.page-about {
  --about-rail-w: 0px;
  --about-paper-ink: var(--ink);
  background: var(--navy);
  color: var(--white);
  overflow-x: hidden;
}

@media (min-width: 1180px) {
  .page-about {
    --about-rail-w: var(--rail);
  }
}

/* ---------- 左侧章节刻度 ---------- */

.page-about .about-rail {
  position: relative;
  padding: 20px var(--gutter) 0;
  background: var(--char);
  border-bottom: 1px solid var(--line);
}

.page-about .about-rail-title {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.16em;
  color: var(--amber);
  text-transform: uppercase;
}

.page-about .about-rail-list {
  list-style: none;
  margin: 0;
  padding: 0 0 10px;
  display: flex;
  gap: 18px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-rail-item {
  flex: 0 0 auto;
}

.page-about .about-rail-link {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 6px 2px;
  white-space: nowrap;
  border-bottom: 1px solid transparent;
  color: var(--grey);
  font-size: 14px;
  text-decoration: none;
  transition: color var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}

.page-about .about-rail-num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
}

.page-about .about-rail-link:hover,
.page-about .about-rail-link:focus-visible {
  color: var(--white);
  border-bottom-color: var(--amber);
}

.page-about .about-rail-link.is-current {
  color: var(--green);
  border-bottom-color: var(--green);
}

.page-about .about-rail-link:focus-visible {
  outline: 2px solid var(--green);
  outline-offset: 3px;
}

@media (min-width: 1180px) {
  .page-about .about-rail {
    position: fixed;
    top: 142px;
    left: max(16px, calc((100vw - var(--shell)) / 2 + var(--gutter)));
    width: 200px;
    z-index: 6;
    padding: 0;
    background: none;
    border-bottom: 0;
  }

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

  .page-about .about-rail-link {
    display: grid;
    grid-template-columns: 28px 1fr;
    gap: 10px;
    padding: 9px 0;
    white-space: normal;
    border-bottom: 1px solid var(--dark-line-soft);
  }

  .page-about .about-rail-link:hover,
  .page-about .about-rail-link:focus-visible,
  .page-about .about-rail-link.is-current {
    border-bottom-color: var(--line);
  }
}

/* ---------- 章节骨架 ---------- */

.page-about .about-stream {
  display: block;
}

.page-about .chapter {
  padding: clamp(56px, 9vw, 108px) 0;
}

.page-about .chapter + .chapter {
  border-top: 1px solid var(--dark-line-soft);
}

.page-about .chapter-inner {
  width: 100%;
  max-width: var(--shell);
  margin: 0 auto;
  padding-left: calc(var(--gutter) + var(--about-rail-w));
  padding-right: var(--gutter);
}

.page-about .chapter-head {
  max-width: 760px;
  margin-bottom: clamp(30px, 4.5vw, 52px);
}

.page-about .chapter-index {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.2em;
  color: var(--amber);
}

.page-about .chapter-title {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(28px, 4.6vw, 44px);
  font-weight: 600;
  line-height: 1.1;
  letter-spacing: 0.02em;
  color: var(--white);
}

.page-about .chapter-note {
  margin: 16px 0 0;
  max-width: 60ch;
  font-size: 15px;
  line-height: 1.7;
  color: var(--grey);
}

.page-about .chapter-cols {
  display: grid;
  gap: 24px;
}

.page-about .chapter-cols p {
  margin: 0;
  font-size: 16px;
  line-height: 1.75;
  color: var(--white);
}

@media (min-width: 900px) {
  .page-about .chapter-cols {
    grid-template-columns: 1fr 1fr;
    gap: 40px;
  }

  .page-about .chapter-cols > .chapter-col:nth-child(2) {
    margin-top: 38px;
  }
}

.page-about .inline-link {
  color: var(--green);
  text-decoration: none;
  border-bottom: 1px solid rgba(62, 240, 140, 0.4);
}

.page-about .inline-link:hover,
.page-about .inline-link:focus-visible {
  border-bottom-color: var(--green);
  outline: none;
}

.page-about .chapter--paper .inline-link {
  color: var(--ink);
  border-bottom-color: var(--amber);
  font-weight: 600;
}

/* ---------- 首屏 ---------- */

.page-about .chapter--hero {
  padding-top: clamp(28px, 4vw, 48px);
}

.page-about .breadcrumb {
  margin-bottom: clamp(24px, 4vw, 44px);
}

.page-about .breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
  margin: 0;
  padding: 0;
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--grey);
}

.page-about .breadcrumb-item + .breadcrumb-item::before {
  content: "/";
  margin-right: 8px;
  color: var(--line);
}

