.page-about {
  background: var(--c-ink);
  color: var(--c-paper);
  font-family: var(--font-sans);
  overflow-x: clip;
  padding-bottom: clamp(40px, 6vw, 80px);
}

.page-about .breadcrumbs {
  padding-top: clamp(14px, 2vw, 24px);
  margin: 0 0 var(--stack);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  margin-top: 0;
  background: var(--c-indigo);
  border: 1px solid var(--line-gold);
  clip-path: polygon(0 0, calc(100% - var(--radius-cut)) 0, 100% var(--radius-cut), 100% 100%, 0 100%);
  overflow: hidden;
  isolation: isolate;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background: linear-gradient(104deg, rgba(10, 24, 38, 0.95) 0%, rgba(10, 24, 38, 0.78) 44%, rgba(10, 24, 38, 0.28) 100%);
}

.page-about .hero-media {
  position: absolute;
  inset: 0;
  z-index: 0;
  width: 100%;
  height: 100%;
  max-width: 100%;
  object-fit: cover;
  opacity: 0.5;
}

.page-about .hero-copy {
  position: relative;
  z-index: 2;
  max-width: 800px;
  padding: clamp(32px, 6vw, 76px) clamp(20px, 5vw, 60px);
}

.page-about .hero-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.22em;
  color: var(--c-gold);
  padding-bottom: 6px;
  border-bottom: 1px solid var(--line-gold-strong);
}

.page-about h1 {
  margin: 22px 0 0;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(26px, 4vw, 40px);
  line-height: 1.32;
  letter-spacing: -0.01em;
  color: var(--c-paper);
}

.page-about .hero-lead {
  margin: 20px 0 0;
  max-width: 58ch;
  font-size: 16px;
  line-height: 1.85;
  color: var(--c-mist);
}

.page-about .hero-facts {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  margin: clamp(26px, 4vw, 42px) 0 0;
  background: var(--line-gold);
  border: 1px solid var(--line-gold);
}

.page-about .hero-facts .fact {
  background: rgba(10, 24, 38, 0.86);
  padding: 14px 18px;
}

.page-about .hero-facts dt {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--c-celadon);
}

.page-about .hero-facts dd {
  margin: 7px 0 0;
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--c-gold);
}

@media (min-width: 700px) {
  .page-about .hero-facts {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

/* ---------- 主栅格 ---------- */
.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--stack);
  margin-top: clamp(38px, 6.5vw, 84px);
}

.page-about .about-stream {
  display: flex;
  flex-direction: column;
  gap: clamp(42px, 6vw, 84px);
  min-width: 0;
}

@media (min-width: 960px) {
  .page-about .about-shell {
    grid-template-columns: 208px minmax(0, 1fr);
    column-gap: clamp(32px, 4.4vw, 76px);
    align-items: start;
  }
}

/* ---------- 左侧常驻索引 ---------- */
.page-about .about-rail {
  min-width: 0;
}

.page-about .rail-cap {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  color: var(--c-gold);
}

.page-about .rail-list {
  display: flex;
  gap: 10px;
  margin: 0;
  padding: 0 0 6px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
  scrollbar-color: var(--c-gold) transparent;
}

.page-about .rail-link {
  display: flex;
  align-items: baseline;
  gap: 9px;
  white-space: nowrap;
  padding: 9px 13px;
  text-decoration: none;
  color: var(--c-mist);
  background: rgba(19, 39, 67, 0.55);
  border: 1px solid var(--line-mist);
  font-size: 13px;
  transition: color var(--t-fast) var(--ease-out), border-color var(--t-fast) var(--ease-out);
}

.page-about .rail-num {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--c-gold);
}

.page-about .rail-link:hover,
.page-about .rail-link:focus-visible {
  color: var(--c-paper);
  border-color: var(--line-gold-strong);
}

.page-about .rail-link:focus-visible {
  outline: 2px solid var(--c-gold);
  outline-offset: 2px;
}

@media (min-width: 960px) {
  .page-about .about-rail {
    position: sticky;
    top: 132px;
  }

  .page-about .rail-list {
    flex-direction: column;
    gap: 0;
    padding: 0;
    overflow: visible;
    border-left: 1px solid var(--line-gold);
  }

  .page-about .rail-link {
    padding: 11px 0 11px 16px;
    margin-left: -1px;
    border: 0;
    border-left: 2px solid transparent;
    background: none;
  }

  .page-about .rail-link:hover,
  .page-about .rail-link:focus-visible {
    border-left-color: var(--line-gold-strong);
  }

  .page-about .rail-link[data-current] {
    border-left-color: var(--c-gold);
    color: var(--c-paper);
    background: linear-gradient(90deg, rgba(200, 164, 74, 0.16), rgba(200, 164, 74, 0) 82%);
  }
}

/* ---------- 章节通用 ---------- */
.page-about .about-sec {
  scroll-margin-top: 124px;
  min-width: 0;
}

.page-about .sec-head {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: clamp(22px, 3vw, 34px);
}

