.page-about {
  --about-rail: 96px;
  padding-bottom: clamp(2.4rem, 6vw, 4.5rem);
}

/* ---------- 面包屑 ---------- */
.page-about .about-crumbs {
  padding-top: clamp(1.1rem, 3vw, 1.8rem);
  padding-bottom: clamp(.8rem, 2vw, 1.2rem);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding-block: clamp(1rem, 3vw, 1.8rem) clamp(2.2rem, 6vw, 4.2rem);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    linear-gradient(to right, var(--line-soft) 1px, transparent 1px),
    linear-gradient(to bottom, var(--line-soft) 1px, transparent 1px);
  background-size: 68px 68px;
  -webkit-mask-image: radial-gradient(130% 95% at 12% 0%, #000 0%, transparent 74%);
  mask-image: radial-gradient(130% 95% at 12% 0%, #000 0%, transparent 74%);
}

.page-about .about-hero-inner {
  position: relative;
  z-index: 1;
}

.page-about .about-h1 {
  margin: .7rem 0 1rem;
  max-width: 17ch;
  font-family: var(--font-sans);
  font-weight: 900;
  font-size: clamp(2.05rem, 6.2vw, 4.3rem);
  line-height: 1.05;
  letter-spacing: -0.028em;
  color: var(--paper);
}

.page-about .about-hero-lead {
  max-width: 60ch;
  margin: 0;
  font-family: var(--font-serif);
  font-size: clamp(1rem, 2vw, 1.18rem);
  line-height: 1.95;
  color: var(--mist);
}

.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(1.7rem, 4vw, 2.6rem) 0 0;
  padding: 0;
  list-style: none;
  border: 1px solid var(--line);
  border-radius: var(--r-m);
  background: var(--line);
  overflow: hidden;
}

.page-about .about-stats li {
  display: flex;
  flex-direction: column;
  gap: .3rem;
  padding: 1rem 1.1rem;
  background: var(--hull-deep);
}

.page-about .about-stats .stat-num {
  font-family: var(--font-mono);
  font-weight: 500;
  font-size: clamp(1.45rem, 3.6vw, 2rem);
  letter-spacing: .02em;
  color: var(--amber);
}

.page-about .about-stats .stat-label {
  font-size: .8rem;
  letter-spacing: .05em;
  color: var(--mist);
}

/* ---------- 通用区块 ---------- */
.page-about .about-section {
  padding-block: clamp(2.3rem, 6.5vw, 4.4rem);
  border-top: 1px solid var(--line-soft);
}

.page-about .section-title {
  margin: .55rem 0 .7rem;
  font-family: var(--font-sans);
  font-weight: 850;
  font-size: clamp(1.45rem, 3.6vw, 2.25rem);
  line-height: 1.22;
  letter-spacing: -0.018em;
  color: var(--paper);
}

.page-about .section-lead {
  max-width: 64ch;
  margin: 0;
  font-size: .98rem;
  line-height: 1.9;
  color: var(--mist);
}

/* ---------- 团队分工 ---------- */
.page-about .crew-grid {
  display: grid;
  grid-template-columns: 1fr;
  align-items: start;
  gap: .75rem;
  margin-top: clamp(1.5rem, 4vw, 2.3rem);
}

.page-about .crew-trigger {
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: .32rem;
  padding: 1rem 1.05rem;
  text-align: left;
  font-family: inherit;
  cursor: pointer;
  color: var(--paper);
  background: var(--hull);
  border: 1px solid var(--line);
  border-radius: var(--r-m);
  transition: border-color .2s var(--ease), background-color .2s var(--ease), transform .2s var(--ease);
}

.page-about .crew-trigger:hover,
.page-about .crew-trigger:focus-visible {
  border-color: var(--line-cyan);
  background: rgba(47, 224, 200, .07);
  transform: translateY(-2px);
}

.page-about .crew-name {
  font-size: 1.02rem;
  font-weight: 800;
  letter-spacing: -.01em;
}

.page-about .crew-sub {
  font-size: .78rem;
  line-height: 1.5;
  color: var(--mist);
}

