.page-about {
  background: var(--paper);
  color: var(--ink-soft);
  --about-shift: 22px;
}

/* ---------- 面包屑 ---------- */
.page-about .about-head {
  padding-block: clamp(18px, 3vw, 34px) clamp(10px, 1.6vw, 18px);
}

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

/* ---------- 首屏 ---------- */
.page-about .about-masthead {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 4vw, 44px);
  padding-bottom: clamp(28px, 5vw, 62px);
  border-bottom: 1px solid var(--line);
}

.page-about .about-masthead__title {
  margin: 8px 0 20px;
  color: var(--ink);
  font-size: clamp(36px, 5.6vw, 80px);
  line-height: 1.03;
  letter-spacing: -0.02em;
  font-weight: 300;
}

.page-about .about-masthead__lede {
  margin: 0 0 26px;
  max-width: 46ch;
  font-size: clamp(16px, 1.4vw, 18px);
  line-height: 1.88;
  color: var(--ink-soft);
}

.page-about .about-masthead__acts {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

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

.page-about .about-fact {
  background: var(--white);
  padding: 18px 16px 20px;
}

.page-about .about-fact__num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(23px, 2.5vw, 32px);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--ink);
}

.page-about .about-fact__num em {
  font-style: normal;
  font-size: 0.46em;
  margin-left: 3px;
  letter-spacing: 0;
  color: var(--crimson);
}

.page-about .about-fact__label {
  display: block;
  margin-top: 9px;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--slate);
}

/* ---------- 章节索引条 ---------- */
.page-about .about-index {
  position: sticky;
  top: var(--header-h);
  z-index: 5;
  background: var(--ink);
  border-block: 1px solid rgba(192, 138, 46, 0.3);
}

.page-about .chapter-index--bar {
  display: flex;
  align-items: stretch;
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
  overflow-x: auto;
  counter-reset: chapter;
  scrollbar-width: thin;
}

.page-about .chapter-index--bar li {
  flex: 0 0 auto;
  counter-increment: chapter;
}

.page-about .chapter-index--bar a {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 15px 16px 13px;
  color: var(--on-dark-dim);
  text-decoration: none;
  font-size: 13px;
  letter-spacing: 0.06em;
  white-space: nowrap;
  border-bottom: 2px solid transparent;
  transition: color 0.25s ease, border-color 0.25s ease;
}

.page-about .chapter-index--bar a:hover,
.page-about .chapter-index--bar a:focus-visible {
  color: var(--paper);
}

.page-about .chapter-index--bar a[aria-current="true"] {
  color: var(--paper);
  border-bottom-color: var(--crimson);
}

.page-about .chapter-index--bar .chapter-index__num {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--gold);
}

.page-about .chapter-index--bar .chapter-index__num::before {
  content: counter(chapter, decimal-leading-zero);
}

.page-about .chapter-index--bar a[aria-current="true"] .chapter-index__num {
  color: var(--crimson);
}

/* ---------- 分屏骨架 ---------- */
.page-about .about-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(36px, 5vw, 60px);
  padding-block: clamp(36px, 6vw, 76px) clamp(48px, 7vw, 96px);
  align-items: start;
}

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

/* ---------- 正文章节 ---------- */
.page-about .about-chapter {
  position: relative;
  padding-block: clamp(28px, 4vw, 50px);
  border-top: 1px solid var(--line);
  scroll-margin-top: calc(var(--header-h) + 68px);
}

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

.page-about .about-chapter h2 {
  margin: 8px 0 20px;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(25px, 3.1vw, 38px);
  line-height: 1.24;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .about-chapter .prose p {
  margin: 0 0 1.15em;
  font-size: 17px;
  line-height: 1.9;
}

.page-about .about-chapter .prose a,
.page-about .about-fold a,
.page-about .about-timeline__more a {
  color: var(--crimson);
  text-decoration: none;
  border-bottom: 1px solid rgba(200, 52, 43, 0.35);
}

.page-about .about-chapter .prose a:hover,
.page-about .about-fold a:hover,
.page-about .about-timeline__more a:hover {
  border-bottom-color: var(--crimson);
}

/* ---------- 图片 ---------- */
.page-about .media {
  margin: 0 0 22px;
}

.page-about .media img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border-radius: var(--radius);
}

.page-about .media__cap {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.7;
  letter-spacing: 0.02em;
  color: var(--slate);
}

