.page-about {
  --ab-line: rgba(8, 23, 37, .12);
  --ab-line-strong: rgba(8, 23, 37, .2);
  --ab-line-light: rgba(217, 226, 232, .16);
  --ab-gap: clamp(1.4rem, 3.6vw, 2.4rem);
  background: var(--paper);
  color: var(--ink-900);
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.85;
  overflow-x: hidden;
}

.page-about *,
.page-about *::before,
.page-about *::after {
  box-sizing: border-box;
}

.page-about h1,
.page-about h2,
.page-about h3 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  letter-spacing: .04em;
}

.page-about p {
  margin: 0 0 1em;
  max-width: 36em;
}

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

.page-about ul,
.page-about ol,
.page-about dl {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about a {
  color: inherit;
}

.page-about .inline-link {
  color: var(--copper);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}

.page-about .inline-link:hover,
.page-about .inline-link:focus-visible {
  color: var(--wine);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(1rem, 3vw, 1.6rem) 0 clamp(2.4rem, 6vw, 4.4rem);
  color: var(--paper);
  background:
    radial-gradient(110% 85% at 92% -5%, rgba(39, 76, 94, .85), rgba(8, 23, 37, 0) 62%),
    linear-gradient(166deg, var(--ink-900) 0%, var(--ink-800) 44%, var(--ink-700) 100%);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 22px;
  background-image: repeating-linear-gradient(90deg, rgba(215, 166, 74, .55) 0 1px, transparent 1px 20px);
  opacity: .45;
  pointer-events: none;
}

.page-about .about-crumb {
  position: relative;
  z-index: 2;
}

.page-about .about-crumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: .45rem;
  font-family: var(--font-mono);
  font-size: .76rem;
  letter-spacing: .08em;
  color: rgba(245, 241, 232, .62);
}

.page-about .about-crumb li:not(:first-child)::before {
  content: "/";
  margin-right: .45rem;
  color: rgba(215, 166, 74, .72);
}

.page-about .about-crumb a {
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .2s ease, border-color .2s ease;
}

.page-about .about-crumb a:hover,
.page-about .about-crumb a:focus-visible {
  color: var(--paper);
  border-bottom-color: var(--amber);
}

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

.page-about .about-hero__grid {
  position: relative;
  z-index: 2;
  display: grid;
  gap: clamp(1.6rem, 4vw, 2.6rem);
  margin-top: clamp(1.8rem, 5vw, 3rem);
}

.page-about .about-hero__eyebrow {
  font-family: var(--font-mono);
  font-size: .76rem;
  letter-spacing: .22em;
  color: var(--amber);
  margin-bottom: .7rem;
}

.page-about .about-hero h1 {
  font-size: clamp(2rem, 7.4vw, 3.6rem);
  line-height: 1.16;
  letter-spacing: .02em;
  max-width: 12em;
  margin-bottom: 1.1rem;
  color: var(--paper);
}

.page-about .about-hero__lead {
  font-size: clamp(.98rem, 2.4vw, 1.06rem);
  line-height: 1.9;
  color: rgba(245, 241, 232, .84);
  max-width: 34em;
}

.page-about .about-hero__lead--sub {
  color: rgba(217, 226, 232, .70);
  font-size: .95rem;
  padding-left: .9rem;
  border-left: 2px solid rgba(215, 166, 74, .55);
}

.page-about .about-facts {
  border: 1px solid var(--ab-line-light);
  border-radius: var(--radius);
  padding: 1.1rem 1.15rem 1.2rem;
  background: linear-gradient(158deg, rgba(245, 241, 232, .08), rgba(245, 241, 232, .02));
}

.page-about .about-facts__title {
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .2em;
  color: var(--amber);
  margin: 0 0 .9rem;
  max-width: none;
}

.page-about .about-facts dl {
  display: grid;
  gap: .62rem;
}

.page-about .about-facts dl > div {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  padding-bottom: .55rem;
  border-bottom: 1px dashed rgba(217, 226, 232, .18);
}

.page-about .about-facts dl > div:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .about-facts dt {
  font-size: .8rem;
  color: rgba(217, 226, 232, .72);
}

.page-about .about-facts dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: .9rem;
  letter-spacing: .03em;
  color: var(--paper);
  white-space: nowrap;
}

/* ---------- 主体栅格 ---------- */
.page-about .about-body {
  display: grid;
  gap: var(--ab-gap);
  padding: clamp(1.8rem, 5vw, 3.4rem) 0 clamp(2.6rem, 6vw, 4.4rem);
}

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

.page-about .about-toc__title {
  display: none;
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .2em;
  color: var(--steel);
  margin-bottom: .85rem;
  max-width: none;
}

