.page-about {
  --about-stack: 28px;
  --about-hair: 1px;
  display: block;
  background:
    radial-gradient(1200px 520px at 82% -8%, rgba(59, 240, 198, 0.07), transparent 62%),
    linear-gradient(180deg, rgba(12, 31, 25, 0.5), transparent 320px);
}

/* ---------- 面包屑 ---------- */
.page-about .about-crumb {
  padding-top: 24px;
  padding-bottom: 12px;
}
.page-about .breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.06em;
  color: var(--dim);
}
.page-about .breadcrumb__list li + li::before {
  content: "/";
  margin-right: 8px;
  color: var(--muted);
}
.page-about .breadcrumb__list a {
  color: var(--dim);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}
.page-about .breadcrumb__list a:hover {
  color: var(--ink);
  border-bottom-color: var(--accent);
}
.page-about .breadcrumb__list [aria-current="page"] {
  color: var(--accent);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--gap);
  padding-bottom: 40px;
}
.page-about .about-hero__eyebrow {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent);
}
.page-about .about-hero h1 {
  margin: 0 0 18px;
  font-family: var(--font-display);
  font-size: 32px;
  line-height: 1.25;
  letter-spacing: 0.01em;
  font-weight: 800;
  color: var(--ink);
  max-width: 20ch;
}
.page-about .about-hero__lead {
  margin: 0 0 24px;
  max-width: 46ch;
  font-size: var(--fs-16);
  line-height: 1.75;
  color: var(--dim);
}
.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 28px;
}
.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1px;
  margin: 0;
  padding: 0;
  background: var(--line);
  border: var(--about-hair) solid var(--line);
  clip-path: polygon(var(--cut) 0, 100% 0, 100% calc(100% - var(--cut)), calc(100% - var(--cut)) 100%, 0 100%, 0 var(--cut));
}
.page-about .about-fact {
  margin: 0;
  padding: 14px 16px;
  background: var(--panel);
}
.page-about .about-fact dt {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.1em;
  color: var(--dim);
  margin-bottom: 6px;
}
.page-about .about-fact dd {
  margin: 0;
  font-size: var(--fs-16);
  color: var(--ink);
}
.page-about .about-hero__media {
  margin: 0;
}
.page-about .about-hero__media .media-frame {
  border: var(--about-hair) solid var(--line);
}
.page-about .media-frame__caption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.05em;
  color: var(--dim);
}

/* ---------- 主壳：窄栏 + 内容 ---------- */
.page-about .about-shell {
  padding-bottom: 64px;
}
.page-about .about-shell .shell__aside {
  align-self: start;
}
.page-about .about-rail {
  border: var(--about-hair) solid var(--line);
  background: var(--panel);
  padding: 16px 14px;
  clip-path: polygon(var(--cut) 0, 100% 0, 100% 100%, 0 100%, 0 var(--cut));
}
.page-about .about-rail__title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--dim);
}
.page-about .rail__list {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 4px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}
.page-about .rail__item {
  flex: 0 0 auto;
}
.page-about .rail__link {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 7px 12px;
  border: var(--about-hair) solid var(--line);
  background: var(--card);
  color: var(--dim);
  text-decoration: none;
  white-space: nowrap;
  font-size: var(--fs-14);
  clip-path: polygon(var(--cut-sm) 0, 100% 0, 100% 100%, 0 100%, 0 var(--cut-sm));
  transition: color 180ms ease, border-color 180ms ease, background 180ms ease;
}
.page-about .rail__num {
  font-size: var(--fs-12);
  color: var(--muted);
}
.page-about .rail__link:hover,
.page-about .rail__link:focus-visible {
  color: var(--ink);
  border-color: var(--muted);
}
.page-about .rail__item.is-current .rail__link {
  color: var(--accent);
  border-color: var(--accent);
  background: rgba(59, 240, 198, 0.12);
}
.page-about .rail__item.is-current .rail__num {
  color: var(--accent);
}

/* ---------- 章节面板 ---------- */
.page-about .about-phase {
  background: var(--panel);
  border: var(--about-hair) solid var(--line);
  padding: 22px 18px 26px;
  clip-path: polygon(var(--cut) 0, 100% 0, 100% calc(100% - var(--cut)), calc(100% - var(--cut)) 100%, 0 100%, 0 var(--cut));
  scroll-margin-top: 96px;
}
.page-about .about-phase + .about-phase,
.page-about .about-close {
  margin-top: var(--panel-gap);
}
.page-about .panel__head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding-bottom: 14px;
  margin-bottom: 18px;
  border-bottom: var(--about-hair) solid var(--line);
}
.page-about .panel__index {
  flex: 0 0 auto;
  font-size: var(--fs-12);
  letter-spacing: 0.1em;
  color: var(--data);
}
.page-about .panel__title {
  margin: 0;
  font-family: var(--font-display);
  font-size: var(--fs-20);
  line-height: 1.35;
  letter-spacing: 0.02em;
  font-weight: 800;
  color: var(--ink);
}
.page-about .about-phase__text {
  margin: 0 0 14px;
  max-width: 58ch;
  font-size: var(--fs-16);
  line-height: 1.75;
  color: var(--dim);
}
.page-about .about-phase__text:last-child {
  margin-bottom: 0;
}

