background: rgba(11, 12, 14, .38);
  border: 2px solid rgba(234, 227, 210, .2);
  text-decoration: none;
  color: var(--chalk);
  transition: border-color var(--dur) var(--ease), transform var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .next-links__item:hover {
  border-color: var(--gold);
  transform: translateY(-2px);
  background: rgba(11, 12, 14, .6);
}

.page-about .next-links__no {
  grid-area: no;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--gold);
}

.page-about .next-links__t {
  grid-area: title;
  font-size: 17px;
  font-weight: 600;
}

.page-about .next-links__d {
  grid-area: desc;
  font-size: 13px;
  line-height: 1.6;
  color: var(--slate);
}

.page-about .next-links__arrow {
  grid-area: arrow;
  font-size: 18px;
  color: var(--cyan);
}

/* ============ 响应式 ============ */
@media (min-width: 640px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

@media (min-width: 900px) {
  .page-about .about-hero {
    padding: 56px 0 56px;
  }

  .page-about .about-sec {
    padding: 40px 36px 44px;
  }

  .page-about .about-cols {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, .85fr);
    gap: 40px;
  }

  .page-about .about-cols__main > .about-figure,
  .page-about .about-cols > .about-figure {
    grid-column: auto;
  }

  .page-about .region-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .next-links {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
  }
}

@media (min-width: 960px) {
  .page-about .about-body {
    grid-template-columns: 208px minmax(0, 1fr);
    gap: 52px;
    padding: 64px 0 96px;
  }

  .page-about .about-toc {
    position: sticky;
    top: 132px;
    align-self: start;
  }

  .page-about .about-toc__list {
    display: grid;
    gap: 2px;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .about-toc__list a {
    border: none;
    border-left: 2px solid transparent;
    padding: 8px 10px;
    white-space: normal;
  }

  .page-about .about-toc__list a:hover {
    border-left-color: var(--gold);
  }

  .page-about .stage__title {
    font-size: 23px;
  }
}

@media (min-width: 1180px) {
  .page-about .cadence {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 22px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .next-links__item,
  .page-about .about-toc__list a {
    transition: none;
  }

  .page-about .next-links__item:hover {
    transform: none;
  }
}