.page-about {
  --ab-col: 210px;
  background:
    radial-gradient(90% 46% at 6% 0%, rgba(232, 178, 58, .10), transparent 62%),
    var(--ink);
  color: var(--cream);
  font-family: var(--font-body);
  overflow-x: clip;
}

.page-about img,
.page-about svg {
  max-width: 100%;
}

/* ---------- 首屏 ---------- */

.page-about .ab-hero {
  position: relative;
  padding: 116px 0 56px;
  border-bottom: 1px solid var(--line);
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  inset: 96px 10px 18px;
  border: 1px solid rgba(110, 90, 46, .5);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 26px), calc(100% - 26px) 100%, 0 100%);
  pointer-events: none;
}

.page-about .ab-hero-inner {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 18px;
}

.page-about .ab-crumbs {
  font-size: 13px;
  color: var(--muted);
}

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

.page-about .ab-hero h1 {
  margin: 0 0 20px;
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(2.2rem, 9.4vw, 5.2rem);
  line-height: 1.04;
  letter-spacing: .02em;
  color: var(--cream);
}

.page-about .ab-hero .lede {
  margin: 0;
  max-width: 36em;
  font-size: 1.06rem;
  line-height: 1.9;
  color: rgba(245, 231, 198, .82);
}

.page-about .ab-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

/* ---------- 主体骨架 ---------- */

.page-about .ab-shell {
  display: grid;
  gap: 28px;
  padding: 40px 0 0;
}

.page-about .ab-index {
  border-top: 1px solid var(--line);
  padding-top: 14px;
}

.page-about .ab-index-title {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .18em;
  color: var(--muted);
}

.page-about .ab-index-list {
  list-style: none;
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 4px;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .ab-index-list::-webkit-scrollbar {
  display: none;
}

.page-about .ab-index-list a {
  display: flex;
  gap: 8px;
  align-items: baseline;
  padding: 8px 13px;
  border: 1px solid rgba(110, 90, 46, .5);
  color: var(--muted);
  font-size: 14px;
  text-decoration: none;
  white-space: nowrap;
  transition: color .24s var(--ease), border-color .24s var(--ease);
}

.page-about .ab-index-list a b {
  font-family: var(--font-mono);
  font-weight: 500;
  font-size: 12px;
  color: var(--line);
}

.page-about .ab-index-list a:hover,
.page-about .ab-index-list a.is-active,
.page-about .ab-index-list a[aria-current="true"] {
  color: var(--gold);
  border-color: rgba(232, 178, 58, .7);
}

.page-about .ab-index-list a.is-active b,
.page-about .ab-index-list a[aria-current="true"] b {
  color: var(--gold);
}

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

/* ---------- 章节 ---------- */

.page-about .ab-sec {
  padding: 46px 0;
  border-top: 1px solid rgba(110, 90, 46, .34);
  scroll-margin-top: 96px;
}

.page-about .ab-sec:first-child {
  border-top: none;
  padding-top: 6px;
}

.page-about .ab-sec-head {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 10px 16px;
  align-items: end;
  margin-bottom: 24px;
}

.page-about .ab-sec-kicker {
  grid-column: 1 / -1;
  display: flex;
  gap: 10px;
  align-items: center;
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--muted);
}

.page-about .ab-sec-num {
  color: var(--gold);
}

.page-about .ab-sec-head h2 {
  grid-column: 1;
  margin: 0;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(1.55rem, 6.2vw, 2.6rem);
  line-height: 1.14;
  letter-spacing: .02em;
  color: var(--cream);
}

.page-about .ab-copy {
  grid-column: 2;
  align-self: end;
  justify-self: end;
  padding: 6px 10px;
  border: 1px solid rgba(110, 90, 46, .55);
  background: none;
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  cursor: pointer;
  transition: color .2s var(--ease), border-color .2s var(--ease);
}

.page-about .ab-copy:hover {
  color: var(--gold);
  border-color: var(--gold);
}

.page-about .ab-copy[data-copy-state="done"] {
  color: var(--ok);
  border-color: var(--ok);
}

.page-about .ab-sec-lede {
  margin: 0 0 28px;
  max-width: 34em;
  font-size: 1.02rem;
  line-height: 1.9;
  color: rgba(245, 231, 198, .8);
}

/* ---------- 错位双栏 ---------- */

.page-about .ab-split {
  display: grid;
  gap: 28px;
}

.page-about .ab-fig {
  margin: 0;
}

.page-about .ab-fig img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .ab-fig-narrow {
  max-width: 460px;
  margin: 34px auto 0;
}

.page-about .ab-fig-cap {
  margin-top: 12px;
  padding-left: 14px;
  border-left: 2px solid rgba(232, 178, 58, .5);
  font-size: 13px;
  line-height: 1.85;
  color: var(--muted);
}

