.page-about {
  --about-line: rgba(22, 38, 43, .14);
  --about-line-strong: rgba(22, 38, 43, .30);
  --about-gutter: clamp(18px, 4vw, 40px);
  background: var(--paper);
  color: var(--on-light);
  overflow-x: hidden;
}

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

.page-about .media {
  position: relative;
  overflow: hidden;
  margin: 0;
  background: var(--ink-800);
  border: 1px solid var(--about-line);
}

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

.page-about .media-overlay {
  display: block;
  padding: 12px 14px;
  font-size: 13.5px;
  line-height: 1.65;
  color: var(--on-dark);
  background: linear-gradient(180deg, rgba(6, 26, 31, .72), var(--ink-900));
  border-top: 1px solid var(--line-dark);
}

/* ---------- 章节标题与引导 ---------- */
.page-about .section-title {
  position: relative;
  margin: 10px 0 0;
  padding-left: 16px;
  font-family: var(--font-display);
  font-size: clamp(22px, 4.8vw, 34px);
  line-height: 1.16;
  font-weight: 800;
  letter-spacing: -.01em;
  color: var(--ink-800);
}

.page-about .section-title::before {
  content: "";
  position: absolute;
  left: 0;
  top: .16em;
  width: 4px;
  height: .88em;
  background: var(--brand);
  clip-path: polygon(0 0, 100% 0, 100% 72%, 0 100%);
}

.page-about .eyebrow {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--stone);
}

.page-about .section-head {
  max-width: 62ch;
}

.page-about .section-lead {
  margin: 14px 0 0;
  font-size: 16px;
  line-height: 1.8;
  color: var(--stone);
}

.page-about .about-body {
  margin-top: 16px;
  font-size: 16.5px;
  line-height: 1.85;
  color: var(--on-light);
}

.page-about .about-body p {
  margin: 0 0 1.05em;
}

.page-about .about-body p:last-child {
  margin-bottom: 0;
}

.page-about .about-body strong {
  color: var(--ink-800);
  font-weight: 700;
}

/* ---------- 首屏 ---------- */
.page-about .about-masthead {
  position: relative;
  overflow: hidden;
  padding-top: 26px;
  padding-bottom: 46px;
}

.page-about .about-masthead::before {
  content: "";
  position: absolute;
  top: -26%;
  right: -24%;
  width: 74%;
  aspect-ratio: 1 / 1;
  background: var(--mist);
  clip-path: polygon(0 0, 100% 0, 100% 100%, 26% 100%);
  pointer-events: none;
  z-index: 0;
}

.page-about .about-masthead::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 1px;
  background: var(--about-line-strong);
}

.page-about .about-masthead .shell {
  position: relative;
  z-index: 1;
}

.page-about .about-masthead h1 {
  position: relative;
  margin: 14px 0 0;
  padding-left: 18px;
  max-width: 20ch;
  font-family: var(--font-display);
  font-size: clamp(29px, 7.2vw, 54px);
  line-height: 1.1;
  font-weight: 900;
  letter-spacing: -.02em;
  color: var(--ink-900);
}

.page-about .about-masthead h1::before {
  content: "";
  position: absolute;
  left: 0;
  top: .14em;
  width: 4px;
  height: .92em;
  background: var(--brand);
  clip-path: polygon(0 0, 100% 0, 100% 70%, 0 100%);
}

.page-about .about-lede {
  margin: 20px 0 0;
  max-width: 60ch;
  font-family: var(--font-serif);
  font-size: clamp(16px, 2.4vw, 19px);
  line-height: 1.78;
  font-weight: 600;
  color: var(--ink-800);
}

.page-about .about-facts {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--about-line-strong);
  border: 1px solid var(--about-line-strong);
}

.page-about .about-facts > li {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 15px 16px;
  background: var(--paper);
}

.page-about .about-fact-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(23px, 5vw, 34px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--ink-900);
}

.page-about .about-fact-lbl {
  font-size: 12.5px;
  letter-spacing: .05em;
  color: var(--stone);
}

/* ---------- 缘起 ---------- */
.page-about .about-origin-grid {
  display: grid;
  gap: 22px;
}

