.page-about {
  display: block;
  background: var(--ink);
  color: var(--text);
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */
.page-about__hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  padding: clamp(26px, 6vw, 56px) 0 clamp(34px, 7vw, 68px);
  background:
    radial-gradient(130% 100% at 10% -10%, #16223c 0%, #0a1020 46%, var(--ink) 100%);
  border-bottom: 1px solid var(--orbit);
}

.page-about__hero-media {
  position: absolute;
  inset: 0;
  z-index: -2;
}

.page-about__hero-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.26;
}

.page-about__hero-veil {
  position: absolute;
  inset: 0;
  z-index: -1;
  background:
    linear-gradient(180deg, rgba(7, 10, 20, 0.42) 0%, rgba(7, 10, 20, 0.8) 58%, rgba(7, 10, 20, 0.97) 100%);
}

.page-about__hero-inner {
  position: relative;
}

.page-about .crumb-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}

.page-about .crumb-link {
  color: var(--text-soft);
  text-decoration: none;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  transition: color 0.3s var(--ease);
}

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

.page-about .crumb-current {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--flame);
}

.page-about__hero .eyebrow {
  margin: clamp(26px, 5vw, 46px) 0 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--nebula);
  text-transform: uppercase;
}

.page-about__hero h1 {
  max-width: 880px;
  margin: 16px 0 0;
  line-height: 1.14;
}

.page-about__hero .lede {
  max-width: 60ch;
  margin: 20px 0 0;
  color: var(--text-soft);
  font-size: clamp(15px, 2.4vw, 17px);
  line-height: 1.9;
}

.page-about__facts {
  list-style: none;
  margin: clamp(30px, 5vw, 48px) 0 0;
  padding: 22px 0 0;
  border-top: 1px solid var(--orbit);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px 18px;
}

.page-about__fact {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about__fact-num {
  font-family: var(--font-mono);
  font-size: clamp(24px, 5.4vw, 34px);
  font-weight: 700;
  line-height: 1;
  color: var(--cyan);
  letter-spacing: 0.01em;
}

.page-about__fact-label {
  font-size: 12.5px;
  letter-spacing: 0.04em;
  color: var(--text-dim);
}

.page-about__toc {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 10px;
  margin-top: clamp(26px, 4vw, 38px);
}

.page-about__toc-link {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.03em;
  color: var(--text-soft);
  text-decoration: none;
  padding: 7px 15px;
  border: 1px solid var(--orbit);
  border-radius: 999px;
  background: rgba(16, 23, 40, 0.72);
  transition: color 0.3s var(--ease), background 0.3s var(--ease), border-color 0.3s var(--ease);
}

.page-about__toc-link:hover,
.page-about__toc-link:focus-visible {
  color: var(--ink);
  background: var(--cyan);
  border-color: var(--cyan);
}

.page-about__toc-link.is-current {
  color: var(--ink);
  background: var(--flame);
  border-color: var(--flame);
}

/* ---------- 章节骨架 ---------- */
.page-about__chapter {
  position: relative;
  padding: clamp(48px, 9vw, 96px) 0;
  border-bottom: 1px solid rgba(30, 39, 64, 0.6);
}

.page-about__chapter--last {
  border-bottom: 0;
  padding-bottom: clamp(60px, 10vw, 118px);
}

.page-about__chapter-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 24px;
}

.page-about__rail {
  display: flex;
  align-items: center;
  gap: 14px;
  position: relative;
}

.page-about__node {
  flex: 0 0 auto;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--nebula);
  box-shadow: 0 0 0 5px rgba(123, 92, 255, 0.15), 0 0 20px rgba(123, 92, 255, 0.6);
}

.page-about .section-num {
  display: block;
  line-height: 1;
}

.page-about__rail .sidenote--vertical {
  display: none;
}

.page-about__body {
  min-width: 0;
}

.page-about__chapter .section-head {
  margin-bottom: clamp(22px, 3.4vw, 34px);
}

.page-about__chapter .section-head .lede {
  max-width: 62ch;
  margin: 14px 0 0;
  color: var(--text-soft);
  font-size: 16px;
  line-height: 1.9;
}

.page-about__chapter .title-md {
  margin: 0 0 10px;
}

/* ---------- 四条准则 ---------- */
.page-about__principles {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
}