.page-about .crew-item .accordion-body {
  padding-top: .7rem;
  padding-bottom: .2rem;
  font-size: .88rem;
  line-height: 1.82;
  color: var(--mist);
}

.page-about .crew-item .accordion-body p {
  margin: 0;
}

.page-about .crew-figure {
  margin: clamp(1.6rem, 4vw, 2.4rem) 0 0;
  border: 1px solid var(--line);
  border-radius: var(--r-l);
  background: var(--hull-deep);
  overflow: hidden;
}

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

/* ---------- 发展历程 ---------- */
.page-about .tl-figure {
  margin: clamp(1.5rem, 4vw, 2.2rem) 0 clamp(1.8rem, 5vw, 2.8rem);
  border: 1px solid var(--line);
  border-radius: var(--r-l);
  background: var(--hull-deep);
  overflow: hidden;
}

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

.page-about .tl-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(1.2rem, 4vw, 2.2rem);
}

.page-about .tl-rail-list {
  display: flex;
  flex-direction: row;
  gap: .4rem;
  margin: 0;
  padding: 0 0 .4rem;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .tl-rail-link {
  display: block;
  padding: .4rem .7rem;
  font-size: .86rem;
  letter-spacing: .08em;
  color: var(--steel);
  text-decoration: none;
  white-space: nowrap;
  border: 1px solid var(--line);
  border-radius: var(--r-pill);
  transition: color .2s var(--ease), border-color .2s var(--ease), background-color .2s var(--ease);
}

.page-about .tl-rail-link:hover,
.page-about .tl-rail-link:focus-visible {
  color: var(--cyan);
  border-color: var(--line-cyan);
  background: rgba(47, 224, 200, .08);
}

.page-about .tl-stream {
  display: flex;
  flex-direction: column;
  gap: clamp(1rem, 3vw, 1.5rem);
}

.page-about .tl-node {
  position: relative;
  padding: clamp(1.1rem, 3vw, 1.6rem);
  border: 1px solid var(--line);
  border-left: 3px solid var(--steel);
  border-radius: var(--r-m);
  background: linear-gradient(135deg, rgba(18, 41, 63, .92), rgba(13, 32, 50, .74));
  scroll-margin-top: 120px;
  transition: border-color .25s var(--ease), background-color .25s var(--ease), transform .25s var(--ease);
}

.page-about .tl-node:nth-child(1) { border-left-color: var(--steel); }
.page-about .tl-node:nth-child(2) { border-left-color: var(--teal); }
.page-about .tl-node:nth-child(3) { border-left-color: var(--cyan); }
.page-about .tl-node:nth-child(4) { border-left-color: var(--amber); }
.page-about .tl-node:nth-child(5) { border-left-color: var(--ember); }

.page-about .tl-node:hover,
.page-about .tl-node:target {
  border-top-color: var(--line-cyan);
  border-right-color: var(--line-cyan);
  border-bottom-color: var(--line-cyan);
  transform: translateX(3px);
}

.page-about .tl-year {
  display: inline-block;
  margin: 0 0 .45rem;
  font-size: 1.02rem;
  letter-spacing: .1em;
  color: var(--amber);
}

.page-about .tl-title {
  margin: 0 0 .5rem;
  font-family: var(--font-sans);
  font-size: clamp(1.06rem, 2.4vw, 1.28rem);
  font-weight: 800;
  line-height: 1.35;
  letter-spacing: -.012em;
  color: var(--paper);
}

.page-about .tl-text {
  margin: 0;
  font-size: .93rem;
  line-height: 1.9;
  color: var(--mist);
}

/* ---------- 覆盖范围 ---------- */
.page-about .cover-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(1.5rem, 4vw, 2.4rem);
  margin-top: clamp(1.6rem, 4vw, 2.4rem);
}

.page-about .cover-visual {
  position: relative;
  border: 1px solid var(--line);
  border-radius: var(--r-l);
  background: var(--hull-deep);
  overflow: hidden;
}