.page-about .breadcrumb-link {
  color: var(--grey);
  text-decoration: none;
}

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

.page-about .breadcrumb-item [aria-current="page"] {
  color: var(--white);
}

.page-about .hero-grid {
  display: grid;
  gap: 32px;
}

@media (min-width: 900px) {
  .page-about .hero-grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    gap: clamp(32px, 4vw, 64px);
    align-items: start;
  }
}

.page-about .hero-kicker {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.22em;
  color: var(--amber);
}

.page-about .hero-title {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(32px, 6vw, 58px);
  font-weight: 700;
  line-height: 1.06;
  letter-spacing: 0.02em;
  color: var(--white);
}

.page-about .hero-lede {
  margin: 22px 0 0;
  max-width: 56ch;
  font-size: 16px;
  line-height: 1.8;
  color: var(--white);
}

.page-about .hero-lede--sub {
  margin-top: 12px;
  font-size: 15px;
  color: var(--grey);
}

.page-about .hero-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin: clamp(28px, 4vw, 44px) 0 0;
  padding: 22px 0 0;
  border-top: 1px solid var(--line);
}

.page-about .hero-stat {
  min-width: 0;
}

.page-about .hero-stat-label {
  margin: 0;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--grey);
}

.page-about .hero-stat-value {
  margin: 8px 0 0;
  font-family: var(--font-mono);
  font-size: clamp(28px, 5vw, 44px);
  font-weight: 700;
  line-height: 1;
  color: var(--green);
}

.page-about .hero-stat-unit {
  margin-left: 4px;
  font-size: 13px;
  font-weight: 400;
  letter-spacing: 0.08em;
  color: var(--grey);
}

.page-about .hero-media {
  margin: 0;
}

/* ---------- 图片容器 ---------- */

.page-about .media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  background: var(--char);
  border: 1px solid var(--line);
}

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

.page-about .media-frame--4x3 img {
  aspect-ratio: 4 / 3;
}

.page-about .media-frame--21x9 img {
  aspect-ratio: 21 / 9;
}

.page-about .media-frame--grain::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image: repeating-linear-gradient(0deg, rgba(245, 248, 251, 0.05) 0 1px, transparent 1px 4px);
}

.page-about .media-caption {
  margin: 10px 0 0;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--grey);
}

.page-about .chapter--paper .media-caption {
  color: var(--ink-muted);
}

/* ---------- 时间线 ---------- */

.page-about .timeline {
  list-style: none;
  margin: clamp(40px, 5vw, 64px) 0 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .timeline-item {
  display: grid;
  grid-template-columns: 62px 12px minmax(0, 1fr);
  align-items: start;
  gap: 16px;
  padding: 18px 0;
  border-bottom: 1px solid var(--dark-line-soft);
}

.page-about .timeline-year {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--green);
}

.page-about .timeline-mark {
  position: relative;
  display: block;
  width: 9px;
  height: 9px;
  margin-top: 6px;
  border: 1px solid var(--amber);
  background: var(--navy);
}

.page-about .timeline-item:last-child .timeline-mark {
  background: var(--green);
  border-color: var(--green);
}

.page-about .timeline-text {
  font-size: 15px;
  line-height: 1.7;
  color: var(--white);
}

@media (min-width: 760px) {
  .page-about .timeline-item {
    grid-template-columns: 88px 16px minmax(0, 1fr);
    gap: 24px;
  }

  .page-about .timeline-year {
    font-size: 18px;
  }
}

/* ---------- 角色手风琴 ---------- */

.page-about .role-grid {
  display: grid;
  gap: 0;
  border-top: 1px solid var(--line);
}

.page-about .role-item {
  border-bottom: 1px solid var(--dark-line-soft);
}

.page-about .role-trigger {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto 20px;
  align-items: center;
  gap: 14px;
  width: 100%;
  padding: 18px 4px;
  background: none;
  border: 0;
  color: inherit;
  font: inherit;
  text-align: left;
  cursor: pointer;
  transition: background-color var(--t-fast) var(--ease);
}

.page-about .role-trigger:hover {
  background: rgba(62, 240, 140, 0.05);
}

.page-about .role-trigger:focus-visible {
  outline: 2px solid var(--green);
  outline-offset: -2px;
}

.page-about .role-name {
  font-family: var(--font-display);
  font-size: clamp(20px, 3vw, 26px);
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--white);
}

.page-about .role-hint {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--amber);
}

.page-about .role-toggle {
  position: relative;
  display: block;
  width: 16px;
  height: 16px;
}

