.page-about {
  --about-text: rgba(244, 247, 250, 0.84);
  --about-strong: var(--warm);
  --about-muted: var(--lake-soft);
  --about-line: var(--line-dark);
  --about-accent: var(--gold);
  --about-panel: rgba(23, 42, 94, 0.52);

  background: var(--night);
  color: var(--about-text);
  overflow-x: clip;
}

/* ---------- 面包屑 ---------- */
.page-about .about-crumb {
  padding-block: clamp(18px, 3vw, 32px) 0;
}

.page-about .breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
  font-size: 13px;
  letter-spacing: 0.06em;
}

.page-about .breadcrumb-item {
  display: inline-flex;
  align-items: center;
  color: var(--slate);
}

.page-about .breadcrumb-item + .breadcrumb-item::before {
  content: "/";
  margin: 0 10px;
  color: var(--lake);
  opacity: 0.8;
}

.page-about .breadcrumb-link {
  color: var(--lake-soft);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.25s ease, border-color 0.25s ease;
}

.page-about .breadcrumb-link:hover,
.page-about .breadcrumb-link:focus-visible {
  color: var(--gold);
  border-bottom-color: var(--gold);
}

.page-about .breadcrumb-current {
  color: var(--gold-soft);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding-block: clamp(30px, 5vw, 62px) clamp(52px, 8vw, 108px);
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(28px, 5vw, 56px);
}

.page-about .about-hero__mark {
  margin: 0 0 clamp(16px, 2.4vw, 26px);
  font-size: 12.5px;
  letter-spacing: 0.2em;
  color: var(--lake-soft);
  text-transform: uppercase;
}

.page-about .about-hero__title {
  margin: 0 0 clamp(18px, 2.6vw, 26px);
  font-size: clamp(32px, 6.2vw, 66px);
  line-height: 1.1;
  letter-spacing: -0.012em;
  color: var(--warm);
}

.page-about .about-hero__lead {
  max-width: 44ch;
  margin: 0;
  font-size: clamp(16px, 1.5vw, 18px);
  line-height: 1.85;
  color: var(--lake-soft);
}

.page-about .about-hero__stats {
  display: flex;
  flex-wrap: wrap;
  gap: clamp(22px, 4vw, 52px);
  margin: clamp(28px, 4vw, 42px) 0 0;
  padding-top: clamp(20px, 3vw, 28px);
  border-top: 1px solid var(--line-dark);
}

.page-about .about-stat dt {
  margin: 0 0 8px;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--slate);
}

.page-about .about-stat dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(26px, 3.4vw, 36px);
  font-weight: 700;
  line-height: 1;
  color: var(--gold);
}

.page-about .about-stat dd span {
  margin-left: 4px;
  font-size: 13px;
  font-weight: 500;
  color: var(--gold-soft);
  letter-spacing: 0.02em;
}

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

.page-about .about-hero__figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 14 / 9;
  object-fit: cover;
  border: 2px solid var(--line-dark);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 28px), calc(100% - 28px) 100%, 0 100%);
}

/* ---------- 章节通用 ---------- */
.page-about .about-sec {
  position: relative;
  padding-block: clamp(52px, 8vw, 112px);
  color: var(--about-text);
}

.page-about .about-sec--paper {
  --about-text: #33405a;
  --about-strong: var(--ink);
  --about-muted: var(--slate);
  --about-line: var(--line-light);
  --about-accent: var(--lake);
  --about-panel: var(--warm);

  background: var(--paper);
  color: var(--ink);
}

.page-about .about-sec__grid {
  display: grid;
  gap: clamp(18px, 3vw, 32px);
}

.page-about .about-sec__marker {
  display: flex;
  align-items: flex-start;
  gap: 14px;
}

.page-about .about-sec__marker--row {
  margin-bottom: clamp(10px, 2vw, 18px);
}

.page-about .about-sec__index {
  display: block;
  font-size: clamp(58px, 10vw, 126px);
  font-weight: 700;
  line-height: 0.84;
  letter-spacing: -0.02em;
  color: transparent;
  -webkit-text-stroke: 2px var(--lake-soft);
  opacity: 0.46;
  transition: opacity 0.45s ease, -webkit-text-stroke-color 0.45s ease;
}

.page-about .about-sec__index.is-visible,
.page-about .about-sec__index.is-active {
  opacity: 1;
  -webkit-text-stroke-color: var(--gold);
}

.page-about .about-sec--paper .about-sec__index {
  -webkit-text-stroke-color: var(--lake);
  opacity: 0.34;
}

.page-about .about-sec--paper .about-sec__index.is-visible,
.page-about .about-sec--paper .about-sec__index.is-active {
  opacity: 0.95;
  -webkit-text-stroke-color: var(--wine);
}