.page-about .sec-num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.24em;
  color: var(--c-celadon);
}

.page-about .sec-title {
  margin: 0;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(21px, 2.9vw, 30px);
  line-height: 1.36;
  letter-spacing: -0.01em;
  color: var(--c-paper);
}

.page-about .sec-lead {
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--c-mist);
}

/* ---------- 沿革时间轴 ---------- */
.page-about .origin-track {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .origin-node {
  position: relative;
  padding: 24px 22px 26px;
  background: var(--c-indigo);
  clip-path: polygon(0 0, calc(100% - 18px) 0, 100% 18px, 100% 100%, 0 100%);
}

.page-about .origin-node::before {
  content: "";
  display: block;
  width: 34px;
  height: 2px;
  margin-bottom: 18px;
  background: var(--line-gold-strong);
}

.page-about .origin-node--now {
  background: linear-gradient(152deg, rgba(14, 53, 50, 0.96) 0%, rgba(19, 39, 67, 0.98) 100%);
}

.page-about .origin-node--now::before {
  width: 64px;
  background: var(--c-gold);
}

.page-about .node-tag {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--c-gold);
  margin-bottom: 12px;
}

.page-about .node-tag--live::before {
  content: "";
  display: inline-block;
  width: 6px;
  height: 6px;
  margin-right: 9px;
  vertical-align: middle;
  background: var(--c-coral);
  transform: rotate(45deg);
}

.page-about .origin-node h3 {
  margin: 0 0 10px;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: 17px;
  line-height: 1.55;
  color: var(--c-paper);
}

.page-about .origin-node p {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--c-mist);
}

@media (min-width: 800px) {
  .page-about .origin-track {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
  }

  .page-about .origin-node {
    padding: 26px 24px 30px;
  }
}

/* ---------- 价值主张 ---------- */
.page-about .principle-list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about .principle {
  background: var(--c-indigo);
  border-left: 2px solid var(--line-gold);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 18px), calc(100% - 18px) 100%, 0 100%);
}

.page-about .principle > summary {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 18px 22px;
  cursor: pointer;
  list-style: none;
  transition: background var(--t-fast) var(--ease-out);
}

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

.page-about .principle > summary:hover {
  background: rgba(200, 164, 74, 0.06);
}

.page-about .principle > summary:focus-visible {
  outline: 2px solid var(--c-gold);
  outline-offset: -2px;
}

.page-about .pr-index {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--c-gold);
}

.page-about .pr-title {
  flex: 1 1 auto;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: 16px;
  line-height: 1.6;
  color: var(--c-paper);
}

.page-about .pr-toggle {
  position: relative;
  flex: 0 0 auto;
  width: 14px;
  height: 14px;
}

.page-about .pr-toggle::before,
.page-about .pr-toggle::after {
  content: "";
  position: absolute;
  background: var(--c-gold);
  transition: transform var(--t-mid) var(--ease-out);
}

.page-about .pr-toggle::before {
  top: 6px;
  left: 0;
  width: 14px;
  height: 2px;
}

.page-about .pr-toggle::after {
  top: 0;
  left: 6px;
  width: 2px;
  height: 14px;
}

.page-about .principle[open] .pr-toggle::after {
  transform: scaleY(0);
}

.page-about .pr-body {
  padding: 0 22px 24px;
}

.page-about .pr-body p {
  margin: 0;
  max-width: 68ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--c-mist);
}

/* ---------- 审校机制 ---------- */
.page-about .review-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 22px;
}

.page-about .review-figure {
  position: relative;
  margin: 0;
  background: var(--c-jade);
  clip-path: polygon(0 0, calc(100% - 22px) 0, 100% 22px, 100% 100%, 0 100%);
  overflow: hidden;
}

.page-about .review-figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  aspect-ratio: 9 / 7;
  object-fit: cover;
  opacity: 0.9;
}

.page-about .review-figure figcaption {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 30px 18px 14px;
  background: linear-gradient(0deg, rgba(10, 24, 38, 0.94), rgba(10, 24, 38, 0));
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.7;
  letter-spacing: 0.04em;
  color: var(--c-paper);
}

.page-about .review-copy {
  display: flex;
  flex-direction: column;
  gap: 16px;
  justify-content: center;
}

.page-about .review-copy p {
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--c-mist);
}

@media (min-width: 820px) {
  .page-about .review-split {
    grid-template-columns: minmax(0, 0.88fr) minmax(0, 1fr);
    gap: clamp(22px, 3.2vw, 40px);
    align-items: stretch;
  }
}

.page-about .role-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin-top: clamp(22px, 3vw, 34px);
}

.page-about .role {
  background: var(--c-jade);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 16px), calc(100% - 16px) 100%, 0 100%);
}

.page-about .role > summary {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding: 18px 20px 16px;
  cursor: pointer;
  list-style: none;
  transition: background var(--t-fast) var(--ease-out);
}

