.page-about {
  --about-rail: 100%;
  --about-line: rgba(147, 183, 203, 0.28);
  color: var(--white);
}

@media (min-width: 900px) {
  .page-about {
    --about-rail: 220px;
  }
}

/* ---------- 首屏 ---------- */

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(1.75rem, 5vw, 3rem);
  margin-top: clamp(1.5rem, 4vw, 2.5rem);
}

@media (min-width: 1000px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    align-items: end;
  }
}

.page-about .about-hero h1 {
  font-family: var(--font-display);
  font-size: clamp(2.2rem, 6.2vw, 4.6rem);
  line-height: 1.08;
  letter-spacing: -0.02em;
  margin: 0.75rem 0 1.25rem;
}

.page-about .about-hero__copy .lead {
  color: var(--mist);
  font-family: var(--font-body);
  font-size: clamp(1rem, 1.5vw, 1.125rem);
  line-height: 1.85;
  max-width: 48ch;
}

.page-about .about-hero__aside {
  background: var(--ink-800);
  border: 1px solid var(--ink-700);
  border-top: 2px solid var(--gold);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.25rem 1rem;
}

.page-about .fact-row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.6rem 0;
  border-bottom: 1px dashed var(--about-line);
}

.page-about .fact-row:last-child {
  border-bottom: 0;
  padding-bottom: 0.2rem;
}

.page-about .fact-row__key {
  font-family: var(--font-display);
  font-size: 0.78rem;
  letter-spacing: 0.14em;
  color: var(--mist);
}

.page-about .fact-row__val {
  font-family: var(--font-mono);
  font-size: 0.95rem;
  color: var(--white);
  white-space: nowrap;
}

.page-about .about-hero__figure {
  margin: clamp(2rem, 5vw, 3.5rem) 0 0;
}

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

.page-about .figure figcaption {
  font-family: var(--font-body);
  font-size: 0.875rem;
  color: var(--mist);
  margin-top: 0.75rem;
}

/* ---------- 时间线 ---------- */

.page-about .tl {
  display: grid;
  gap: 2rem;
  margin-top: clamp(2rem, 5vw, 3rem);
}

@media (min-width: 900px) {
  .page-about .tl {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: clamp(2rem, 4vw, 4rem);
  }
}

.page-about .about-rail {
  display: flex;
  gap: 0.5rem;
  overflow-x: auto;
  padding-bottom: 0.5rem;
}

@media (min-width: 900px) {
  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 2rem);
    align-self: start;
    flex-direction: column;
    gap: 0.35rem;
    overflow: visible;
    padding-bottom: 0;
    border-left: 1px solid var(--ink-700);
    padding-left: 0.5rem;
  }
}

.page-about .about-rail__link {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.55rem 0.85rem;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.9rem;
  letter-spacing: 0.04em;
  color: var(--mist);
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.2s var(--ease), background 0.2s var(--ease), border-color 0.2s var(--ease);
}

.page-about .about-rail__link::before {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--ink-700);
  flex: none;
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  color: var(--white);
  background: var(--ink-800);
  border-color: var(--ink-700);
}

.page-about .about-rail__link:hover::before,
.page-about .about-rail__link:focus-visible::before {
  background: var(--cyan);
}

.page-about .tl__body {
  border-left: 1px solid var(--ink-700);
  padding-left: clamp(1.1rem, 3vw, 2.25rem);
}

.page-about .tl-node {
  position: relative;
  padding-bottom: clamp(2rem, 5vw, 3.25rem);
  scroll-margin-top: calc(var(--header-h) + 2rem);
}

.page-about .tl-node:last-child {
  padding-bottom: 0;
}

.page-about .tl-node::before {
  content: "";
  position: absolute;
  top: 0.6rem;
  left: calc(-1 * clamp(1.1rem, 3vw, 2.25rem) - 5px);
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--ink-700);
  box-shadow: 0 0 0 4px var(--ink-800);
  transition: background 0.25s var(--ease), box-shadow 0.25s var(--ease);
}

.page-about .tl-node:hover::before,
.page-about .tl-node:target::before {
  background: var(--gold);
  box-shadow: 0 0 0 4px var(--ink-800), 0 0 0 6px rgba(201, 162, 74, 0.35);
}