.page-about .about-toc nav {
  display: flex;
  gap: .5rem;
  overflow-x: auto;
  padding-bottom: .35rem;
  scrollbar-width: thin;
}

.page-about .toc-link {
  flex: none;
  white-space: nowrap;
  display: block;
  padding: .34rem .8rem;
  font-size: .86rem;
  color: var(--steel);
  text-decoration: none;
  border: 1px solid var(--ab-line);
  border-radius: 999px;
  transition: background-color .2s ease, color .2s ease, border-color .2s ease;
}

.page-about .toc-link:hover,
.page-about .toc-link:focus-visible {
  color: var(--ink-900);
  border-color: var(--copper);
}

.page-about .toc-link.is-active {
  background: var(--ink-900);
  color: var(--paper);
  border-color: var(--ink-900);
}

.page-about .about-flow {
  display: grid;
  gap: var(--ab-gap);
  min-width: 0;
}

/* ---------- 章节通用 ---------- */
.page-about .about-section {
  position: relative;
  min-width: 0;
  padding: clamp(1.3rem, 3.4vw, 2.3rem);
  border-radius: calc(var(--radius) + 6px);
  border: 1px solid var(--ab-line);
  background: #FBF8F1;
  overflow: hidden;
}

.page-about .about-section--dark {
  border-color: rgba(217, 226, 232, .16);
  color: var(--paper);
  background:
    radial-gradient(100% 90% at 88% 0%, rgba(39, 76, 94, .55), rgba(8, 23, 37, 0) 60%),
    linear-gradient(168deg, var(--ink-900), var(--ink-700));
}

.page-about .about-section--team {
  background: linear-gradient(170deg, rgba(217, 226, 232, .55), rgba(245, 241, 232, .9));
}

.page-about .about-section--standard {
  border-top: 4px solid var(--build);
}

.page-about .about-section--next {
  border-top: 4px solid var(--amber);
}

.page-about .sec-head {
  display: flex;
  align-items: baseline;
  gap: .8rem;
  margin-bottom: 1.1rem;
  padding-bottom: .8rem;
  border-bottom: 1px solid var(--ab-line);
}

.page-about .about-section--dark .sec-head {
  border-bottom-color: rgba(217, 226, 232, .2);
}

.page-about .sec-num {
  flex: none;
  margin: 0;
  max-width: none;
  font-family: var(--font-mono);
  font-size: .76rem;
  letter-spacing: .16em;
  color: var(--copper);
}

.page-about .about-section--dark .sec-num {
  color: var(--amber);
}

.page-about .sec-title {
  font-size: clamp(1.24rem, 3.6vw, 1.85rem);
  line-height: 1.36;
  letter-spacing: .02em;
}

.page-about .about-section p {
  font-size: .98rem;
}

.page-about .about-section--dark p {
  color: rgba(245, 241, 232, .84);
}

.page-about .split {
  display: grid;
  gap: clamp(1.1rem, 3vw, 1.7rem);
}

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

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

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

.page-about .about-figure figcaption {
  margin-top: .6rem;
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .05em;
  color: var(--steel);
  line-height: 1.6;
}

/* ---------- 时间轴 ---------- */
.page-about .about-section--dark > .tl-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  margin: 0;
  opacity: .18;
  pointer-events: none;
}

.page-about .tl-bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.page-about .about-section--dark > .sec-head,
.page-about .about-section--dark > .tl,
.page-about .about-section--dark > .tl-intro,
.page-about .about-section--dark > .scale-intro,
.page-about .about-section--dark > .scale-foot,
.page-about .about-section--dark > .stat-grid,
.page-about .about-section--dark > .next-list,
.page-about .about-section--dark > .next-note,
.page-about .about-section--dark > .cta-row {
  position: relative;
  z-index: 1;
}

.page-about .tl-intro {
  font-size: .93rem !important;
  color: rgba(217, 226, 232, .76) !important;
  margin-bottom: 1.3rem;
}

.page-about .tl {
  position: relative;
}

.page-about .tl::before {
  content: "";
  position: absolute;
  left: 9px;
  top: .5rem;
  bottom: .5rem;
  width: 2px;
  background: linear-gradient(180deg, rgba(215, 166, 74, .9), rgba(215, 166, 74, .12));
}

.page-about .tl-item {
  position: relative;
  padding-left: 38px;
}

.page-about .tl-item + .tl-item {
  margin-top: .8rem;
}

.page-about .tl-item::before {
  content: "";
  position: absolute;
  left: 3px;
  top: 1.02rem;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--ink-900);
  border: 2px solid var(--steel);
}