/* ---------- 卡点 / 节奏条目 ---------- */

.page-about .ab-cases {
  list-style: none;
  display: grid;
  gap: 26px;
  margin: 0;
  padding: 0;
}

.page-about .ab-cases li {
  padding-left: 16px;
  border-left: 2px solid rgba(232, 178, 58, .45);
}

.page-about .ab-cases--plain li {
  border-left-color: rgba(201, 106, 30, .6);
}

.page-about .ab-case-tag {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--gold);
}

.page-about .ab-cases h3 {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1.12rem;
  letter-spacing: .02em;
  color: var(--cream);
}

.page-about .ab-cases p {
  margin: 0;
  font-size: .98rem;
  line-height: 1.88;
  color: rgba(245, 231, 198, .76);
}

/* ---------- 主题带 ---------- */

.page-about .ab-band {
  margin: 30px 0;
  color: var(--cream);
}

.page-about .ab-band-inner {
  padding: 30px 22px;
}

.page-about .ab-band-lead {
  margin: 0 0 20px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: .02em;
  color: var(--cream);
}

.page-about .ab-band-stats {
  list-style: none;
  display: grid;
  gap: 20px;
  margin: 0;
  padding: 0;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
}

.page-about .ab-band-stat b {
  display: block;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.85rem;
  line-height: 1.2;
  color: var(--gold);
}

.page-about .ab-band-stat span {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  line-height: 1.8;
  color: rgba(245, 231, 198, .72);
}

/* ---------- 步骤 ---------- */

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

.page-about .ab-steps li {
  position: relative;
  margin-left: 15px;
  padding: 0 0 28px 40px;
  border-left: 1px solid rgba(110, 90, 46, .55);
}

.page-about .ab-steps li:last-child {
  border-left-color: transparent;
  padding-bottom: 0;
}

.page-about .ab-steps .ab-step-no {
  position: absolute;
  left: -15px;
  top: 0;
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  background: var(--ink-2);
  border: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--gold);
  clip-path: polygon(0 0, 100% 0, 100% 68%, 68% 100%, 0 100%);
}

.page-about .ab-steps h3 {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1.2rem;
  letter-spacing: .02em;
  color: var(--cream);
}

.page-about .ab-steps p {
  margin: 0;
  max-width: 32em;
  font-size: .98rem;
  line-height: 1.88;
  color: rgba(245, 231, 198, .76);
}

/* ---------- 展开层 ---------- */

.page-about .ab-fold {
  margin-top: 30px;
  border: 1px solid rgba(110, 90, 46, .5);
  background: rgba(30, 25, 19, .72);
}

.page-about .ab-fold .fold-head {
  display: flex;
  gap: 12px;
  align-items: center;
  width: 100%;
  padding: 15px 16px;
  border: 0;
  background: none;
  color: var(--cream);
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: .02em;
  text-align: left;
  cursor: pointer;
}

.page-about .ab-fold-no {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--gold);
}

.page-about .ab-fold .fold-sign {
  margin-left: auto;
  color: var(--gold);
  font-family: var(--font-mono);
}

.page-about .ab-fold .fold-body {
  padding: 0 16px 16px;
}

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

.page-about .ab-fold-list li {
  padding: 8px 0 8px 22px;
  border-top: 1px solid rgba(110, 90, 46, .3);
  font-size: .94rem;
  line-height: 1.85;
  color: rgba(245, 231, 198, .78);
}

.page-about .ab-fold-list li:first-child {
  border-top: none;
}

.page-about .ab-fold-list b {
  color: var(--gold);
  font-weight: 700;
}

/* ---------- 团队角色 ---------- */

.page-about .ab-team {
  display: grid;
  gap: 18px;
}

.page-about .ab-role {
  padding: 6px 8px;
}

.page-about .ab-role .fold-head {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 4px 12px;
  align-items: baseline;
  width: 100%;
  padding: 14px 12px;
  border: 0;
  background: none;
  color: var(--cream);
  text-align: left;
  cursor: pointer;
}

.page-about .ab-role-no {
  grid-row: 1 / 3;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--gold);
}

.page-about .ab-role-name {
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1.08rem;
  letter-spacing: .02em;
}

.page-about .ab-role-count {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--muted);
}

.page-about .ab-role .fold-sign {
  grid-column: 2;
  justify-self: end;
  color: var(--gold);
  font-family: var(--font-mono);
}

.page-about .ab-role .fold-body {
  padding: 0 12px 14px 36px;
}

.page-about .ab-role .fold-body ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-role .fold-body li {
  position: relative;
  padding: 7px 0 7px 16px;
  font-size: .92rem;
  line-height: 1.85;
  color: rgba(245, 231, 198, .78);
}