.page-about .role-toggle::before,
.page-about .role-toggle::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  background: var(--grey);
  transform: translate(-50%, -50%);
  transition: transform var(--t-base) var(--ease), background-color var(--t-base) var(--ease);
}

.page-about .role-toggle::before {
  width: 14px;
  height: 1px;
}

.page-about .role-toggle::after {
  width: 1px;
  height: 14px;
}

.page-about .role-trigger[aria-expanded="true"] .role-toggle::after {
  transform: translate(-50%, -50%) scaleY(0);
}

.page-about .role-trigger[aria-expanded="true"] .role-toggle::before {
  background: var(--green);
}

.page-about .role-panel {
  padding: 0 4px 22px;
}

.page-about .role-panel p {
  margin: 0;
  max-width: 66ch;
  font-size: 15px;
  line-height: 1.75;
  color: var(--grey);
}

@media (min-width: 860px) {
  .page-about .role-grid {
    grid-template-columns: 1fr 1fr;
    column-gap: 44px;
    border-top: 0;
  }

  .page-about .role-item {
    border-top: 1px solid var(--line);
  }
}

.page-about .team-band {
  margin: clamp(36px, 5vw, 60px) 0 0;
}

/* ---------- 流程 ---------- */

.page-about .flow-layout {
  display: grid;
  gap: 34px;
}

@media (min-width: 980px) {
  .page-about .flow-layout {
    grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
    gap: clamp(36px, 4vw, 64px);
    align-items: start;
  }
}

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

.page-about .flow-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .flow-step {
  position: relative;
  padding: 0 0 26px 46px;
}

.page-about .flow-step::after {
  content: "";
  position: absolute;
  left: 12px;
  top: 22px;
  bottom: -2px;
  width: 1px;
  background: var(--dark-line-soft);
}

.page-about .flow-step:last-child {
  padding-bottom: 0;
}

.page-about .flow-step:last-child::after {
  content: none;
}

.page-about .flow-trigger {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: baseline;
  gap: 4px 14px;
  width: 100%;
  padding: 0;
  background: none;
  border: 0;
  color: inherit;
  font: inherit;
  text-align: left;
  cursor: pointer;
}

.page-about .flow-trigger::before {
  content: "";
  position: absolute;
  left: -40px;
  top: 6px;
  width: 13px;
  height: 13px;
  border: 1px solid var(--amber);
  background: var(--navy);
  transition: background-color var(--t-base) var(--ease), border-color var(--t-base) var(--ease), box-shadow var(--t-base) var(--ease);
}

.page-about .flow-trigger[aria-expanded="true"]::before {
  background: var(--green);
  border-color: var(--green);
  box-shadow: 0 0 0 4px rgba(62, 240, 140, 0.14);
}

.page-about .flow-trigger:focus-visible {
  outline: 2px solid var(--green);
  outline-offset: 6px;
}

.page-about .flow-num {
  grid-column: 1;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--amber);
}

.page-about .flow-name {
  grid-column: 1;
  font-family: var(--font-display);
  font-size: clamp(20px, 3vw, 27px);
  font-weight: 600;
  line-height: 1.15;
  letter-spacing: 0.02em;
  color: var(--white);
}

.page-about .flow-time {
  grid-column: 2;
  grid-row: 1 / span 2;
  align-self: center;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--grey);
  white-space: nowrap;
}

.page-about .flow-panel {
  margin-top: 12px;
  padding-left: 0;
}

.page-about .flow-panel p {
  margin: 0;
  max-width: 64ch;
  font-size: 15px;
  line-height: 1.75;
  color: var(--grey);
}

@media (max-width: 560px) {
  .page-about .flow-time {
    grid-column: 1;
    grid-row: auto;
    align-self: start;
  }
}

/* ---------- 纸白章节 ---------- */

.page-about .chapter--paper {
  background: var(--paper);
  color: var(--about-paper-ink);
  border-top-color: var(--paper-line);
}

.page-about .chapter--paper + .chapter {
  border-top-color: var(--navy-card);
}

.page-about .chapter--paper .chapter-index {
  color: var(--amber);
}

.page-about .chapter--paper .chapter-title {
  color: var(--about-paper-ink);
}

.page-about .chapter--paper .chapter-note {
  color: var(--ink-muted);
}

.page-about .block-grid {
  display: grid;
  gap: 0;
  border-top: 1px solid var(--paper-line);
}

.page-about .block-item {
  padding: 26px 0;
  border-bottom: 1px solid var(--paper-line);
}

.page-about .block-tag {
  margin: 0 0 10px;
  display: inline-block;
  padding: 3px 9px;
  border: 1px solid var(--amber);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--ink);
}