.page-about .tl-item--now::before {
  background: var(--amber);
  border-color: var(--amber);
  box-shadow: 0 0 0 6px rgba(215, 166, 74, .16);
}

.page-about .tl-details {
  border: 1px solid rgba(217, 226, 232, .18);
  border-radius: var(--radius-sm);
  background: rgba(245, 241, 232, .05);
  transition: border-color .22s ease, background-color .22s ease;
}

.page-about .tl-details[open] {
  border-color: rgba(215, 166, 74, .48);
  background: rgba(245, 241, 232, .09);
}

.page-about .tl-details summary {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: baseline;
  gap: .7rem;
  padding: .8rem 1rem;
  cursor: pointer;
  list-style: none;
}

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

.page-about .tl-details summary:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

.page-about .tl-year {
  font-family: var(--font-mono);
  font-size: .94rem;
  letter-spacing: .06em;
  color: var(--amber);
}

.page-about .tl-title {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 600;
  color: var(--paper);
  line-height: 1.5;
}

.page-about .tl-mark {
  position: relative;
  width: 12px;
  height: 12px;
  flex: none;
  transform: translateY(1px);
}

.page-about .tl-mark::before,
.page-about .tl-mark::after {
  content: "";
  position: absolute;
  background: var(--amber);
  transition: opacity .2s ease;
}

.page-about .tl-mark::before {
  left: 0;
  top: 5px;
  width: 12px;
  height: 2px;
}

.page-about .tl-mark::after {
  left: 5px;
  top: 0;
  width: 2px;
  height: 12px;
}

.page-about .tl-details[open] .tl-mark::after {
  opacity: 0;
}

.page-about .tl-body {
  padding: .8rem 1rem .95rem;
  border-top: 1px dashed rgba(217, 226, 232, .2);
}

.page-about .tl-body p {
  font-size: .92rem;
  color: rgba(245, 241, 232, .82);
  max-width: 38em;
}

/* ---------- 团队 ---------- */
.page-about .role-list {
  display: grid;
  gap: .65rem;
  margin: 1rem 0;
}

.page-about .role-list li {
  padding: .7rem .9rem;
  border-radius: var(--radius-sm);
  background: rgba(21, 69, 63, .07);
  border-left: 3px solid var(--build);
}

.page-about .role-list strong {
  display: block;
  font-size: .93rem;
  color: var(--build);
  margin-bottom: .1rem;
  letter-spacing: .02em;
}

.page-about .role-list span {
  font-size: .85rem;
  color: var(--steel);
  line-height: 1.7;
}

/* ---------- 编号规则 ---------- */
.page-about .specimen {
  margin: 1rem 0 1.2rem;
  padding: 1rem 1.05rem 1.1rem;
  border-radius: var(--radius);
  background: linear-gradient(150deg, rgba(21, 69, 63, .1), rgba(21, 69, 63, .03));
  border: 1px dashed rgba(21, 69, 63, .38);
}

.page-about .specimen__label {
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .2em;
  color: var(--steel);
  margin: 0 0 .35rem;
  max-width: none;
}

.page-about .specimen__code {
  font-family: var(--font-mono);
  font-size: clamp(1.7rem, 7vw, 2.5rem);
  letter-spacing: .1em;
  line-height: 1.2;
  color: var(--build);
  margin: 0 0 .9rem;
  max-width: none;
  word-break: break-all;
}

.page-about .specimen__parts {
  display: grid;
  gap: .6rem;
}

.page-about .specimen__parts > div {
  padding-top: .45rem;
  border-top: 2px solid var(--copper);
}

.page-about .specimen__parts dt {
  font-family: var(--font-mono);
  font-size: .68rem;
  letter-spacing: .14em;
  color: var(--steel);
}

.page-about .specimen__parts dd {
  margin: .18rem 0 0;
  font-size: .86rem;
  font-weight: 600;
  color: var(--ink-900);
}

.page-about .field-list {
  display: grid;
  gap: .1rem;
  margin: .9rem 0;
}

.page-about .field-list li {
  display: grid;
  grid-template-columns: 2rem 1fr;
  gap: .55rem;
  align-items: baseline;
  padding: .55rem 0;
  border-bottom: 1px solid rgba(8, 23, 37, .08);
}

.page-about .field-list li:last-child {
  border-bottom: 0;
}

.page-about .field-list .fnum {
  font-family: var(--font-mono);
  font-size: .76rem;
  color: var(--copper);
}

.page-about .field-list .ftext {
  font-size: .93rem;
  line-height: 1.75;
}

.page-about .field-list strong {
  color: var(--build);
}

.page-about .standard-note {
  font-size: .9rem !important;
  color: var(--steel);
  padding-left: .85rem;
  border-left: 3px solid var(--amber);
}