/* ---------- 时间轴 ---------- */
.page-about .about-timeline {
  position: relative;
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 12px;
  bottom: 18px;
  width: 2px;
  background: linear-gradient(180deg, var(--gold) 0%, rgba(192, 138, 46, 0.16) 100%);
}

.page-about .about-node {
  position: relative;
  padding-left: 30px;
  padding-bottom: clamp(20px, 2.8vw, 32px);
}

.page-about .about-node::before {
  content: "";
  position: absolute;
  left: 0;
  top: 7px;
  width: 12px;
  height: 12px;
  box-sizing: border-box;
  border-radius: 50%;
  background: var(--paper);
  border: 2px solid var(--gold);
  transition: background-color 0.2s ease, border-color 0.2s ease;
}

.page-about .about-node:hover::before {
  background: var(--gold);
  border-color: var(--crimson);
}

.page-about .about-node__year {
  margin: 0 0 4px;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(18px, 2vw, 22px);
  line-height: 1.1;
  letter-spacing: 0.04em;
  color: var(--ink);
}

.page-about .about-node h3 {
  margin: 0 0 8px;
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 500;
  letter-spacing: 0.01em;
  color: var(--ink);
}

.page-about .about-node p {
  margin: 0 0 8px;
  font-size: 16px;
  line-height: 1.85;
}

.page-about .about-node__note {
  margin: 0;
  padding-left: 12px;
  border-left: 2px solid var(--line);
  font-size: 14px;
  line-height: 1.75;
  color: var(--slate);
  transition: color 0.2s ease, border-color 0.2s ease;
}

.page-about .about-node:hover .about-node__note,
.page-about .about-node:focus-within .about-node__note {
  color: var(--crimson);
  border-left-color: var(--crimson);
}

.page-about .about-timeline__more {
  margin: 18px 0 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--slate);
}

/* ---------- 团队 ---------- */
.page-about .about-team {
  list-style: none;
  margin: 24px 0 26px;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .about-team__item {
  background: var(--white);
  padding: 18px 16px;
}

.page-about .about-team__num {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 30px;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--ink);
}

.page-about .about-team__label {
  display: block;
  margin-top: 8px;
  font-size: 15px;
  font-weight: 500;
  color: var(--ink);
}

.page-about .about-team__desc {
  display: block;
  margin-top: 5px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--slate);
}

.page-about .about-flow__lead {
  margin: 0 0 16px;
  font-size: 17px;
  line-height: 1.9;
}

.page-about .about-flow {
  list-style: none;
  margin: 0;
  padding: 0;
  counter-reset: flow;
}

.page-about .about-flow li {
  position: relative;
  padding: 0 0 18px 0;
  counter-increment: flow;
}

.page-about .about-flow li::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 4px;
  width: 26px;
  height: 1px;
  background: var(--line);
}

.page-about .about-flow li:last-child::after {
  display: none;
}

.page-about .about-flow__k {
  display: block;
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--gold);
}

.page-about .about-flow__k::before {
  content: counter(flow, decimal-leading-zero) " / ";
  color: var(--crimson);
}

.page-about .about-flow p {
  margin: 0;
  font-size: 16px;
  line-height: 1.85;
}

/* ---------- 内容板块 ---------- */
.page-about .about-blocks {
  list-style: none;
  margin: 0 0 26px;
  padding: 0;
  counter-reset: block;
}

.page-about .about-blocks li {
  position: relative;
  padding: 16px 0 16px 20px;
  border-bottom: 1px solid var(--line);
  counter-increment: block;
}

.page-about .about-blocks li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 22px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--gold);
}

.page-about .about-blocks li:first-child {
  border-top: 1px solid var(--line);
}

.page-about .about-blocks h3 {
  margin: 0 0 6px;
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 500;
  color: var(--ink);
  letter-spacing: 0.01em;
}

.page-about .about-blocks h3::before {
  content: counter(block, decimal-leading-zero);
  display: inline-block;
  margin-right: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--crimson);
  vertical-align: 1px;
}

.page-about .about-blocks p {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink-soft);
}

.page-about .about-fold {
  border: 1px solid var(--line);
  border-left: 3px solid var(--gold);
  background: var(--white);
  padding: 4px 18px 4px 16px;
  border-radius: var(--radius);
}