.page-about .about-side {
  padding-left: 14px;
  border-left: 1px solid var(--about-line-strong);
}

.page-about .about-side-label {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--brand);
}

.page-about .about-side-note {
  margin: 0;
  font-family: var(--font-serif);
  font-size: 14px;
  line-height: 1.75;
  color: var(--stone);
}

/* ---------- 团队 ---------- */
.page-about .about-team-media {
  margin: 26px 0 0;
}

.page-about .about-team-list {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  border-bottom: 1px solid var(--about-line);
}

.page-about .about-team-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  grid-template-areas:
    "name num"
    "track track"
    "desc desc";
  align-items: center;
  gap: 9px 14px;
  padding: 16px 12px;
  border-top: 1px solid var(--about-line);
  transition: background-color .18s ease;
}

.page-about .about-team-row:hover {
  background: var(--mist);
}

.page-about .about-team-name {
  grid-area: name;
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 800;
  letter-spacing: -.01em;
  color: var(--ink-800);
}

.page-about .about-team-track {
  grid-area: track;
  position: relative;
  display: block;
  height: 8px;
  background: rgba(22, 38, 43, .09);
  overflow: hidden;
}

.page-about .about-team-bar {
  display: block;
  height: 100%;
  width: var(--w, 0%);
  background: var(--c, var(--brand));
  transition: width .5s ease;
}

.page-about .about-team-num {
  grid-area: num;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 26px;
  font-weight: 700;
  line-height: 1;
  color: var(--ink-900);
}

.page-about .about-team-desc {
  grid-area: desc;
  margin: 0;
  font-size: 14px;
  line-height: 1.72;
  color: var(--stone);
  transition: color .18s ease;
}

.page-about .about-team-row:hover .about-team-desc {
  color: var(--ink-800);
}

/* ---------- 核对流程 ---------- */
.page-about .about-check {
  background: var(--mist);
  border-top: 1px solid rgba(16, 200, 165, .28);
  border-bottom: 1px solid rgba(16, 200, 165, .28);
}

.page-about .about-steps {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: rgba(16, 200, 165, .32);
  border: 1px solid rgba(16, 200, 165, .32);
}

.page-about .about-step {
  display: grid;
  grid-template-columns: 54px minmax(0, 1fr);
  gap: 4px 14px;
  padding: 20px 16px;
  background: var(--mist);
  transition: background-color .18s ease;
}

.page-about .about-step--fix {
  background: rgba(255, 122, 26, .1);
}

.page-about .about-step--fix:hover {
  background: rgba(255, 122, 26, .16);
}

.page-about .about-step-idx {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 26px;
  font-weight: 700;
  line-height: 1;
  color: var(--brand);
}

.page-about .about-step--fix .about-step-idx {
  color: var(--live);
}

.page-about .about-step-title {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 800;
  letter-spacing: -.01em;
  color: var(--ink-800);
}

.page-about .about-step-body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--on-light);
  opacity: .82;
}

.page-about .about-callout {
  margin-top: 24px;
  background: rgba(255, 255, 255, .55);
}

.page-about .about-callout p {
  margin: 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--ink-800);
}

/* ---------- 发展历程（深色） ---------- */
.page-about .about-timeline {
  position: relative;
  background: var(--ink-900);
  color: var(--on-dark);
  overflow: hidden;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: repeating-linear-gradient(118deg, rgba(124, 242, 196, .055) 0 1px, transparent 1px 11px);
  pointer-events: none;
}

.page-about .about-timeline .shell {
  position: relative;
  z-index: 1;
}

.page-about .about-timeline .section-title {
  color: var(--on-dark);
}

.page-about .about-timeline .eyebrow {
  color: var(--brand-soft);
}

.page-about .about-timeline .section-lead {
  color: rgba(234, 246, 242, .72);
}

.page-about .about-timeline-media {
  margin: 26px 0 0;
  border-color: var(--line-dark);
}

.page-about .about-timeline-media .media-overlay {
  background: linear-gradient(180deg, rgba(6, 26, 31, .6), var(--ink-900));
  border-top-color: var(--line-dark);
}

.page-about .about-tl-rail {
  display: none;
}

.page-about .about-tl {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
  align-items: start;
}

