.page-about {
  background: var(--paper);
  color: var(--ink-900);
  font-family: var(--font-sans);
  overflow-x: hidden;
}

/* ---------- Hero ---------- */
.page-about .ab-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  background:
    radial-gradient(90% 60% at 92% -10%, rgba(245, 154, 27, .22), rgba(245, 154, 27, 0) 62%),
    radial-gradient(70% 55% at 4% 108%, rgba(79, 191, 160, .16), rgba(79, 191, 160, 0) 70%),
    var(--ink-900);
  color: var(--paper);
  padding: 20px 0 0;
}

.page-about .ab-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(201, 210, 220, .055) 1px, transparent 1px),
    linear-gradient(90deg, rgba(201, 210, 220, .055) 1px, transparent 1px);
  background-size: 72px 72px;
  -webkit-mask-image: linear-gradient(180deg, #000, transparent 78%);
  mask-image: linear-gradient(180deg, #000, transparent 78%);
}

.page-about .ab-hero__crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--stone-400);
}

.page-about .ab-hero__crumbs .crumbs__link {
  color: var(--stone-200);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}

.page-about .ab-hero__crumbs .crumbs__link:hover {
  color: var(--amber-300);
  border-color: currentColor;
}

.page-about .ab-hero__crumbs .crumbs__current {
  color: var(--paper);
}

.page-about .ab-hero__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
  padding: 24px 0 34px;
}

.page-about .ab-hero__aside {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--amber-300);
}

.page-about .ab-hero__aside .idx {
  color: var(--amber-300);
}

.page-about .ab-hero__aside-label {
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--stone-400);
}

.page-about .ab-hero__title {
  margin: 0 0 20px;
  font-size: clamp(34px, 8.4vw, 74px);
  line-height: 1.04;
  letter-spacing: -.02em;
  font-weight: 800;
  color: var(--white);
}

.page-about .ab-hero__lede {
  margin: 0 0 26px;
  max-width: 46ch;
  font-size: 16px;
  line-height: 1.85;
  color: var(--stone-200);
}

.page-about .ab-hero__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-hero__meta li {
  padding: 7px 13px;
  border: 1px solid var(--line-dark);
  border-radius: 999px;
  background: rgba(20, 38, 58, .6);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--stone-200);
}

.page-about .ab-hero__media {
  position: relative;
}

.page-about .ab-hero__media .media {
  margin: 0;
  border-radius: var(--radius) var(--radius) 0 0;
  overflow: hidden;
  background: var(--ink-800);
  box-shadow: 0 -18px 44px rgba(14, 27, 42, .35);
}

/* ---------- Shared page media ---------- */
.page-about .media {
  margin: 0;
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--ink-800);
}

.page-about .media__img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  max-width: 100%;
}

.page-about .ab-hero__media .media__img {
  aspect-ratio: 16 / 9;
}

.page-about .media__caption {
  padding: 10px 14px 12px;
  font-size: 12px;
  line-height: 1.7;
  letter-spacing: .04em;
  color: var(--stone-400);
  background: var(--ink-800);
}

/* ---------- Sections ---------- */
.page-about .ab-sec {
  position: relative;
  padding: 56px 0;
}

.page-about .ab-sec--lead {
  padding-top: 64px;
}

.page-about .ab-sec--tight {
  padding-top: 44px;
}

.page-about .ab-sec--dark {
  background: var(--ink-900);
  color: var(--paper);
}

.page-about .ab-head {
  max-width: 720px;
  margin-bottom: 30px;
}

.page-about .ab-head h2 {
  margin: 12px 0 14px;
  font-size: clamp(24px, 4.6vw, 40px);
  line-height: 1.2;
  letter-spacing: -.015em;
  font-weight: 800;
}

.page-about .ab-head p {
  margin: 0;
  font-size: 16px;
  line-height: 1.85;
  color: var(--ink-700);
}

.page-about .ab-sec--dark .ab-head p {
  color: var(--stone-200);
}

/* ---------- Two moments ---------- */
.page-about .ab-moments {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