/* ---------- 支持分档 ---------- */
.page-about .tier {
  margin-top: .75rem;
  padding: .95rem 1.05rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--ab-line);
  border-left-width: 4px;
  border-left-style: solid;
  background: #fff;
}

.page-about .tier--current {
  border-left-color: var(--build);
}

.page-about .tier--prev {
  border-left-color: var(--steel);
}

.page-about .tier--old {
  border-left-color: var(--wine);
}

.page-about .tier__tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .12em;
  color: var(--steel);
  margin: 0 0 .3rem;
}

.page-about .tier__title {
  font-size: 1.06rem;
  margin-bottom: .25rem;
  color: var(--ink-900);
}

.page-about .tier p {
  font-size: .92rem;
  color: var(--ink-700);
}

.page-about .support-note {
  margin-top: 1rem !important;
  font-size: .92rem !important;
  color: var(--steel);
}

/* ---------- 规模 ---------- */
.page-about .scale-intro {
  font-size: .94rem !important;
  color: rgba(217, 226, 232, .78) !important;
  margin-bottom: 1.1rem;
}

.page-about .stat-grid {
  display: grid;
  gap: .7rem;
}

.page-about .stat {
  padding: .9rem 1rem;
  border-radius: var(--radius-sm);
  background: rgba(245, 241, 232, .06);
  border: 1px solid rgba(217, 226, 232, .15);
}

.page-about .stat__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1.4rem, 4.6vw, 1.95rem);
  letter-spacing: .02em;
  line-height: 1.2;
  color: var(--amber);
}

.page-about .stat__label {
  display: block;
  margin-top: .2rem;
  font-size: .86rem;
  color: rgba(245, 241, 232, .88);
}

.page-about .stat__note {
  display: block;
  margin-top: .28rem;
  font-size: .76rem;
  line-height: 1.6;
  color: rgba(217, 226, 232, .6);
}

.page-about .scale-foot {
  margin-top: 1.1rem !important;
  font-size: .9rem !important;
  color: rgba(217, 226, 232, .78) !important;
}

/* ---------- 后续计划 ---------- */
.page-about .next-list {
  display: grid;
  gap: .7rem;
}

.page-about .next-card {
  padding: .95rem 1.05rem;
  border-radius: var(--radius-sm);
  background: rgba(215, 166, 74, .12);
  border: 1px solid rgba(215, 166, 74, .38);
}

.page-about .next-card__title {
  font-size: 1.02rem;
  margin-bottom: .25rem;
  color: var(--amber);
}

.page-about .next-card p {
  font-size: .9rem;
  color: rgba(245, 241, 232, .84);
}

.page-about .next-note {
  margin-top: 1rem !important;
  font-size: .92rem !important;
  color: rgba(245, 241, 232, .82) !important;
}

.page-about .cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: .55rem;
  margin-top: 1.2rem;
}

.page-about .cta-row .btn {
  text-decoration: none;
  font-size: .9rem;
}

.page-about .cta-row .btn:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 3px;
}

/* ---------- 断点 ---------- */
@media (min-width: 560px) {
  .page-about .stat-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

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

@media (min-width: 780px) {
  .page-about .split {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, .95fr);
    align-items: start;
  }

  .page-about .split--rev > .split__media {
    order: 2;
  }

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

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.45fr) minmax(0, .75fr);
    align-items: end;
  }

  .page-about .stat-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

@media (min-width: 960px) {
  .page-about .about-body {
    grid-template-columns: 190px minmax(0, 1fr);
    align-items: start;
    gap: clamp(2rem, 4vw, 3.4rem);
  }

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

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

  .page-about .about-toc nav {
    display: block;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .toc-link {
    border: 0;
    border-radius: 0;
    border-left: 2px solid var(--ab-line);
    padding: .38rem 0 .38rem .8rem;
    font-size: .88rem;
    white-space: normal;
  }

  .page-about .toc-link.is-active {
    background: transparent;
    color: var(--ink-900);
    border-left-color: var(--amber);
    font-weight: 600;
  }

  .page-about .about-section {
    padding: clamp(1.6rem, 3vw, 2.5rem);
  }
}

@media (min-width: 1100px) {
  .page-about .about-rotate {
    display: block;
    position: absolute;
    right: 20px;
    top: 30%;
    z-index: 1;
    writing-mode: vertical-rl;
    margin: 0;
    max-width: none;
    font-family: var(--font-mono);
    font-size: .72rem;
    letter-spacing: .42em;
    color: rgba(215, 166, 74, .78);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .toc-link,
  .page-about .tl-details,
  .page-about .tl-mark::after,
  .page-about .about-crumb a {
    transition: none;
  }
}