.page-about .about-tl > li {
  list-style: none;
}

.page-about .about-tl-details {
  display: block;
}

.page-about .about-tl-node {
  list-style: none;
  cursor: pointer;
  display: grid;
  grid-template-columns: 12px minmax(0, 1fr);
  grid-template-areas:
    "dot year"
    "dot name";
  align-items: center;
  gap: 2px 10px;
  padding: 16px 14px 14px;
  background: rgba(124, 242, 196, .05);
  border: 1px solid var(--line-dark);
  border-top: 2px solid var(--brand);
  transition: background-color .18s ease, border-color .18s ease;
}

.page-about .about-tl-node::-webkit-details-marker {
  display: none;
}

.page-about .about-tl-node::marker {
  content: "";
}

.page-about .about-tl-node:hover {
  background: rgba(124, 242, 196, .11);
}

.page-about .about-tl-dot {
  grid-area: dot;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--brand);
  box-shadow: 0 0 0 3px rgba(16, 200, 165, .22);
  transition: background-color .18s ease, box-shadow .18s ease;
}

.page-about .about-tl-year {
  grid-area: year;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 26px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.01em;
  color: var(--brand-soft);
}

.page-about .about-tl-name {
  grid-area: name;
  font-size: 13.5px;
  letter-spacing: .04em;
  color: rgba(234, 246, 242, .72);
}

.page-about .about-tl-details[open] .about-tl-node {
  background: rgba(255, 210, 51, .09);
  border-top-color: var(--data);
  border-bottom-color: transparent;
}

.page-about .about-tl-details[open] .about-tl-dot {
  background: var(--data);
  box-shadow: 0 0 0 3px rgba(255, 210, 51, .24);
}

.page-about .about-tl-details[open] .about-tl-year {
  color: var(--data);
}

.page-about .about-tl-panel {
  padding: 14px;
  background: var(--ink-800);
  border: 1px solid var(--line-dark);
  border-top: 1px solid var(--line-soft);
  font-size: 14.5px;
  line-height: 1.76;
  color: rgba(234, 246, 242, .84);
}

.page-about .about-tl-panel p {
  margin: 0;
}

/* ---------- 合作生态 ---------- */
.page-about .about-partners-grid {
  display: grid;
  gap: 26px;
}

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

.page-about .about-partner-list {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
}

.page-about .about-partner-item {
  padding: 18px 0;
  border-top: 1px solid var(--about-line);
}

.page-about .about-partner-item:last-child {
  border-bottom: 1px solid var(--about-line);
}

.page-about .about-partner-item p {
  margin: 10px 0 0;
  font-size: 15px;
  line-height: 1.78;
  color: var(--stone);
}

/* ---------- 内容标准（折叠） ---------- */
.page-about .about-fold {
  margin-top: 26px;
  border-top: 1px solid var(--about-line-strong);
}

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

.page-about .about-fold-head {
  list-style: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 18px 4px;
  font-family: var(--font-display);
  font-size: 16.5px;
  font-weight: 800;
  letter-spacing: -.01em;
  color: var(--ink-800);
  transition: color .16s ease;
}

.page-about .about-fold-head::-webkit-details-marker {
  display: none;
}

.page-about .about-fold-head::marker {
  content: "";
}

.page-about .about-fold-head:hover {
  color: var(--brand);
}

.page-about .about-fold-mark {
  position: relative;
  flex: 0 0 16px;
  width: 16px;
  height: 16px;
  border: 1px solid var(--about-line-strong);
}

.page-about .about-fold-mark::before,
.page-about .about-fold-mark::after {
  content: "";
  position: absolute;
  background: currentColor;
}

.page-about .about-fold-mark::before {
  left: 3px;
  right: 3px;
  top: 7px;
  height: 1px;
}

.page-about .about-fold-mark::after {
  top: 3px;
  bottom: 3px;
  left: 7px;
  width: 1px;
  transition: transform .2s ease, opacity .2s ease;
}

.page-about .about-fold-item[open] .about-fold-mark::after {
  transform: scaleY(0);
  opacity: 0;
}