.page-about .ab-moment {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  padding: 24px 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--white);
  transition: transform var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}

.page-about .ab-moment:hover {
  transform: translateY(-2px);
  border-color: var(--amber-500);
}

.page-about .ab-moment--dark {
  background: linear-gradient(160deg, var(--ink-800), var(--ink-900));
  border-color: var(--line-dark);
  color: var(--paper);
}

.page-about .ab-moment--dark:hover {
  border-color: var(--amber-500);
}

.page-about .ab-moment__title {
  margin: 16px 0 12px;
  font-size: 20px;
  line-height: 1.4;
  letter-spacing: -.01em;
  font-weight: 700;
}

.page-about .ab-moment--dark .ab-moment__title {
  color: var(--white);
}

.page-about .ab-moment__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink-700);
}

.page-about .ab-moment--dark .ab-moment__text {
  color: var(--stone-200);
}

.page-about .ab-moment__link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-top: 18px;
  padding-bottom: 2px;
  font-size: 14px;
  color: var(--celadon-700);
  text-decoration: none;
  border-bottom: 1px solid currentColor;
  transition: color var(--t-fast) var(--ease);
}

.page-about .ab-moment__link:hover {
  color: var(--amber-500);
}

.page-about .ab-moment--dark .ab-moment__link {
  color: var(--amber-300);
}

.page-about .ab-moment--dark .ab-moment__link:hover {
  color: var(--white);
}

/* ---------- Timeline ---------- */
.page-about .ab-timeline {
  display: grid;
  grid-template-columns: 1fr;
  gap: 30px;
  margin-top: 32px;
}

.page-about .ab-timeline__list {
  position: relative;
  margin: 0;
  padding: 4px 0 4px 44px;
  list-style: none;
}

.page-about .ab-timeline__list::before {
  content: "";
  position: absolute;
  top: 8px;
  bottom: 8px;
  left: 7px;
  width: 2px;
  background: linear-gradient(180deg, rgba(200, 112, 74, .85), rgba(79, 191, 160, .85));
}

.page-about .ab-timeline__item {
  position: relative;
  padding-bottom: 12px;
}

.page-about .ab-timeline__item::before {
  content: "";
  position: absolute;
  left: -44px;
  top: 18px;
  width: 16px;
  height: 16px;
  box-sizing: border-box;
  border: 2px solid var(--clay-500);
  border-radius: 50%;
  background: var(--paper);
}

.page-about .ab-timeline__item:nth-child(even)::before {
  border-color: var(--celadon-500);
}

.page-about .ab-node {
  border-radius: var(--radius-sm);
}

.page-about .ab-node__summary {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 14px;
  padding: 12px 14px;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  cursor: pointer;
  list-style: none;
  transition: background var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}

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

.page-about .ab-node__summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 15px;
  color: var(--stone-400);
  line-height: 1;
}

.page-about .ab-node[open] > .ab-node__summary::after {
  content: "−";
  color: var(--celadon-700);
}

.page-about .ab-node__summary:hover {
  background: var(--white);
  border-color: var(--stone-200);
}

.page-about .ab-node[open] > .ab-node__summary {
  background: var(--white);
  border-color: var(--line);
}

.page-about .ab-node__year {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .06em;
  color: var(--clay-500);
}

.page-about .ab-node__title {
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -.01em;
  color: var(--ink-900);
}

.page-about .ab-node__body {
  padding: 4px 14px 10px;
}

.page-about .ab-node__body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink-700);
}

.page-about .ab-timeline__aside .media__img {
  aspect-ratio: 5 / 7;
}

/* ---------- Team ---------- */
.page-about .ab-team {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

.page-about .ab-team__card {
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: 24px 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--white);
  transition: transform var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}

.page-about .ab-team__card:hover {
  transform: translateY(-2px);
  border-color: var(--amber-500);
}

.page-about .ab-team__num {
  font-size: 13px;
  letter-spacing: .16em;
  color: var(--stone-400);
}