.page-about {
  --ab-line: rgba(8, 23, 37, .12);
  --ab-line-light: rgba(217, 226, 232, .16);
  --ab-gap: clamp(1.4rem, 3.6vw, 2.4rem);
  background: var(--paper);
  color: var(--ink-900);
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.85;
  overflow-x: hidden;
}

.page-about *,
.page-about *::before,
.page-about *::after {
  box-sizing: border-box;
}

.page-about h1,
.page-about h2,
.page-about h3 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  letter-spacing: .04em;
}

.page-about p {
  margin: 0 0 1em;
  max-width: 36em;
}

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

.page-about ul,
.page-about ol,
.page-about dl {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about a {
  color: inherit;
}

.page-about .inline-link {
  color: var(--copper);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}

.page-about .inline-link:hover,
.page-about .inline-link:focus-visible {
  color: var(--wine);
}

/* 首屏 */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(1rem, 3vw, 1.6rem) 0 clamp(2.4rem, 6vw, 4.4rem);
  color: var(--paper);
  background:
    radial-gradient(110% 85% at 92% -5%, rgba(39, 76, 94, .85), rgba(8, 23, 37, 0) 62%),
    linear-gradient(166deg, var(--ink-900) 0%, var(--ink-800) 44%, var(--ink-700) 100%);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 22px;
  background-image: repeating-linear-gradient(90deg, rgba(215, 166, 74, .55) 0 1px, transparent 1px 20px);
  opacity: .45;
  pointer-events: none;
}

.page-about .about-crumb {
  position: relative;
  z-index: 2;
}

.page-about .about-crumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: .45rem;
  font-family: var(--font-mono);
  font-size: .76rem;
  letter-spacing: .08em;
  color: rgba(245, 241, 232, .62);
}

.page-about .about-crumb li:not(:first-child)::before {
  content: "/";
  margin-right: .45rem;
  color: rgba(215, 166, 74, .72);
}

.page-about .about-crumb a {
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .2s ease, border-color .2s ease;
}

.page-about .about-crumb a:hover,
.page-about .about-crumb a:focus-visible {
  color: var(--paper);
  border-bottom-color: var(--amber);
}

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

.page-about .about-hero__grid {
  position: relative;
  z-index: 2;
  display: grid;
  gap: clamp(1.6rem, 4vw, 2.6rem);
  margin-top: clamp(1.8rem, 5vw, 3rem);
}

.page-about .about-hero__eyebrow {
  font-family: var(--font-mono);
  font-size: .76rem;
  letter-spacing: .22em;
  color: var(--amber);
  margin-bottom: .7rem;
  max-width: none;
}

.page-about .about-hero h1 {
  font-size: clamp(2rem, 7.4vw, 3.6rem);
  line-height: 1.16;
  letter-spacing: .02em;
  max-width: 12em;
  margin-bottom: 1.1rem;
  color: var(--paper);
}

.page-about .about-hero__lead {
  font-size: clamp(.98rem, 2.4vw, 1.06rem);
  line-height: 1.9;
  color: rgba(245, 241, 232, .84);
  max-width: 34em;
}

.page-about .about-hero__lead--sub {
  color: rgba(217, 226, 232, .7);
  font-size: .95rem;
  padding-left: .9rem;
  border-left: 2px solid rgba(215, 166, 74, .55);
}

.page-about .about-facts {
  border: 1px solid var(--ab-line-light);
  border-radius: var(--radius);
  padding: 1.1rem 1.15rem 1.2rem;
  background: linear-gradient(158deg, rgba(245, 241, 232, .08), rgba(245, 241, 232, .02));
}

.page-about .about-facts__title {
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .2em;
  color: var(--amber);
  margin: 0 0 .9rem;
  max-width: none;
}

.page-about .about-facts dl {
  display: grid;
  gap: .62rem;
}

.page-about .about-facts dl > div {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  padding-bottom: .55rem;
  border-bottom: 1px dashed rgba(217, 226, 232, .18);
}

.page-about .about-facts dl > div:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .about-facts dt {
  font-size: .8rem;
  color: rgba(217, 226, 232, .72);
}

.page-about .about-facts dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: .9rem;
  letter-spacing: .03em;
  color: var(--paper);
  white-space: nowrap;
}

/* 主体栅格与章节目录 */
.page-about .about-body {
  display: grid;
  gap: var(--ab-gap);
  padding: clamp(1.8rem, 5vw, 3.4rem) 0 clamp(2.6rem, 6vw, 4.4rem);
}