.page-about .tl-node__year {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1.75rem, 5vw, 3rem);
  line-height: 1;
  letter-spacing: -0.01em;
  color: var(--gold);
}

.page-about .tl-node__title {
  font-family: var(--font-display);
  font-size: clamp(1.15rem, 2.2vw, 1.5rem);
  line-height: 1.4;
  margin: 0.75rem 0 0.6rem;
}

.page-about .tl-node p {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.85;
  color: var(--mist);
  max-width: 60ch;
}

/* ---------- 日常工作 ---------- */

.page-about .work-grid {
  display: grid;
  gap: 1.25rem;
  margin-top: clamp(2rem, 5vw, 3rem);
}

@media (min-width: 720px) {
  .page-about .work-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1.5rem;
  }
}

@media (min-width: 1100px) {
  .page-about .work-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .work-item:nth-child(2),
  .page-about .work-item:nth-child(4) {
    transform: translateY(30px);
  }
}

.page-about .work-item {
  background: var(--ink-800);
  border: 1px solid var(--ink-700);
  border-top: 2px solid var(--cyan);
  border-radius: var(--radius-md);
  padding: 1.35rem 1.25rem 1.5rem;
}

.page-about .work-item__num {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.14em;
  color: var(--cyan);
}

.page-about .work-item__title {
  font-family: var(--font-display);
  font-size: 1.08rem;
  line-height: 1.45;
  margin: 0.7rem 0 0.55rem;
}

.page-about .work-item p {
  font-family: var(--font-body);
  font-size: 0.94rem;
  line-height: 1.8;
  color: var(--mist);
  margin: 0;
}

.page-about .work-item a,
.page-about .cover-copy a,
.page-about .about-next a {
  color: var(--cyan);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ---------- 团队分工 ---------- */

.page-about .team-layout {
  display: grid;
  gap: clamp(1.75rem, 4vw, 3rem);
  margin-top: clamp(2rem, 5vw, 3rem);
}

@media (min-width: 1000px) {
  .page-about .team-layout {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    align-items: start;
  }
}

.page-about .team-layout .figure {
  margin: 0;
}

.page-about .team-list {
  display: grid;
  gap: 1rem;
}

@media (min-width: 640px) {
  .page-about .team-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1.25rem;
  }
}

.page-about .team-card {
  background: var(--ink-900);
  border: 1px solid var(--ink-700);
  border-radius: var(--radius-md);
  padding: 1.3rem 1.2rem 1.4rem;
}

.page-about .team-card__count {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1.9rem, 4vw, 2.5rem);
  line-height: 1;
  color: var(--white);
}

.page-about .team-card__count::after {
  content: " 人";
  font-family: var(--font-display);
  font-size: 0.8rem;
  letter-spacing: 0.14em;
  color: var(--mist);
}

.page-about .team-card__title {
  font-family: var(--font-display);
  font-size: 1.02rem;
  margin: 0.8rem 0 0.5rem;
  color: var(--cyan);
}

.page-about .team-card p {
  font-family: var(--font-body);
  font-size: 0.92rem;
  line-height: 1.8;
  color: var(--mist);
  margin: 0;
}

/* ---------- 服务覆盖 ---------- */

.page-about .cover-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1.25rem;
  margin-top: clamp(2rem, 5vw, 3rem);
}

@media (min-width: 900px) {
  .page-about .cover-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 1.75rem;
  }
}

.page-about .cover-stat {
  border-left: 2px solid var(--cyan);
  padding: 0.35rem 0 0.35rem 0.95rem;
}

.page-about .cover-stat:nth-child(even) {
  border-left-color: var(--gold);
}

.page-about .cover-stat__value {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1.6rem, 4vw, 2.35rem);
  line-height: 1.1;
  color: var(--white);
}

.page-about .cover-stat__label {
  display: block;
  margin-top: 0.4rem;
  font-family: var(--font-display);
  font-size: 0.8rem;
  letter-spacing: 0.1em;
  color: var(--mist);
}

.page-about .cover-copy {
  margin-top: clamp(1.75rem, 4vw, 2.5rem);
  max-width: 72ch;
}