.page-about .paper-card {
  padding: 26px 22px;
  border-radius: var(--r-lg);
}

.page-about .paper-card p {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.9;
}

/* ---------- 历程 ---------- */
.page-about__timeline-figure {
  margin: 0 0 clamp(30px, 5vw, 46px);
}

.page-about .figure-media {
  border-radius: var(--r-lg);
  overflow: hidden;
  border: 1px solid var(--orbit);
  background:
    radial-gradient(90% 120% at 20% 0%, rgba(123, 92, 255, 0.22), transparent 62%),
    linear-gradient(160deg, #131c31 0%, #0a1020 100%);
}

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

.page-about .figure-caption {
  margin: 12px 0 0;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.7;
  letter-spacing: 0.02em;
  color: var(--text-dim);
}

.page-about__timeline {
  position: relative;
  padding-left: 28px;
}

.page-about__timeline::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 6px;
  bottom: 6px;
  width: 2px;
  border-radius: 2px;
  background: linear-gradient(180deg, rgba(123, 92, 255, 0.75) 0%, rgba(41, 216, 232, 0.4) 62%, rgba(41, 216, 232, 0) 100%);
}

.page-about__milestone {
  position: relative;
  padding-bottom: 22px;
}

.page-about__milestone:last-child {
  padding-bottom: 0;
}

.page-about__milestone::before {
  content: "";
  position: absolute;
  left: -28px;
  top: 7px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--ink);
  border: 2px solid var(--nebula);
  box-shadow: 0 0 14px rgba(123, 92, 255, 0.65);
  transition: border-color 0.3s var(--ease), box-shadow 0.3s var(--ease);
}

.page-about__milestone[open]::before {
  border-color: var(--flame);
  box-shadow: 0 0 16px rgba(255, 107, 44, 0.6);
}

.page-about__milestone summary {
  list-style: none;
  cursor: pointer;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px 14px;
  padding: 2px 26px 2px 0;
  position: relative;
}

.page-about__milestone summary::-webkit-details-marker {
  display: none;
}

.page-about__stage {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.1em;
  color: var(--cyan);
  white-space: nowrap;
}

.page-about__milestone-title {
  font-size: 17.5px;
  font-weight: 700;
  color: var(--text);
  transition: color 0.3s var(--ease);
}

.page-about__milestone[open] .page-about__milestone-title {
  color: var(--flame);
}

.page-about__milestone-plus {
  position: absolute;
  right: 0;
  top: 50%;
  width: 14px;
  height: 14px;
  margin-top: -7px;
}

.page-about__milestone-plus::before,
.page-about__milestone-plus::after {
  content: "";
  position: absolute;
  background: var(--text-dim);
  transition: transform 0.32s var(--ease), background 0.3s var(--ease);
}

.page-about__milestone-plus::before {
  left: 0;
  top: 6px;
  width: 14px;
  height: 2px;
}

.page-about__milestone-plus::after {
  left: 6px;
  top: 0;
  width: 2px;
  height: 14px;
}

.page-about__milestone[open] .page-about__milestone-plus::after {
  transform: scaleY(0);
}

.page-about__milestone[open] .page-about__milestone-plus::before {
  background: var(--flame);
}

.page-about__milestone-body {
  padding: 12px 0 0;
}

.page-about__milestone-body p {
  margin: 0;
  max-width: 66ch;
  font-size: 15.5px;
  line-height: 1.9;
  color: var(--text-soft);
}

/* ---------- 团队与流程 ---------- */
.page-about__team {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about__role {
  position: relative;
  padding: 22px 20px;
  border: 1px solid var(--orbit);
  border-radius: var(--r-lg);
  background: linear-gradient(165deg, rgba(16, 23, 40, 0.96) 0%, rgba(10, 16, 32, 0.96) 100%);
  transition: border-color 0.35s var(--ease), transform 0.35s var(--ease), box-shadow 0.35s var(--ease);
}

.page-about__role:hover,
.page-about__role:focus-within {
  border-color: var(--cyan);
  transform: translateY(-3px);
  box-shadow: 0 12px 30px rgba(41, 216, 232, 0.12);
}

.page-about__role-num {
  display: block;
  font-family: var(--font-mono);
  font-size: 30px;
  font-weight: 700;
  line-height: 1;
  color: var(--nebula);
  text-shadow: 0 0 22px rgba(123, 92, 255, 0.55);
}