/* ---------- 01 发展脉络 ---------- */
.page-about .about-timeline {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
}
.page-about .about-timeline__node {
  position: relative;
  padding: 12px 14px 12px 18px;
  background: var(--card);
  border-left: 3px solid var(--muted);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 10px), calc(100% - 10px) 100%, 0 100%);
  transition: border-color 180ms ease;
}
.page-about .about-timeline__node:hover {
  border-left-color: var(--accent);
}
.page-about .about-timeline__tag {
  display: inline-block;
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.12em;
  color: var(--accent);
}
.page-about .about-timeline__desc {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--dim);
}

/* ---------- 02 团队 ---------- */
.page-about .about-team {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--gap);
}
.page-about .about-team__media {
  margin: 0;
  order: -1;
}
.page-about .about-team__media .media-frame {
  border: var(--about-hair) solid var(--line);
}
.page-about .about-roles {
  display: grid;
  gap: 18px;
  margin-top: 22px;
  padding-top: 18px;
  border-top: var(--about-hair) dashed var(--line);
}
.page-about .about-roles__chart {
  position: relative;
  width: 168px;
  height: 168px;
  margin: 0 auto;
  border-radius: 50%;
  background: conic-gradient(
    var(--accent) 0turn 0.643turn,
    var(--data) 0.643turn 0.857turn,
    var(--muted) 0.857turn 1turn
  );
  display: grid;
  place-items: center;
}
.page-about .about-roles__ring {
  position: absolute;
  inset: 16px;
  border-radius: 50%;
  background: var(--panel);
}
.page-about .about-roles__center {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 4px;
  font-size: var(--fs-14);
  color: var(--dim);
}
.page-about .about-roles__center .num {
  font-size: var(--fs-28);
}
.page-about .about-roles__list {
  display: grid;
  gap: 10px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.page-about .about-roles__item {
  display: grid;
  grid-template-columns: auto 1fr auto;
  grid-template-areas:
    "dot name num"
    "duty duty duty";
  gap: 4px 10px;
  padding: 10px 12px;
  background: var(--card);
  clip-path: polygon(var(--cut-sm) 0, 100% 0, 100% 100%, 0 100%, 0 var(--cut-sm));
  transition: background 180ms ease;
}
.page-about .about-roles__item:hover {
  background: #164034;
}
.page-about .about-roles__dot {
  grid-area: dot;
  align-self: center;
  width: 8px;
  height: 8px;
  border-radius: 50%;
}
.page-about .about-roles__dot--a { background: var(--accent); }
.page-about .about-roles__dot--b { background: var(--data); }
.page-about .about-roles__dot--c { background: var(--muted); }
.page-about .about-roles__name {
  grid-area: name;
  font-size: var(--fs-14);
  color: var(--ink);
}
.page-about .about-roles__num {
  grid-area: num;
  font-size: var(--fs-20);
}
.page-about .about-roles__duty {
  grid-area: duty;
  font-size: var(--fs-12);
  line-height: 1.6;
  color: var(--dim);
}