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

.page-about .about-toc__title {
  display: none;
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .2em;
  color: var(--steel);
  margin-bottom: .85rem;
  max-width: none;
}

.page-about .about-toc nav {
  display: flex;
  gap: .5rem;
  overflow-x: auto;
  padding-bottom: .35rem;
}

.page-about .toc-link {
  flex: none;
  white-space: nowrap;
  display: block;
  padding: .34rem .8rem;
  font-size: .86rem;
  color: var(--steel);
  text-decoration: none;
  border: 1px solid var(--ab-line);
  border-radius: 999px;
  transition: background-color .2s ease, color .2s ease, border-color .2s ease;
}

.page-about .toc-link:hover {
  color: var(--ink-900);
  border-color: var(--copper);
}

.page-about .toc-link:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 2px;
  color: var(--ink-900);
}

.page-about .toc-link.is-active {
  background: var(--ink-900);
  color: var(--paper);
  border-color: var(--ink-900);
}

.page-about .about-flow {
  display: grid;
  gap: var(--ab-gap);
  min-width: 0;
}

/* 章节通用 */
.page-about .about-section {
  position: relative;
  min-width: 0;
  padding: clamp(1.3rem, 3.4vw, 2.3rem);
  border-radius: calc(var(--radius) + 6px);
  border: 1px solid var(--ab-line);
  background: #FBF8F1;
  overflow: hidden;
}

.page-about .about-section--dark {
  border-color: rgba(217, 226, 232, .16);
  color: var(--paper);
  background:
    radial-gradient(100% 90% at 88% 0%, rgba(39, 76, 94, .55), rgba(8, 23, 37, 0) 60%),
    linear-gradient(168deg, var(--ink-900), var(--ink-700));
}

.page-about .about-section--team {
  background: linear-gradient(170deg, rgba(217, 226, 232, .55), rgba(245, 241, 232, .92));
}

.page-about .about-section--standard {
  border-top: 4px solid var(--build);
}

.page-about .about-section--next {
  border-top: 4px solid var(--amber);
}

.page-about .sec-head {
  display: flex;
  align-items: baseline;
  gap: .8rem;
  margin-bottom: 1.1rem;
  padding-bottom: .8rem;
  border-bottom: 1px solid var(--ab-line);
}

.page-about .about-section--dark .sec-head {
  border-bottom-color: rgba(217, 226, 232, .2);
}

.page-about .sec-num {
  flex: none;
  margin: 0;
  max-width: none;
  font-family: var(--font-mono);
  font-size: .76rem;
  letter-spacing: .16em;
  color: var(--copper);
}

.page-about .about-section--dark .sec-num {
  color: var(--amber);
}

.page-about .sec-title {
  font-size: clamp(1.24rem, 3.6vw, 1.85rem);
  line-height: 1.36;
  letter-spacing: .02em;
}

.page-about .about-section p {
  font-size: .98rem;
}

.page-about .about-section--dark p {
  color: rgba(245, 241, 232, .84);
}

.page-about .split {
  display: grid;
  gap: clamp(1.1rem, 3vw, 1.7rem);
}

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

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

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

.page-about .about-figure figcaption {
  margin-top: .6rem;
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .05em;
  color: var(--steel);
  line-height: 1.6;
}

/* 时间轴 */
.page-about .about-section--dark > .tl-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  margin: 0;
  opacity: .18;
  pointer-events: none;
}

.page-about .tl-bg img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.page-about .about-section--dark > .sec-head,
.page-about .about-section--dark > .tl,
.page-about .about-section--dark > .tl-intro,
.page-about .about-section--dark > .scale-intro,
.page-about .about-section--dark > .scale-foot,
.page-about .about-section--dark > .stat-grid,
.page-about .about-section--dark > .next-list,
.page-about .about-section--dark > .next-note,
.page-about .about-section--dark > .cta-row {
  position: relative;
  z-index: 1;
}

.page-about .tl-intro {
  font-size: .93rem !important;
  color: rgba(217, 226, 232, .76) !important;
  margin-bottom: 1.3rem;
}

.page-about .tl {
  position: relative;
}

.page-about .tl::before {
  content: "";
  position: absolute;
  left: 9px;
  top: .5rem;
  bottom: .5rem;
  width: 2px;
  background: linear-gradient(180deg, rgba(215, 166, 74, .9), rgba(215, 166, 74, .12));
}

.page-about .tl-item {
  position: relative;
  padding-left: 38px;
}

.page-about .tl-item + .tl-item {
  margin-top: .8rem;
}

.page-about .tl-item::before {
  content: "";
  position: absolute;
  left: 3px;
  top: 1.02rem;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--ink-900);
  border: 2px solid var(--steel);
}