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

.page-about .cover-pins {
  position: absolute;
  inset: 0;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .pin {
  position: absolute;
  display: inline-flex;
  align-items: center;
  gap: .38rem;
  padding: .2rem .55rem .2rem .32rem;
  font-size: .72rem;
  line-height: 1.4;
  white-space: nowrap;
  color: var(--mist);
  background: rgba(11, 27, 43, .88);
  border: 1px solid var(--line);
  border-radius: var(--r-pill);
  transition: color .2s var(--ease), border-color .2s var(--ease), transform .2s var(--ease);
}

.page-about .pin:hover {
  color: var(--paper);
  border-color: var(--line-cyan);
  transform: translateY(-2px);
}

.page-about .pin-dot {
  flex: none;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--cyan);
  box-shadow: 0 0 0 3px rgba(47, 224, 200, .16);
}

.page-about .pin-a { left: 6%; top: 58%; }
.page-about .pin-b { left: 30%; top: 36%; }
.page-about .pin-c { left: 34%; top: 72%; }
.page-about .pin-d { left: 62%; top: 52%; }
.page-about .pin-e { left: 8%; top: 16%; }
.page-about .pin-f { left: 60%; top: 12%; }

.page-about .cover-notes {
  display: flex;
  flex-direction: column;
  gap: .85rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .cover-note {
  padding: 1.05rem 1.15rem;
  background: rgba(18, 41, 63, .7);
  border: 1px solid var(--line);
  border-left: 3px solid var(--cyan);
  border-radius: 0 var(--r-m) var(--r-m) 0;
}

.page-about .cover-note:nth-child(2) { border-left-color: var(--amber); }
.page-about .cover-note:nth-child(3) { border-left-color: var(--teal); }

.page-about .cover-note h3 {
  margin: 0 0 .35rem;
  font-size: .98rem;
  font-weight: 800;
  color: var(--paper);
}

.page-about .cover-note p {
  margin: 0;
  font-size: .9rem;
  line-height: 1.85;
  color: var(--mist);
}

/* ---------- 协作与测试 ---------- */
.page-about .partner-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(1.4rem, 4vw, 2.4rem);
  margin-top: clamp(1.6rem, 4vw, 2.4rem);
}

.page-about .partner-text {
  margin: 0;
  font-size: .98rem;
  line-height: 1.95;
  color: var(--mist);
}

.page-about .partner-list {
  display: grid;
  gap: .65rem;
  margin: 1.2rem 0 0;
  padding: 0;
  list-style: none;
}

.page-about .partner-list li {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: .8rem;
  align-items: baseline;
  padding: .8rem 1rem;
  font-size: .91rem;
  line-height: 1.75;
  color: var(--mist);
  background: rgba(18, 41, 63, .55);
  border: 1px solid var(--line-soft);
  border-radius: var(--r-s);
}

.page-about .partner-list .mono {
  font-size: .78rem;
  letter-spacing: .08em;
  color: var(--amber);
}

.page-about .test-card {
  padding: clamp(1.2rem, 3vw, 1.7rem);
  border: 1px solid var(--line-amber);
  border-radius: var(--r-l);
  background: linear-gradient(160deg, rgba(240, 180, 41, .1), rgba(11, 27, 43, .45) 62%);
}

.page-about .test-title {
  margin: 0 0 .5rem;
  font-size: clamp(1.05rem, 2.4vw, 1.22rem);
  font-weight: 800;
  color: var(--paper);
}

.page-about .test-lead {
  margin: 0 0 1rem;
  font-size: .9rem;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .test-list {
  display: grid;
  gap: .1rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .test-list li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: .4rem 1rem;
  padding: .6rem 0;
  border-bottom: 1px dashed var(--line);
  font-size: .88rem;
}

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

.page-about .test-k {
  color: var(--mist);
}

.page-about .test-v {
  color: var(--paper);
}

/* ---------- 文档维护 ---------- */
.page-about .docs-list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  margin: clamp(1.5rem, 4vw, 2.2rem) 0 0;
  padding: 0;
  list-style: none;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--r-m);
  overflow: hidden;
}