/* ---------- 03 生产线 ---------- */
.page-about .about-flows {
  display: grid;
  gap: 12px;
  margin-top: 8px;
}
.page-about .about-flow {
  background: var(--card);
  border: var(--about-hair) solid var(--line);
  clip-path: polygon(var(--cut-sm) 0, 100% 0, 100% calc(100% - 12px), calc(100% - 12px) 100%, 0 100%, 0 var(--cut-sm));
}
.page-about .about-flow__head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  padding: 14px 16px;
  cursor: pointer;
  list-style: none;
  font-size: var(--fs-16);
  color: var(--ink);
}
.page-about .about-flow__head::-webkit-details-marker { display: none; }
.page-about .about-flow__tag {
  display: grid;
  place-items: center;
  width: 24px;
  height: 24px;
  font-size: var(--fs-12);
  color: var(--floor);
  background: var(--accent);
  clip-path: polygon(var(--cut-sm) 0, 100% 0, 100% 100%, 0 100%, 0 var(--cut-sm));
}
.page-about .about-flow__name {
  font-family: var(--font-display);
  font-weight: 800;
  letter-spacing: 0.04em;
}
.page-about .about-flow__hint {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.05em;
  color: var(--dim);
}
.page-about .about-flow[open] .about-flow__head {
  border-bottom: var(--about-hair) solid var(--line);
}
.page-about .about-flow__inner {
  padding: 16px;
}
.page-about .about-flow__steps {
  display: grid;
  gap: 14px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.page-about .about-flow__steps li {
  display: grid;
  grid-template-columns: auto 1fr;
  grid-template-areas:
    "num name"
    "num desc";
  gap: 2px 12px;
  padding-left: 12px;
  border-left: 2px solid var(--muted);
}
.page-about .about-flow__step-num {
  grid-area: num;
  font-size: var(--fs-12);
  color: var(--data);
  padding-top: 3px;
}
.page-about .about-flow__step-name {
  grid-area: name;
  font-size: var(--fs-14);
  color: var(--ink);
}
.page-about .about-flow__steps p {
  grid-area: desc;
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--dim);
}

/* ---------- 04 覆盖与合作 ---------- */
.page-about .about-reach {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--gap);
}
.page-about .about-projects {
  margin: 20px 0 0;
  padding-top: 18px;
  border-top: var(--about-hair) dashed var(--line);
}
.page-about .about-projects__label {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--dim);
}
.page-about .about-projects__list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.page-about .about-reach__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 22px;
}
.page-about .about-reach__map {
  padding: 18px;
  background: var(--card);
  border: var(--about-hair) solid var(--line);
  clip-path: polygon(var(--cut) 0, 100% 0, 100% calc(100% - var(--cut)), calc(100% - var(--cut)) 100%, 0 100%, 0 var(--cut));
}
.page-about .about-map__caption {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.1em;
  color: var(--dim);
}
.page-about .about-map__caption .num {
  font-size: var(--fs-20);
}
.page-about .about-map__dots {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 8px;
}
.page-about .about-map__dot {
  display: block;
  aspect-ratio: 1 / 1;
  border-radius: 50%;
  background: var(--muted);
  opacity: 0.3;
}
.page-about .about-map__dot--on {
  background: var(--accent);
  opacity: 0.85;
}

/* ---------- 05 案例合集 ---------- */
.page-about .about-cases {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--gap);
}
.page-about .about-cases__media {
  margin: 0;
}
.page-about .about-cases__media .media-frame {
  border: var(--about-hair) solid var(--line);
}
.page-about .about-cases__axis {
  display: grid;
  gap: 1px;
  margin: 20px 0 0;
  background: var(--line);
  border: var(--about-hair) solid var(--line);
}
.page-about .about-cases__axis-item {
  padding: 14px 16px;
  background: var(--card);
}
.page-about .about-cases__axis-item dt {
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.1em;
  color: var(--accent);
}
.page-about .about-cases__axis-item dd {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--dim);
}
.page-about .about-cases__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 22px;
}

/* ---------- 06 纠错与版本 ---------- */
.page-about .about-upkeep {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--gap);
}
.page-about .about-upkeep__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 20px;
}
.page-about .about-quote {
  margin: 0;
  padding: 20px 18px;
  background: linear-gradient(180deg, rgba(59, 240, 198, 0.08), rgba(59, 240, 198, 0.02));
  border-left: 3px solid var(--accent);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 14px), calc(100% - 14px) 100%, 0 100%);
}
.page-about .about-quote__label {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
}
.page-about .about-quote__text {
  margin: 0 0 14px;
  font-size: var(--fs-16);
  line-height: 1.75;
  color: var(--ink);
}
.page-about .about-quote__foot {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding-top: 12px;
  border-top: var(--about-hair) solid var(--line);
  font-size: var(--fs-12);
  color: var(--dim);
}

/* ---------- 收尾 ---------- */
.page-about .about-close {
  background: var(--card);
  border: var(--about-hair) solid var(--line);
  padding: 24px 18px;
  clip-path: polygon(var(--cut) 0, 100% 0, 100% calc(100% - var(--cut)), calc(100% - var(--cut)) 100%, 0 100%, 0 var(--cut));
}
.page-about .about-close__inner {
  display: grid;
  gap: 20px;
  grid-template-columns: 1fr;
}
.page-about .about-close__title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: var(--fs-20);
  line-height: 1.35;
  letter-spacing: 0.02em;
  font-weight: 800;
  color: var(--ink);
}
.page-about .about-close__text p {
  margin: 0;
  max-width: 52ch;
  font-size: var(--fs-16);
  line-height: 1.75;
  color: var(--dim);
}
.page-about .about-close__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-content: start;
}
.page-about .about-close__contact {
  margin: 20px 0 0;
  padding-top: 16px;
  border-top: var(--about-hair) dashed var(--line);
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--dim);
}
.page-about .about-close__contact a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid rgba(59, 240, 198, 0.45);
}
.page-about .about-close__contact a:hover {
  border-bottom-width: 2px;
}