.page-about .tl-item--now::before {
  background: var(--amber);
  border-color: var(--amber);
  box-shadow: 0 0 0 6px rgba(215, 166, 74, .16);
}

.page-about .tl-details {
  border: 1px solid rgba(217, 226, 232, .18);
  border-radius: var(--radius-sm);
  background: rgba(245, 241, 232, .05);
  transition: border-color .22s ease, background-color .22s ease;
}

.page-about .tl-details[open] {
  border-color: rgba(215, 166, 74, .48);
  background: rgba(245, 241, 232, .09);
}

.page-about .tl-details summary {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: baseline;
  gap: .7rem;
  padding: .8rem 1rem;
  cursor: pointer;
  list-style: none;
}

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

.page-about .tl-details summary:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

.page-about .tl-year {
  font-family: var(--font-mono);
  font-size: .94rem;
  letter-spacing: .06em;
  color: var(--amber);
}

.page-about .tl-title {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 600;
  line-height: 1.5;
  color: var(--paper);
}

.page-about .tl-mark {
  position: relative;
  flex: none;
  width: 12px;
  height: 12px;
  transform: translateY(1px);
}

.page-about .tl-mark::before,
.page-about .tl-mark::after {
  content: "";
  position: absolute;
  background: var(--amber);
  transition: opacity .2s ease;
}

.page-about .tl-mark::before {
  left: 0;
  top: 5px;
  width: 12px;
  height: 2px;
}

.page-about .tl-mark::after {
  left: 5px;
  top: 0;
  width: 2px;
  height: 12px;
}

.page-about .tl-details[open] .tl-mark::after {
  opacity: 0;
}

.page-about .tl-body {
  padding: .8rem 1rem .95rem;
  border-top: 1px dashed rgba(217, 226, 232, .2);
}

.page-about .tl-body p {
  font-size: .92rem;
  color: rgba(245, 241, 232, .82);
  max-width: 38em;
}

/* 团队 */
.page-about .role-list {
  display: grid;
  gap: .65rem;
  margin: 1rem 0;
}

.page-about .role-list li {
  padding: .7rem .9rem;
  border-radius: var(--radius-sm);
  background: rgba(21, 69, 63, .07);
  border-left: 3px solid var(--build);
}

.page-about .role-list strong {
  display: block;
  font-size: .93rem;
  color: var(--build);
  margin-bottom: .1rem;
  letter-spacing: .02em;
}

.page-about .role-list span {
  font-size: .85rem;
  color: var(--steel);
  line-height: 1.7;
}

/* 编号规则 */
.page-about .specimen {
  margin: 1rem 0 1.2rem;
  padding: 1rem 1.05rem 1.1rem;
  border-radius: var(--radius);
  background: linear-gradient(150deg, rgba(21, 69, 63, .1), rgba(21, 69, 63, .03));
  border: 1px dashed rgba(21, 69, 63, .38);
}

.page-about .specimen__label {
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .2em;
  color: var(--steel);
  margin: 0 0 .35rem;
  max-width: none;
}

.page-about .specimen__code {
  font-family: var(--font-mono);
  font-size: clamp(1.7rem, 7vw, 2.5rem);
  letter-spacing: .1em;
  line-height: 1.2;
  color: var(--build);
  margin: 0 0 .9rem;
  max-width: none;
  word-break: break-all;
}

.page-about .specimen__parts {
  display: grid;
  gap: .6rem;
}

.page-about .specimen__parts > div {
  padding-top: .45rem;
  border-top: 2px solid var(--copper);
}

.page-about .specimen__parts dt {
  font-family: var(--font-mono);
  font-size: .68rem;
  letter-spacing: .14em;
  color: var(--steel);
}

.page-about .specimen__parts dd {
  margin: .18rem 0 0;
  font-size: .86rem;
  font-weight: 600;
  color: var(--ink-900);
}

.page-about .field-list {
  display: grid;
  gap: .1rem;
  margin: .9rem 0;
}

.page-about .field-list li {
  display: grid;
  grid-template-columns: 2rem minmax(0, 1fr);
  gap: .55rem;
  align-items: baseline;
  padding: .55rem 0;
  border-bottom: 1px solid rgba(8, 23, 37, .08);
}

.page-about .field-list li:last-child {
  border-bottom: 0;
}

.page-about .field-list .fnum {
  font-family: var(--font-mono);
  font-size: .76rem;
  color: var(--copper);
}

.page-about .field-list .ftext {
  font-size: .93rem;
  line-height: 1.75;
}

.page-about .field-list strong {
  color: var(--build);
}

.page-about .standard-note {
  font-size: .9rem !important;
  color: var(--steel) !important;
  padding-left: .85rem;
  border-left: 3px solid var(--amber);
}