@supports not (-webkit-text-stroke: 1px #000) {
  .page-about .about-sec__index {
    color: var(--lake);
    opacity: 0.32;
  }
  .page-about .about-sec__index.is-visible,
  .page-about .about-sec__index.is-active {
    opacity: 0.9;
    color: var(--gold);
  }
}

.page-about .about-sec__side {
  margin-top: 8px;
  color: var(--about-muted);
  opacity: 0.85;
}

.page-about .about-sec__title {
  margin: 0 0 clamp(14px, 2vw, 22px);
  font-size: clamp(24px, 3.6vw, 40px);
  line-height: 1.26;
  letter-spacing: -0.008em;
  color: var(--about-strong);
}

.page-about .about-sec__lead {
  max-width: 34em;
  margin: 0 0 clamp(20px, 3vw, 30px);
  font-size: clamp(16px, 1.4vw, 18px);
  line-height: 1.88;
  color: var(--about-muted);
}

.page-about .about-sec__body p {
  max-width: 40em;
  margin: 0 0 clamp(16px, 2vw, 22px);
  font-size: clamp(15.5px, 1.32vw, 17.5px);
  line-height: 1.92;
  color: var(--about-text);
}

.page-about .about-sec__note {
  max-width: 40em;
  margin: clamp(20px, 3vw, 28px) 0 0;
  padding-top: 16px;
  border-top: 1px solid var(--about-line);
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--about-muted);
}

.page-about .text-link {
  color: var(--about-accent);
  text-decoration: none;
  border-bottom: 1px solid currentColor;
  padding-bottom: 1px;
  transition: color 0.25s ease;
}

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

/* ---------- 历程 ---------- */
.page-about .about-sec__intro {
  margin-bottom: clamp(24px, 4vw, 40px);
}

.page-about .about-track-figure {
  margin: 0 0 clamp(30px, 5vw, 52px);
}

.page-about .about-track-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 3 / 1;
  object-fit: cover;
  border: 2px solid var(--line-dark);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 22px), calc(100% - 22px) 100%, 0 100%);
}

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

.page-about .about-node {
  position: relative;
  z-index: 1;
  padding: 16px 16px 6px;
  background: var(--about-panel);
  border: 1px solid var(--about-line);
  border-left: 3px solid var(--lake);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 16px), calc(100% - 16px) 100%, 0 100%);
  transition: border-left-color 0.3s ease, background-color 0.3s ease;
}

.page-about .about-node[open] {
  border-left-color: var(--gold);
}

.page-about .about-node__head {
  display: flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .about-node__head::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 17px;
  line-height: 1;
  color: var(--about-accent);
  transition: transform 0.3s ease;
}

.page-about .about-node[open] .about-node__head::after {
  transform: rotate(45deg);
}

.page-about .about-node__num {
  flex: none;
  display: grid;
  place-items: center;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: var(--gold);
  color: var(--night);
  font-size: 12px;
  font-weight: 700;
}

.page-about .about-node__title {
  font-size: 15.5px;
  font-weight: 600;
  line-height: 1.45;
  color: var(--about-strong);
}

.page-about .about-node__body {
  margin: 12px 0 14px;
  padding-top: 12px;
  border-top: 1px solid var(--about-line);
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--about-text);
}

/* ---------- 复核步骤 ---------- */
.page-about .about-steps {
  display: grid;
  gap: 12px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-step {
  padding: 20px 18px 20px;
  background: var(--warm);
  border: 1px solid var(--about-line);
  border-left: 3px solid var(--lake);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 16px), calc(100% - 16px) 100%, 0 100%);
  transition: border-left-color 0.3s ease, transform 0.3s ease, box-shadow 0.3s ease;
}

.page-about .about-step:hover,
.page-about .about-step:focus-within {
  border-left-color: var(--gold);
  transform: translateY(-3px);
  box-shadow: 0 16px 32px rgba(16, 24, 40, 0.1);
}

.page-about .about-step__num {
  display: block;
  margin-bottom: 10px;
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--lake);
}

.page-about .about-step__title {
  margin: 0 0 8px;
  font-size: 17px;
  line-height: 1.4;
  color: var(--ink);
}

.page-about .about-step p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--slate);
}

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

.page-about .about-sec__figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  background: var(--night);
  border: 2px solid var(--about-line);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 24px), calc(100% - 24px) 100%, 0 100%);
}

.page-about .about-sec__figcap {
  margin-top: 14px;
  font-size: 13px;
  line-height: 1.75;
  color: var(--about-muted);
}

/* ---------- 团队 ---------- */
.page-about .about-team {
  display: grid;
  gap: clamp(28px, 5vw, 56px);
  align-items: center;
  margin-top: clamp(24px, 4vw, 40px);
}