.page-about .ab-role .fold-body li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 16px;
  width: 6px;
  height: 6px;
  background: var(--gold);
  transform: rotate(45deg);
}

/* ---------- 环形节奏 ---------- */

.page-about .ab-ring-wrap {
  display: grid;
  place-items: center;
  padding: 8px 0;
}

.page-about .ab-ring {
  width: 100%;
  max-width: 340px;
  height: auto;
}

/* ---------- 时间线 ---------- */

.page-about .ab-timeline {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .ab-timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 18px;
  width: 1px;
  background: linear-gradient(180deg, var(--gold), rgba(110, 90, 46, .18));
}

.page-about .ab-timeline li {
  position: relative;
  padding: 0 0 26px 34px;
}

.page-about .ab-timeline li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 6px;
  width: 15px;
  height: 15px;
  background: var(--ink);
  border: 1px solid var(--gold);
  transform: rotate(45deg);
}

.page-about .ab-year {
  margin: 0 0 4px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .14em;
  color: var(--gold);
}

.page-about .ab-year-note {
  margin-left: 10px;
  color: var(--muted);
  letter-spacing: .1em;
  transition: color .25s var(--ease);
}

.page-about .ab-timeline li:hover .ab-year-note {
  color: var(--amber);
}

.page-about .ab-timeline h3 {
  margin: 0 0 6px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1.06rem;
  letter-spacing: .02em;
  color: var(--cream);
}

.page-about .ab-timeline p {
  margin: 0;
  max-width: 34em;
  font-size: .96rem;
  line-height: 1.88;
  color: rgba(245, 231, 198, .74);
}

/* ---------- 结尾 ---------- */

.page-about .ab-next {
  padding: 12px 0 72px;
}

.page-about .ab-next-panel {
  padding: 28px 22px;
}

.page-about .ab-next-panel h2 {
  margin: 0 0 14px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(1.35rem, 5.4vw, 2rem);
  line-height: 1.2;
  letter-spacing: .02em;
  color: var(--cream);
}

.page-about .ab-next-panel p {
  margin: 0;
  max-width: 34em;
  font-size: .98rem;
  line-height: 1.9;
  color: rgba(245, 231, 198, .78);
}

.page-about .ab-next-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 24px 0 20px;
}

.page-about .ab-next-mail {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  padding-top: 18px;
  border-top: 1px solid rgba(110, 90, 46, .4);
  font-size: 13px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .ab-next-mail b {
  font-family: var(--font-mono);
  font-weight: 500;
  color: var(--cream);
}

/* ---------- 桌面端 ---------- */

@media (min-width: 900px) {
  .page-about .ab-hero {
    padding: 150px 0 78px;
  }

  .page-about .ab-hero::before {
    inset: 122px 26px 30px;
    border-color: rgba(110, 90, 46, .6);
  }

  .page-about .ab-hero-inner {
    grid-template-columns: 60px minmax(0, 1fr);
    gap: 26px;
    align-items: start;
  }

  .page-about .ab-crumbs {
    grid-column: 1 / -1;
  }

  .page-about .ab-hero-note {
    writing-mode: vertical-rl;
    text-orientation: mixed;
    justify-self: start;
    height: 220px;
    padding-top: 6px;
    letter-spacing: .24em;
  }

  .page-about .ab-split {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: 52px;
    align-items: start;
  }

  .page-about .ab-split--drop > :last-child {
    margin-top: 58px;
  }

  .page-about .ab-sec {
    padding: 60px 0;
  }

  .page-about .ab-band-inner {
    padding: 36px 30px;
  }

  .page-about .ab-team {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
    align-items: start;
  }

  .page-about .ab-team > :nth-child(2) {
    margin-top: 32px;
  }

  .page-about .ab-team > :nth-child(3) {
    margin-top: 64px;
  }

  .page-about .ab-next-panel {
    padding: 40px 44px;
  }
}

@media (min-width: 1024px) {
  .page-about .ab-shell {
    grid-template-columns: var(--ab-col) minmax(0, 1fr);
    gap: 60px;
    align-items: start;
    padding-top: 56px;
  }

  .page-about .ab-index {
    position: sticky;
    top: 96px;
  }

  .page-about .ab-index-list {
    display: block;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .ab-index-list li + li {
    margin-top: 2px;
  }

  .page-about .ab-index-list a {
    border: none;
    border-left: 2px solid transparent;
    padding: 8px 0 8px 12px;
    white-space: normal;
    font-size: 15px;
    line-height: 1.5;
  }

  .page-about .ab-index-list a.is-active,
  .page-about .ab-index-list a[aria-current="true"] {
    border-left-color: var(--gold);
    background: linear-gradient(90deg, rgba(232, 178, 58, .12), transparent 72%);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-index-list a,
  .page-about .ab-copy,
  .page-about .ab-year-note {
    transition: none;
  }
}