.page-about__role .title-md {
  margin: 12px 0 8px;
  font-size: 18px;
}

.page-about__role p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--text-soft);
}

.page-about__flow-grid {
  margin-top: clamp(34px, 5vw, 54px);
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 30px;
}

.page-about__flow-title {
  margin: 0 0 18px;
}

.page-about__flow {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
}

.page-about__flow-step {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 8px;
  padding: 18px;
  border: 1px solid rgba(30, 39, 64, 0.95);
  border-left: 3px solid var(--cyan);
  border-radius: var(--r-md);
  background: rgba(16, 23, 40, 0.7);
  transition: border-left-color 0.3s var(--ease), background 0.3s var(--ease);
}

.page-about__flow-step:hover {
  border-left-color: var(--flame);
  background: rgba(20, 29, 50, 0.88);
}

.page-about__flow-num {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.16em;
  color: var(--flame);
}

.page-about__flow-step strong {
  display: block;
  margin-bottom: 6px;
  font-size: 16px;
  color: var(--text);
}

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

.page-about__flow-figure {
  margin: 0;
}

/* ---------- 协作与认可 ---------- */
.page-about__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(26px, 4vw, 34px);
}

/* ---------- 主体与备案 ---------- */
.page-about__info-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about__info-item {
  padding: 20px 20px;
  border: 1px solid var(--orbit);
  border-radius: var(--r-lg);
  background: rgba(16, 23, 40, 0.82);
}

.page-about__info-label {
  display: block;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.16em;
  color: var(--text-dim);
}

.page-about__info-value {
  margin: 10px 0 0;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--text);
  word-break: break-word;
}

.page-about__contact-note {
  margin: 22px 0 0;
  max-width: 68ch;
  padding: 16px 18px;
  border-radius: var(--r-md);
  border: 1px dashed rgba(123, 92, 255, 0.45);
  background: rgba(123, 92, 255, 0.07);
  font-size: 14.5px;
  line-height: 1.9;
  color: var(--text-soft);
}

/* ---------- 平板 ---------- */
@media (min-width: 720px) {
  .page-about__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about__principles {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px;
  }

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

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

  .page-about__flow-step {
    grid-template-columns: 96px minmax(0, 1fr);
    gap: 16px;
    align-items: start;
  }
}

/* ---------- 桌面：非对称编辑部网格 + 纵向轨道 ---------- */
@media (min-width: 960px) {
  .page-about__chapter-grid {
    grid-template-columns: 200px minmax(0, 1fr);
    gap: 0 56px;
  }

  .page-about__rail {
    flex-direction: column;
    align-items: flex-start;
    gap: 20px;
    padding-top: 8px;
  }

  .page-about__rail::before {
    content: "";
    position: absolute;
    left: 5px;
    top: 30px;
    bottom: -110px;
    width: 2px;
    background: linear-gradient(180deg, rgba(123, 92, 255, 0.6) 0%, rgba(41, 216, 232, 0.22) 58%, rgba(41, 216, 232, 0) 100%);
  }

  .page-about__chapter--last .page-about__rail::before {
    bottom: 0;
    background: linear-gradient(180deg, rgba(123, 92, 255, 0.6) 0%, rgba(41, 216, 232, 0) 100%);
  }

  .page-about__rail .sidenote--vertical {
    display: inline-block;
    writing-mode: vertical-rl;
    font-family: var(--font-mono);
    font-size: 12px;
    letter-spacing: 0.26em;
    color: var(--text-dim);
    margin-top: 6px;
  }

  .page-about__team {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

  .page-about__flow-grid {
    grid-template-columns: minmax(0, 1fr) 340px;
    gap: 46px;
    align-items: start;
  }
}

/* ---------- 宽屏微调 ---------- */
@media (min-width: 1200px) {
  .page-about__hero h1 {
    font-size: clamp(40px, 4vw, 62px);
  }

  .page-about__chapter-grid {
    grid-template-columns: 220px minmax(0, 1fr);
    gap: 0 72px;
  }
}

/* ---------- 降低动效偏好 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about__role,
  .page-about__flow-step,
  .page-about__toc-link,
  .page-about__milestone-title,
  .page-about__milestone-plus::before,
  .page-about__milestone-plus::after {
    transition: none;
  }

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