.page-about .block-title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: clamp(21px, 3vw, 27px);
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: 0.02em;
  color: var(--ink);
}

.page-about .block-text {
  margin: 0;
  max-width: 58ch;
  font-size: 15px;
  line-height: 1.75;
  color: var(--ink-muted);
}

@media (min-width: 780px) {
  .page-about .block-grid {
    grid-template-columns: 1fr 1fr;
    column-gap: 48px;
  }
}

.page-about .archive-note {
  margin-top: clamp(32px, 4vw, 48px);
  padding: 24px 22px;
  background: rgba(11, 27, 43, 0.05);
  border: 1px solid var(--paper-line);
}

.page-about .archive-note-title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--ink);
}

.page-about .archive-note-text {
  margin: 0;
  max-width: 74ch;
  font-size: 15px;
  line-height: 1.75;
  color: var(--ink-muted);
}

/* ---------- 合作数据带 ---------- */

.page-about .partner-row {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
  margin-top: clamp(34px, 4.5vw, 56px);
  border-top: 1px solid var(--line);
}

.page-about .partner-cell {
  display: flex;
  align-items: baseline;
  gap: 16px;
  padding: 20px 0;
  border-bottom: 1px solid var(--dark-line-soft);
}

.page-about .partner-num {
  font-family: var(--font-mono);
  font-size: clamp(34px, 6vw, 60px);
  font-weight: 700;
  line-height: 1;
  color: var(--green);
}

.page-about .partner-plus {
  font-size: 0.55em;
  color: var(--amber);
}

.page-about .partner-label {
  font-size: 14px;
  letter-spacing: 0.1em;
  color: var(--grey);
}

@media (min-width: 760px) {
  .page-about .partner-row {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .partner-cell {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
    padding: 26px 24px 26px 0;
    border-bottom: 0;
    border-right: 1px solid var(--dark-line-soft);
  }

  .page-about .partner-cell:last-child {
    border-right: 0;
  }
}

/* ---------- 运营与联系 ---------- */

.page-about .ops-grid {
  display: grid;
  gap: 22px;
}

@media (min-width: 940px) {
  .page-about .ops-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 28px;
    align-items: start;
  }
}

.page-about .ops-card {
  padding: 24px 22px;
  background: rgba(255, 255, 255, 0.66);
  border: 1px solid var(--paper-line);
}

.page-about .ops-card-tag {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--amber);
}

.page-about .ops-card-title {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-size: 21px;
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: 0.02em;
  color: var(--ink);
}

.page-about .ops-card-text {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--ink-muted);
}

.page-about .ops-card-text--tight {
  margin-top: 14px;
}

.page-about .ops-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .ops-item {
  display: grid;
  gap: 4px;
  padding: 10px 0;
  border-bottom: 1px solid var(--paper-line);
}

.page-about .ops-item:first-child {
  padding-top: 0;
}

.page-about .ops-item-label {
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--ink-muted);
}

.page-about .ops-item-value {
  font-size: 15px;
  line-height: 1.6;
  color: var(--ink);
  word-break: break-word;
}

.page-about .ops-item-value.num {
  font-family: var(--font-mono);
  font-size: 17px;
  letter-spacing: 0.04em;
}

.page-about .ops-item-value--link {
  text-decoration: none;
  border-bottom: 1px solid var(--amber);
}

.page-about .ops-item-value--link:hover,
.page-about .ops-item-value--link:focus-visible {
  border-bottom-color: var(--ink);
  outline: none;
}

/* ---------- 窄屏保护 ---------- */

@media (max-width: 420px) {
  .page-about .hero-stats {
    grid-template-columns: 1fr 1fr;
    gap: 18px 12px;
  }

  .page-about .flow-step {
    padding-left: 38px;
  }

  .page-about .flow-trigger::before {
    left: -32px;
  }

  .page-about .flow-step::after {
    left: 10px;
  }
}

/* ---------- 减弱动效 ---------- */

@media (prefers-reduced-motion: no-preference) {
  .page-about .hero-title,
  .page-about .hero-kicker,
  .page-about .hero-lede,
  .page-about .hero-stats,
  .page-about .hero-media {
    animation: about-rise 560ms var(--ease) both;
  }

  .page-about .hero-lede {
    animation-delay: 70ms;
  }

  .page-about .hero-stats {
    animation-delay: 140ms;
  }

  .page-about .hero-media {
    animation-delay: 110ms;
  }
}

@keyframes about-rise {
  from {
    opacity: 0;
    transform: translateY(14px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    animation: none !important;
    transition-duration: 1ms !important;
  }
}