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

.page-about .role > summary:hover {
  background: rgba(200, 164, 74, 0.08);
}

.page-about .role > summary:focus-visible {
  outline: 2px solid var(--c-gold);
  outline-offset: -2px;
}

.page-about .role-name {
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: 15px;
  line-height: 1.6;
  color: var(--c-paper);
}

.page-about .role-count {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--c-gold);
}

.page-about .role-body {
  padding: 0 20px 22px;
  border-top: 1px solid var(--line-celadon);
  padding-top: 16px;
  margin: 0 20px 22px;
  padding-left: 0;
  padding-right: 0;
  padding-bottom: 0;
}

.page-about .role-body p {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--c-mist);
}

@media (min-width: 780px) {
  .page-about .role-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
  }
}

/* ---------- 中段横向色带 ---------- */
.page-about .about-band {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 24px;
  margin: 0;
  padding: 26px 0 22px;
  border-top: 1px solid var(--line-gold);
  border-bottom: 1px solid var(--line-gold);
  background: linear-gradient(90deg, rgba(200, 164, 74, 0.1), rgba(200, 164, 74, 0) 72%);
}

.page-about .about-band::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 7px;
  background-image: repeating-linear-gradient(90deg, var(--line-gold-strong) 0 1px, transparent 1px 22px);
  pointer-events: none;
}

.page-about .band-text {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.8;
  letter-spacing: 0.06em;
  color: var(--c-gold-soft);
}

.page-about .band-meta {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--c-celadon);
}

/* ---------- 服务网络 ---------- */
.page-about .network-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 24px;
}

.page-about .network-figure {
  margin: 0;
}

.page-about .network-figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  clip-path: polygon(0 0, calc(100% - 20px) 0, 100% 20px, 100% 100%, 20px 100%, 0 calc(100% - 20px));
}

.page-about .channel-list {
  display: flex;
  flex-direction: column;
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line-mist);
}

.page-about .channel-list li {
  padding: 20px 0 22px;
  border-bottom: 1px solid var(--line-mist);
}

.page-about .channel-num {
  display: block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--c-celadon);
  margin-bottom: 9px;
}

.page-about .channel-list h3 {
  margin: 0 0 8px;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: 16px;
  line-height: 1.55;
  color: var(--c-paper);
}

.page-about .channel-list p {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--c-mist);
}

@media (min-width: 820px) {
  .page-about .network-split {
    grid-template-columns: minmax(0, 0.74fr) minmax(0, 1fr);
    gap: clamp(24px, 3.4vw, 52px);
    align-items: center;
  }
}

/* ---------- 协作生态 ---------- */
.page-about .partner-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
}

.page-about .partner-col {
  position: relative;
  padding: 22px 22px 24px;
  background: var(--c-indigo);
  border-top: 2px solid var(--line-gold);
  clip-path: polygon(0 0, 100% 0, 100% 100%, 18px 100%, 0 calc(100% - 18px));
}

.page-about .partner-index {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--c-celadon);
  margin-bottom: 12px;
}

.page-about .partner-col h3 {
  margin: 0 0 10px;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: 16px;
  line-height: 1.6;
  color: var(--c-paper);
}

.page-about .partner-col p {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--c-mist);
}

@media (min-width: 780px) {
  .page-about .partner-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

/* ---------- 资质与站点 ---------- */
.page-about .cred-block {
  padding: clamp(20px, 3vw, 30px) clamp(20px, 3vw, 34px);
  background: var(--c-wine);
  clip-path: polygon(0 0, calc(100% - 26px) 0, 100% 26px, 100% 100%, 0 100%);
}

.page-about .cred-list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  margin: 0;
}

.page-about .cred-item {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 16px;
  padding: 15px 0;
  border-bottom: 1px solid rgba(243, 237, 225, 0.16);
}

.page-about .cred-item:last-child {
  border-bottom: none;
}

.page-about .cred-item dt {
  flex: 0 0 auto;
  min-width: 88px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--c-gold-soft);
}

.page-about .cred-item dd {
  flex: 1 1 220px;
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--c-paper);
  word-break: break-word;
}

@media (min-width: 720px) {
  .page-about .cred-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: clamp(24px, 3vw, 44px);
  }

  .page-about .cred-item:nth-last-child(2) {
    border-bottom: none;
  }

  .page-about .cred-item--wide {
    grid-column: 1 / -1;
    border-bottom: none;
  }
}

.page-about .cred-note {
  margin: 20px 0 0;
  max-width: 68ch;
  font-size: 14px;
  line-height: 1.85;
  color: var(--c-mist);
}

.page-about .cred-note a {
  color: var(--c-gold);
  text-decoration: none;
  border-bottom: 1px solid var(--line-gold-strong);
  transition: color var(--t-fast) var(--ease-out), border-color var(--t-fast) var(--ease-out);
}

.page-about .cred-note a:hover,
.page-about .cred-note a:focus-visible {
  color: var(--c-gold-soft);
  border-bottom-color: var(--c-gold-soft);
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition-duration: 1ms !important;
  }
}