.page-about .about-fold-item[open] .about-fold-head {
  color: var(--brand);
}

.page-about .about-fold-body {
  max-width: 66ch;
  padding: 0 4px 22px;
  font-size: 15.5px;
  line-height: 1.82;
  color: var(--stone);
}

.page-about .about-fold-body p {
  margin: 0 0 .9em;
}

.page-about .about-fold-body ol {
  margin: 0;
  padding-left: 1.25em;
}

.page-about .about-fold-body li {
  margin-bottom: .35em;
}

/* ---------- 反馈收束 ---------- */
.page-about .about-feedback {
  padding-bottom: 76px;
}

.page-about .about-feedback-inner {
  position: relative;
  overflow: hidden;
  padding: 26px 20px 28px;
  background: var(--mist);
  border: 1px solid rgba(16, 200, 165, .38);
}

.page-about .about-feedback-inner::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 4px;
  background: var(--live);
}

.page-about .about-feedback-text {
  margin: 16px 0 0;
  max-width: 60ch;
  font-size: 16px;
  line-height: 1.8;
  color: var(--ink-800);
}

.page-about .about-contact {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: rgba(16, 200, 165, .3);
  border: 1px solid rgba(16, 200, 165, .3);
}

.page-about .about-contact > li {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 14px;
  padding: 14px 16px;
  background: var(--mist);
}

.page-about .about-contact-key {
  flex: 0 0 auto;
  font-size: 12.5px;
  letter-spacing: .08em;
  color: var(--stone);
}

.page-about .about-contact-val {
  flex: 1 1 auto;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 15px;
  font-weight: 700;
  color: var(--ink-900);
  word-break: break-all;
}

.page-about .about-copy {
  flex: 0 0 auto;
  min-height: 40px;
}

.page-about .about-feedback-note {
  margin: 14px 0 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--stone);
}

.page-about .about-feedback-actions {
  margin-top: 22px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 悬浮快捷 ---------- */
.page-about .about-dock {
  position: fixed;
  right: 14px;
  bottom: 84px;
  z-index: 45;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.page-about .about-dock-btn {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  background: var(--ink-800);
  color: var(--brand-soft);
  border: 1px solid var(--line-dark);
  text-decoration: none;
  box-shadow: var(--shadow-1);
  transition: background-color .18s ease, color .18s ease;
}

.page-about .about-dock-btn:hover,
.page-about .about-dock-btn:focus-visible {
  background: var(--brand);
  color: var(--ink-900);
}

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

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

  .page-about .about-feedback-inner {
    padding: 34px 32px 36px;
  }

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

@media (min-width: 860px) {
  .page-about .about-origin-grid {
    grid-template-columns: 200px minmax(0, 1fr);
    gap: 56px;
    align-items: start;
  }

  .page-about .about-team-row {
    grid-template-columns: 118px minmax(0, 1fr) 74px;
    grid-template-areas:
      "name track num"
      "desc desc desc";
    gap: 10px 20px;
    padding: 18px 14px;
  }

  .page-about .about-team-num {
    text-align: right;
  }

  .page-about .about-partners-grid {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, .85fr);
    gap: 46px;
    align-items: start;
  }

  .page-about .about-tl-rail {
    display: block;
    margin: 34px 0 0;
  }

  .page-about .about-tl-rail svg {
    display: block;
    width: 100%;
    height: 24px;
  }

  .page-about .about-tl {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 16px;
    margin-top: 0;
  }

  .page-about .about-fold-head {
    font-size: 18px;
    padding: 20px 4px;
  }
}

@media (min-width: 1024px) {
  .page-about .about-masthead {
    padding-top: 34px;
    padding-bottom: 60px;
  }

  .page-about .about-feedback {
    padding-bottom: 96px;
  }

  .page-about .about-dock {
    right: 24px;
    bottom: 28px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-team-row,
  .page-about .about-team-bar,
  .page-about .about-team-desc,
  .page-about .about-tl-node,
  .page-about .about-tl-dot,
  .page-about .about-fold-mark::after,
  .page-about .about-fold-head,
  .page-about .about-dock-btn,
  .page-about .about-step {
    transition: none;
  }
}

.page-about {
  --c: transparent;
  --w: 1rem;
}