.page-about .ab-team__name {
  margin: 0;
  font-size: 19px;
  letter-spacing: -.01em;
  font-weight: 700;
  color: var(--ink-900);
}

.page-about .ab-team__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink-700);
}

/* ---------- Standards ---------- */
.page-about .ab-standards {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  margin-top: 30px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--line);
  overflow: hidden;
}

.page-about .ab-stat {
  padding: 24px 20px;
  background: var(--paper);
  transition: background var(--t-fast) var(--ease);
}

.page-about .ab-stat:hover {
  background: var(--white);
}

.page-about .ab-stat__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(30px, 5vw, 46px);
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--ink-900);
}

.page-about .ab-stat__unit {
  margin-left: 6px;
  font-size: 13px;
  letter-spacing: .04em;
  color: var(--stone-400);
}

.page-about .ab-stat__label {
  display: block;
  margin: 14px 0 8px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: .16em;
  color: var(--celadon-700);
}

.page-about .ab-stat p {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--ink-700);
}

/* ---------- Certs ---------- */
.page-about .ab-cert-wrap {
  display: grid;
  grid-template-columns: 1fr;
  gap: 28px;
  align-items: start;
}

.page-about .ab-certs {
  display: grid;
  gap: 14px;
  padding: 8px 6px;
}

.page-about .ab-cert {
  padding: 20px 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--white);
  box-shadow: 0 10px 24px rgba(14, 27, 42, .06);
  transform: rotate(-1.1deg);
  transition: transform var(--t-fast) var(--ease), box-shadow var(--t-fast) var(--ease);
}

.page-about .ab-cert:nth-child(2) {
  transform: rotate(.9deg);
}

.page-about .ab-cert:nth-child(3) {
  transform: rotate(-.6deg);
}

.page-about .ab-cert:hover {
  transform: rotate(0deg) translateY(-3px);
  box-shadow: 0 16px 32px rgba(14, 27, 42, .1);
}

.page-about .ab-cert__name {
  margin: 14px 0 6px;
  font-size: 18px;
  line-height: 1.45;
  letter-spacing: -.01em;
  font-weight: 700;
  color: var(--ink-900);
}

.page-about .ab-cert__meta {
  margin: 0 0 10px;
  font-size: 13px;
  letter-spacing: .06em;
  color: var(--celadon-700);
}

.page-about .ab-cert__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink-700);
}

.page-about .ab-cert__media .media__img {
  aspect-ratio: 3 / 2;
}

/* ---------- Contact ---------- */
.page-about .ab-contact {
  padding: 28px 22px;
  border-radius: var(--radius);
  background:
    radial-gradient(80% 70% at 100% 0%, rgba(245, 154, 27, .18), rgba(245, 154, 27, 0) 65%),
    linear-gradient(150deg, var(--ink-800), var(--ink-900));
  border: 1px solid var(--line-dark);
}

.page-about .ab-contact__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 26px;
}

.page-about .ab-contact__title {
  margin: 12px 0 14px;
  font-size: clamp(22px, 4vw, 32px);
  line-height: 1.3;
  letter-spacing: -.015em;
  font-weight: 800;
  color: var(--white);
}

.page-about .ab-contact__lede {
  margin: 0;
  max-width: 44ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--stone-200);
}

.page-about .ab-next {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 22px;
}

.page-about .ab-next__link {
  display: inline-flex;
  align-items: center;
  padding: 10px 16px;
  border: 1px solid var(--line-dark);
  border-radius: 999px;
  font-size: 14px;
  color: var(--stone-200);
  text-decoration: none;
  transition: color var(--t-fast) var(--ease), background var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}

.page-about .ab-next__link:hover {
  color: var(--ink-900);
  background: var(--amber-500);
  border-color: var(--amber-500);
}

.page-about .ab-contact__list {
  display: flex;
  flex-direction: column;
}

.page-about .ab-contact__row {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line-dark);
}

.page-about .ab-contact__key {
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--stone-400);
}