/* ---------- 显现动画 ---------- */
.page-about [data-reveal] {
  opacity: 1;
}
.page-about .js-ready [data-reveal] {
  opacity: 0;
  transform: translateY(12px);
}
.page-about .js-ready [data-reveal].is-visible {
  opacity: 1;
  transform: none;
  transition: opacity 240ms ease-out, transform 240ms ease-out;
}

/* ---------- 平板 ---------- */
@media (min-width: 720px) {
  .page-about .about-hero {
    grid-template-columns: 5fr 7fr;
    align-items: start;
    gap: 32px;
    padding-bottom: 48px;
  }
  .page-about .about-hero h1 {
    font-size: var(--fs-40);
  }
  .page-about .about-hero__media {
    position: sticky;
    top: 88px;
  }
  .page-about .about-phase {
    padding: 26px 24px 30px;
  }
  .page-about .panel__title {
    font-size: var(--fs-28);
  }
  .page-about .about-timeline {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 12px;
  }
  .page-about .about-timeline__node {
    border-left: none;
    border-top: 3px solid var(--muted);
    padding: 14px 14px 16px;
    clip-path: polygon(var(--cut-sm) 0, 100% 0, 100% calc(100% - 12px), calc(100% - 12px) 100%, 0 100%, 0 var(--cut-sm));
  }
  .page-about .about-timeline__node:hover {
    border-top-color: var(--accent);
  }
  .page-about .about-roles {
    grid-template-columns: auto 1fr;
    align-items: center;
    gap: 24px;
  }
  .page-about .about-roles__chart {
    margin: 0;
  }
  .page-about .about-flow__steps {
    grid-template-columns: repeat(3, 1fr);
  }
  .page-about .about-flow__steps li {
    grid-template-columns: 1fr;
    grid-template-areas:
      "num"
      "name"
      "desc";
    border-left: none;
    border-top: 2px solid var(--muted);
    padding: 12px 0 0;
  }
  .page-about .about-close__inner {
    grid-template-columns: 7fr 5fr;
    align-items: center;
  }
  .page-about .about-close__actions {
    justify-content: flex-end;
  }
}

/* ---------- 桌面 ---------- */
@media (min-width: 960px) {
  .page-about .about-hero h1 {
    font-size: var(--fs-56);
    max-width: 16ch;
  }
  .page-about .about-shell {
    display: grid;
    grid-template-columns: 180px minmax(0, 1fr);
    gap: 32px;
    align-items: start;
  }
  .page-about .about-rail {
    position: sticky;
    top: 88px;
    padding: 18px 14px;
  }
  .page-about .rail__list {
    flex-direction: column;
    gap: 4px;
    overflow: visible;
    padding-bottom: 0;
  }
  .page-about .rail__link {
    width: 100%;
    border-color: transparent;
    background: transparent;
    clip-path: none;
    border-left: 2px solid var(--muted);
    padding: 9px 10px;
  }
  .page-about .rail__link:hover,
  .page-about .rail__link:focus-visible {
    border-left-color: var(--dim);
    background: rgba(30, 74, 60, 0.4);
  }
  .page-about .rail__item.is-current .rail__link {
    border-left-color: var(--accent);
    background: rgba(59, 240, 198, 0.1);
  }
  .page-about .about-phase {
    padding: 30px 32px 36px;
  }
  .page-about .about-team {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 32px;
    align-items: start;
  }
  .page-about .about-team__media {
    order: 0;
  }
  .page-about .about-reach {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 32px;
    align-items: start;
  }
  .page-about .about-cases {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    gap: 32px;
    align-items: start;
  }
  .page-about .about-upkeep {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 32px;
    align-items: start;
  }
  .page-about .about-close {
    padding: 32px;
  }
  .page-about .about-close__title {
    font-size: var(--fs-28);
  }
  .page-about .about-map__dots {
    grid-template-columns: repeat(6, 1fr);
    gap: 10px;
  }
}

@media (min-width: 1200px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(3, 1fr);
  }
  .page-about .about-phase__text {
    font-size: var(--fs-16);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .js-ready [data-reveal] {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .page-about .rail__link,
  .page-about .about-timeline__node,
  .page-about .about-roles__item {
    transition: none;
  }
}