/* 支持分档 */
.page-about .tier {
  margin-top: .75rem;
  padding: .95rem 1.05rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--ab-line);
  border-left: 4px solid var(--steel);
  background: #FFFFFF;
}

.page-about .tier--current {
  border-left-color: var(--build);
}

.page-about .tier--prev {
  border-left-color: var(--steel);
}

.page-about .tier--old {
  border-left-color: var(--wine);
}

.page-about .tier__tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .12em;
  color: var(--steel);
  margin: 0 0 .3rem;
}

.page-about .tier__title {
  font-size: 1.06rem;
  margin-bottom: .25rem;
  color: var(--ink-900);
}

.page-about .tier p {
  font-size: .92rem;
  color: var(--ink-700);
}

.page-about .support-note {
  margin-top: 1rem !important;
  font-size: .92rem !important;
  color: var(--steel) !important;
}

/* 服务规模 */
.page-about .scale-intro {
  font-size: .94rem !important;
  color: rgba(217, 226, 232, .78) !important;
  margin-bottom: 1.1rem;
}

.page-about .stat-grid {
  display: grid;
  gap: .7rem;
}

.page-about .stat {
  padding: .9rem 1rem;
  border-radius: var(--radius-sm);
  background: rgba(245, 241, 232, .06);
  border: 1px solid rgba(217, 226, 232, .15);
}

.page-about .stat__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1.4rem, 4.6vw, 1.95rem);
  letter-spacing: .02em;
  line-height: 1.2;
  color: var(--amber);
}

.page-about .stat__label {
  display: block;
  margin-top: .2rem;
  font-size: .86rem;
  color: rgba(245, 241, 232, .88);
}

.page-about .stat__note {
  display: block;
  margin-top: .28rem;
  font-size: .76rem;
  line-height: 1.6;
  color: rgba(217, 226, 232, .6);
}

.page-about .scale-foot {
  margin-top: 1.1rem !important;
  font-size: .9rem !important;
  color: rgba(217, 226, 232, .78) !important;
}

/* 后续计划 */
.page-about .next-list {
  display: grid;
  gap: .7rem;
}

.page-about .next-card {
  padding: .95rem 1.05rem;
  border-radius: var(--radius-sm);
  background: rgba(215, 166, 74, .12);
  border: 1px solid rgba(215, 166, 74, .38);
}

.page-about .next-card__title {
  font-size: 1.02rem;
  margin-bottom: .25rem;
  color: var(--amber);
}

.page-about .next-card p {
  font-size: .9rem;
  color: rgba(245, 241, 232, .84);
}

.page-about .next-note {
  margin-top: 1rem !important;
  font-size: .92rem !important;
  color: rgba(245, 241, 232, .82) !important;
}

.page-about .cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: .55rem;
  margin-top: 1.2rem;
}

.page-about .cta-row .btn {
  text-decoration: none;
  font-size: .9rem;
}

.page-about .cta-row .btn:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 3px;
}

/* 断点 */
@media (min-width: 560px) {
  .page-about .stat-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

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

@media (min-width: 780px) {
  .page-about .split {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, .95fr);
    align-items: start;
  }

  .page-about .split--rev > .split__media {
    order: 2;
  }

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

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.45fr) minmax(0, .75fr);
    align-items: end;
  }

  .page-about .stat-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

@media (min-width: 960px) {
  .page-about .about-body {
    grid-template-columns: 190px minmax(0, 1fr);
    align-items: start;
    gap: clamp(2rem, 4vw, 3.4rem);
  }

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

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

  .page-about .about-toc nav {
    display: block;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .toc-link {
    border: 0;
    border-radius: 0;
    border-left: 2px solid var(--ab-line);
    padding: .38rem 0 .38rem .8rem;
    font-size: .88rem;
    white-space: normal;
  }

  .page-about .toc-link.is-active {
    background: transparent;
    color: var(--ink-900);
    border-left-color: var(--amber);
    font-weight: 600;
  }

  .page-about .about-section {
    padding: clamp(1.6rem, 3vw, 2.5rem);
  }
}

@media (min-width: 1100px) {
  .page-about .about-rotate {
    display: block;
    position: absolute;
    right: 20px;
    top: 30%;
    z-index: 1;
    writing-mode: vertical-rl;
    margin: 0;
    max-width: none;
    font-family: var(--font-mono);
    font-size: .72rem;
    letter-spacing: .42em;
    color: rgba(215, 166, 74, .78);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .toc-link,
  .page-about .tl-details,
  .page-about .tl-mark::after,
  .page-about .about-crumb a {
    transition: none;
  }
}