.page-about .about-fold .fold__summary {
  padding-block: 14px;
  font-size: 15px;
  font-weight: 500;
  color: var(--ink);
  cursor: pointer;
}

.page-about .about-fold .fold__body {
  padding-bottom: 14px;
}

.page-about .about-fold .fold__body p {
  margin: 0 0 10px;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink-soft);
}

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

/* ---------- 两条路径 ---------- */
.page-about .about-ways {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about .about-way {
  display: block;
  padding: 22px 20px 20px;
  background: var(--ink);
  color: var(--on-dark);
  text-decoration: none;
  border-radius: var(--radius);
  border-left: 3px solid var(--crimson);
  transition: transform 0.18s ease, background-color 0.18s ease;
}

.page-about .about-way:hover {
  transform: translateY(-2px);
  background: var(--ink-soft);
}

.page-about .about-way__k {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--gold);
}

.page-about .about-way h3 {
  margin: 10px 0 8px;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: 22px;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-way p {
  margin: 0 0 14px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--on-dark-dim);
}

.page-about .about-way__go {
  display: inline-block;
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--gold);
}

/* ---------- 右侧档案卡 ---------- */
.page-about .about-files {
  min-width: 0;
}

.page-about .about-files__head {
  margin: 0 0 16px;
  color: var(--slate);
}

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

.page-about .about-file {
  --shift: 0px;
  width: calc(100% - var(--about-shift));
  transform: translateX(var(--shift));
  transition: transform 0.2s ease;
}

.page-about .about-file__link {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  grid-template-areas:
    "num title arrow"
    "num note note";
  gap: 4px 14px;
  align-items: start;
  padding: 16px 18px;
  background: var(--white);
  border: 1px solid var(--line);
  border-left: 3px solid var(--gold);
  border-radius: var(--radius);
  box-shadow: 0 3px 0 -1px var(--sand);
  text-decoration: none;
  transition: box-shadow 0.18s ease, border-left-color 0.18s ease, transform 0.18s ease;
}

.page-about .about-file__link:hover {
  transform: translateY(-2px);
  border-left-color: var(--crimson);
  box-shadow: 0 6px 0 -2px var(--sand);
}

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

.page-about .about-file__num {
  grid-area: num;
  padding-top: 3px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--gold);
}

.page-about .about-file__title {
  grid-area: title;
  font-size: 16px;
  font-weight: 500;
  letter-spacing: 0.01em;
  color: var(--ink);
}

.page-about .about-file__arrow {
  grid-area: arrow;
  font-size: 13px;
  line-height: 1.6;
  color: var(--line);
  transition: color 0.18s ease;
}

.page-about .about-file__link:hover .about-file__arrow {
  color: var(--crimson);
}

.page-about .about-file__note {
  grid-area: note;
  font-size: 13px;
  line-height: 1.72;
  color: var(--slate);
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-team {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

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

@media (min-width: 960px) {
  .page-about .about-masthead {
    grid-template-columns: minmax(0, 1.28fr) minmax(0, 0.86fr);
    align-items: end;
    gap: clamp(32px, 4vw, 56px);
  }

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

@media (min-width: 1024px) {
  .page-about .about-split {
    grid-template-columns: minmax(0, 42fr) minmax(0, 58fr);
    gap: clamp(40px, 5vw, 74px);
  }

  .page-about .about-chapter .prose p,
  .page-about .about-node p,
  .page-about .about-flow p,
  .page-about .about-flow__lead {
    max-width: 34em;
  }

  .page-about .about-file:nth-child(1) { --shift: 0px; }
  .page-about .about-file:nth-child(2) { --shift: calc(var(--about-shift) * 0.6); }
  .page-about .about-file:nth-child(3) { --shift: var(--about-shift); }
  .page-about .about-file:nth-child(4) { --shift: calc(var(--about-shift) * 0.6); }
  .page-about .about-file:nth-child(5) { --shift: var(--about-shift); }
  .page-about .about-file:nth-child(6) { --shift: calc(var(--about-shift) * 0.6); }
  .page-about .about-file:nth-child(7) { --shift: 0px; }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-file,
  .page-about .about-file__link,
  .page-about .about-way,
  .page-about .about-node__note,
  .page-about .about-node::before,
  .page-about .chapter-index--bar a {
    transition: none;
  }

  .page-about .about-file__link:hover,
  .page-about .about-way:hover {
    transform: none;
  }
}