.page-about .ab-contact__val {
  font-family: var(--font-mono);
  font-size: 15px;
  line-height: 1.7;
  color: var(--paper);
}

.page-about .ab-copy {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  align-self: flex-start;
  max-width: 100%;
  padding: 9px 14px;
  border: 1px solid rgba(245, 154, 27, .45);
  border-radius: 999px;
  background: rgba(245, 154, 27, .12);
  font-family: var(--font-mono);
  font-size: 14px;
  line-height: 1.5;
  color: var(--amber-300);
  text-align: left;
  word-break: break-all;
  cursor: pointer;
  transition: background var(--t-fast) var(--ease), color var(--t-fast) var(--ease);
}

.page-about .ab-copy:hover {
  background: rgba(245, 154, 27, .24);
  color: var(--white);
}

.page-about .ab-copy::after {
  content: "复制";
  flex: none;
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--stone-400);
}

.page-about .ab-copy[data-copied="true"]::after {
  content: "已复制";
  color: var(--celadon-500);
}

.page-about .ab-legal {
  margin: 18px 0 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--stone-400);
}

/* ---------- Media queries ---------- */
@media (min-width: 640px) {
  .page-about .ab-standards {
    grid-template-columns: 1fr 1fr;
  }

  .page-about .ab-contact__row {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    gap: 18px;
  }

  .page-about .ab-contact__key {
    flex: none;
  }

  .page-about .ab-contact__val,
  .page-about .ab-copy {
    text-align: right;
  }

  .page-about .ab-copy {
    align-self: auto;
  }
}

@media (min-width: 860px) {
  .page-about .ab-hero__grid {
    grid-template-columns: minmax(140px, 1fr) minmax(0, 2.6fr);
    gap: 40px;
    align-items: start;
    padding: 54px 0 60px;
  }

  .page-about .ab-hero__aside {
    align-items: flex-start;
    flex-direction: column;
    gap: 10px;
    padding-top: 10px;
  }

  .page-about .ab-moments {
    grid-template-columns: 1.05fr .95fr;
    gap: 22px;
    align-items: start;
  }

  .page-about .ab-moments .ab-moment:nth-child(2) {
    margin-top: 44px;
  }

  .page-about .ab-team {
    grid-template-columns: 1.15fr 1fr 1fr;
    gap: 18px;
  }

  .page-about .ab-timeline {
    grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
    gap: 48px;
    align-items: start;
  }

  .page-about .ab-timeline__list {
    padding-left: 96px;
  }

  .page-about .ab-timeline__item::before {
    left: -96px;
  }

  .page-about .ab-timeline__item:nth-child(odd) .ab-node {
    max-width: 96%;
  }

  .page-about .ab-timeline__item:nth-child(even) .ab-node {
    margin-left: 36px;
  }

  .page-about .ab-timeline__aside {
    position: sticky;
    top: calc(var(--topbar-h) + 24px);
  }

  .page-about .ab-cert-wrap {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, .9fr);
    gap: 44px;
  }

  .page-about .ab-contact {
    padding: 44px;
  }

  .page-about .ab-contact__grid {
    grid-template-columns: 1.05fr 1fr;
    gap: 44px;
  }
}

@media (min-width: 1024px) {
  .page-about .ab-sec {
    padding: 84px 0;
  }

  .page-about .ab-sec--lead {
    padding-top: 88px;
  }

  .page-about .ab-sec--tight {
    padding-top: 64px;
  }

  .page-about .ab-standards {
    grid-template-columns: repeat(4, 1fr);
  }

  .page-about .ab-head h2 {
    max-width: 20ch;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-moment,
  .page-about .ab-team__card,
  .page-about .ab-cert,
  .page-about .ab-node__summary,
  .page-about .ab-next__link,
  .page-about .ab-copy,
  .page-about .ab-stat {
    transition-duration: 120ms;
  }

  .page-about .ab-moment:hover,
  .page-about .ab-team__card:hover,
  .page-about .ab-cert:hover {
    transform: none;
  }
}