.page-about .about-team__visual {
  text-align: center;
}

.page-about .about-team__ring {
  position: relative;
  width: min(258px, 66vw);
  aspect-ratio: 1;
  margin: 0 auto;
  border-radius: 50%;
  background: conic-gradient(
    var(--lake) 0turn 0.474turn,
    var(--gold) 0.474turn 0.79turn,
    var(--moss) 0.79turn 1turn
  );
  box-shadow: 0 0 0 1px var(--line-dark);
}

.page-about .about-team__ring::after {
  content: "";
  position: absolute;
  inset: 24%;
  border-radius: 50%;
  background: var(--night);
}

.page-about .about-team__cap {
  margin: 18px 0 0;
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--gold-soft);
}

.page-about .about-team__list {
  display: grid;
  gap: 14px;
  margin: 0 0 clamp(18px, 3vw, 26px);
  padding: 0;
  list-style: none;
}

.page-about .about-team__row {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line-dark-soft);
}

.page-about .about-team__dot {
  flex: none;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  transform: translateY(-1px);
}

.page-about .about-team__dot--lake {
  background: var(--lake);
}

.page-about .about-team__dot--gold {
  background: var(--gold);
}

.page-about .about-team__dot--moss {
  background: var(--moss);
}

.page-about .about-team__role {
  font-size: 16px;
  color: var(--warm);
}

.page-about .about-team__count {
  margin-left: auto;
  font-size: 22px;
  font-weight: 700;
  color: var(--gold);
}

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

.page-about .about-team__text {
  max-width: 40em;
  margin: 0 0 16px;
  font-size: clamp(15px, 1.3vw, 17px);
  line-height: 1.9;
  color: var(--about-text);
}

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

/* ---------- 备案标签 ---------- */
.page-about .about-doc {
  display: grid;
  gap: 14px;
  margin: clamp(20px, 3vw, 28px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-doc__tag {
  padding: 20px 20px 24px;
  background: var(--indigo);
  border-left: 3px solid var(--lake);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 18px), calc(100% - 18px) 100%, 0 100%);
}

.page-about .about-doc__k {
  display: block;
  margin-bottom: 8px;
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--lake-soft);
}

.page-about .about-doc__v {
  display: block;
  font-size: clamp(15px, 1.6vw, 18px);
  line-height: 1.6;
  color: var(--warm);
}

/* ---------- 反馈收束 ---------- */
.page-about .about-feedback {
  display: grid;
  gap: 14px;
  margin: 0 0 clamp(26px, 4vw, 38px);
  padding: 0;
  list-style: none;
}

.page-about .about-feedback li {
  display: grid;
  gap: 6px;
  max-width: 40em;
  padding-left: 16px;
  border-left: 2px solid var(--lake);
  font-size: clamp(15px, 1.3vw, 17px);
  line-height: 1.85;
  color: var(--about-text);
}

.page-about .about-feedback__k {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.12em;
  color: var(--gold);
}

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

/* ---------- 响应式 ---------- */
@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: end;
    gap: clamp(36px, 5vw, 76px);
  }

  .page-about .about-sec__grid {
    grid-template-columns: 130px minmax(0, 1fr);
    gap: clamp(24px, 4vw, 68px);
  }

  .page-about .about-sec__grid--split {
    grid-template-columns: 130px minmax(0, 1.08fr) minmax(0, 0.92fr);
    align-items: start;
  }

  .page-about .about-sec__marker {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }

  .page-about .about-sec__marker--row {
    flex-direction: row;
    align-items: flex-end;
    gap: clamp(16px, 3vw, 32px);
  }

  .page-about .about-sec__side {
    margin-top: 0;
  }

  .page-about .about-steps {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 14px;
  }

  .page-about .about-team {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  }

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

  .page-about .about-track {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 16px;
    align-items: start;
    padding-top: 26px;
  }

  .page-about .about-track::before {
    content: "";
    position: absolute;
    left: 1%;
    right: 3%;
    top: 46px;
    height: 2px;
    background: linear-gradient(90deg, var(--lake), var(--gold));
    transform: rotate(-3.4deg);
    transform-origin: left center;
    opacity: 0.5;
    pointer-events: none;
    z-index: 0;
  }

  .page-about .about-track__item:nth-child(2) {
    margin-top: 14px;
  }

  .page-about .about-track__item:nth-child(3) {
    margin-top: 28px;
  }

  .page-about .about-track__item:nth-child(4) {
    margin-top: 42px;
  }

  .page-about .about-track__item:nth-child(5) {
    margin-top: 56px;
  }
}

@media (max-width: 899px) {
  .page-about .about-sec__side {
    display: none;
  }

  .page-about .about-sec__index {
    -webkit-text-stroke-width: 1.5px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-step,
  .page-about .about-node,
  .page-about .about-node__head::after,
  .page-about .about-sec__index,
  .page-about .breadcrumb-link {
    transition: none;
  }

  .page-about .about-step:hover,
  .page-about .about-step:focus-within {
    transform: none;
  }
}