.page-about .docs-item {
  padding: clamp(1.05rem, 3vw, 1.5rem);
  background: var(--hull-deep);
}

.page-about .docs-item h3 {
  margin: 0 0 .55rem;
  font-size: 1rem;
  font-weight: 800;
  line-height: 1.4;
  color: var(--paper);
}

.page-about .docs-item p {
  margin: 0;
  font-size: .9rem;
  line-height: 1.85;
  color: var(--mist);
}

.page-about .docs-links {
  display: flex;
  flex-wrap: wrap;
  gap: .7rem;
  margin-top: clamp(1.2rem, 3vw, 1.8rem);
}

/* ---------- 结尾入口 ---------- */
.page-about .about-next {
  margin-top: clamp(1.6rem, 4vw, 2.4rem);
  padding-block: clamp(1.8rem, 5vw, 3rem);
  border-top: 1px solid var(--line-amber);
  background: linear-gradient(180deg, rgba(240, 180, 41, .07), transparent 78%);
}

.page-about .next-inner {
  display: grid;
  gap: 1.4rem;
}

.page-about .next-title {
  margin: 0 0 .6rem;
  font-family: var(--font-sans);
  font-weight: 850;
  font-size: clamp(1.3rem, 3.2vw, 1.85rem);
  line-height: 1.25;
  letter-spacing: -.015em;
  color: var(--paper);
}

.page-about .next-text {
  max-width: 62ch;
  margin: 0;
  font-size: .96rem;
  line-height: 1.9;
  color: var(--mist);
}

.page-about .next-links {
  display: flex;
  flex-wrap: wrap;
  gap: .7rem;
}

/* ---------- 响应式 ---------- */
@media (min-width: 620px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

@media (min-width: 820px) {
  .page-about .tl-layout {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: clamp(2rem, 5vw, 3.2rem);
  }

  .page-about .tl-rail {
    position: sticky;
    top: 112px;
    align-self: start;
  }

  .page-about .tl-rail-list {
    position: relative;
    flex-direction: column;
    gap: 0;
    padding: 0;
    overflow: visible;
  }

  .page-about .tl-rail-list::before {
    content: "";
    position: absolute;
    left: 5px;
    top: 10px;
    bottom: 10px;
    width: 1px;
    background: var(--line);
  }

  .page-about .tl-rail-link {
    position: relative;
    padding: .5rem .6rem .5rem 1.4rem;
    border: 0;
    border-radius: var(--r-s);
    background: transparent;
  }

  .page-about .tl-rail-link::before {
    content: "";
    position: absolute;
    left: 1px;
    top: 50%;
    width: 9px;
    height: 9px;
    margin-top: -4.5px;
    border-radius: 50%;
    background: var(--hull-deep);
    border: 1px solid var(--steel);
    transition: background-color .2s var(--ease), border-color .2s var(--ease), box-shadow .2s var(--ease);
  }

  .page-about .tl-rail-link:hover::before,
  .page-about .tl-rail-link:focus-visible::before {
    background: var(--cyan);
    border-color: var(--cyan);
    box-shadow: 0 0 0 4px rgba(47, 224, 200, .14);
  }
}

@media (min-width: 900px) {
  .page-about .cover-layout {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: center;
  }

  .page-about .partner-layout {
    grid-template-columns: minmax(0, 6fr) minmax(0, 5fr);
    align-items: start;
  }

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

  .page-about .next-inner {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: center;
  }

  .page-about .next-links {
    justify-content: flex-end;
  }
}

@media (min-width: 980px) {
  .page-about .crew-grid {
    grid-template-columns: repeat(5, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .crew-trigger,
  .page-about .tl-node,
  .page-about .pin,
  .page-about .tl-rail-link,
  .page-about .tl-rail-link::before {
    transition: none;
  }

  .page-about .crew-trigger:hover,
  .page-about .tl-node:hover,
  .page-about .tl-node:target,
  .page-about .pin:hover {
    transform: none;
  }
}
</main>