.page-about .cover-copy p {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.9;
  color: var(--mist);
}

.page-about .cover-copy p + p {
  margin-top: 0.9rem;
}

/* ---------- 合作方 ---------- */

.page-about .partner-grid {
  display: grid;
  gap: 1.5rem;
  margin-top: clamp(2rem, 5vw, 3rem);
}

@media (min-width: 900px) {
  .page-about .partner-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 2rem;
  }
}

.page-about .partner-card {
  border: 1px solid var(--ink-700);
  border-radius: var(--radius-md);
  background: var(--ink-800);
  padding: 1.5rem 1.35rem 1.6rem;
}

.page-about .partner-card__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding-bottom: 0.85rem;
  border-bottom: 1px solid var(--ink-700);
}

.page-about .partner-card__title {
  font-family: var(--font-display);
  font-size: 1.2rem;
  margin: 0;
}

.page-about .partner-card__desc {
  font-family: var(--font-body);
  font-size: 0.94rem;
  line-height: 1.8;
  color: var(--mist);
  margin: 1rem 0 1.1rem;
}

.page-about .partner-tags {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.5rem;
}

.page-about .partner-tag {
  border: 1px solid var(--ink-700);
  border-radius: var(--radius-sm);
  padding: 0.6rem 0.75rem;
  background: var(--ink-900);
  cursor: default;
  transition: border-color 0.2s var(--ease), background 0.2s var(--ease);
}

.page-about .partner-tag:hover,
.page-about .partner-tag:focus-visible {
  border-color: var(--cyan);
  background: var(--ink-deep);
  outline: none;
}

.page-about .partner-tag__name {
  display: block;
  font-family: var(--font-display);
  font-size: 0.9rem;
  color: var(--white);
}

.page-about .partner-tag__note {
  display: block;
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  font-family: var(--font-body);
  font-size: 0.86rem;
  line-height: 1.75;
  color: var(--mist);
  transition: max-height 0.24s var(--ease), opacity 0.24s var(--ease), margin-top 0.24s var(--ease);
}

.page-about .partner-tag:hover .partner-tag__note,
.page-about .partner-tag:focus-visible .partner-tag__note,
.page-about .partner-tag:focus-within .partner-tag__note {
  max-height: 6rem;
  opacity: 1;
  margin-top: 0.4rem;
}

@media (max-width: 719px) {
  .page-about .partner-tag__note {
    max-height: none;
    opacity: 1;
    margin-top: 0.4rem;
  }
}

/* ---------- 更新节奏 ---------- */

.page-about .cadence-layout {
  display: grid;
  gap: clamp(1.75rem, 4vw, 3rem);
  margin-top: clamp(2rem, 5vw, 3rem);
}

@media (min-width: 960px) {
  .page-about .cadence-layout {
    grid-template-columns: minmax(0, 6fr) minmax(0, 5fr);
    align-items: start;
  }
}

.page-about .cadence-layout .figure {
  margin: 0;
}

.page-about .cadence-row {
  display: flex;
  gap: 1rem;
  padding: 1.15rem 0;
  border-bottom: 1px solid var(--ink-700);
}

.page-about .cadence-row:first-child {
  padding-top: 0;
}

.page-about .cadence-row__num {
  flex: none;
  min-width: 3.6rem;
  font-family: var(--font-mono);
  font-size: clamp(1.35rem, 3vw, 1.8rem);
  line-height: 1.2;
  color: var(--cyan);
}

.page-about .cadence-row__title {
  font-family: var(--font-display);
  font-size: 1.05rem;
  margin: 0 0 0.45rem;
}

.page-about .cadence-row p {
  font-family: var(--font-body);
  font-size: 0.94rem;
  line-height: 1.8;
  color: var(--mist);
  margin: 0;
}

.page-about .cadence-plaque {
  margin-top: 1.75rem;
}

/* ---------- 全程折叠 ---------- */

.page-about .expand-list {
  margin-top: clamp(2rem, 5vw, 3rem);
}

.page-about .expand__btn {
  display: grid;
  grid-template-columns: 5.5rem minmax(0, 1fr) auto;
  align-items: center;
  gap: 0.9rem;
  width: 100%;
  text-align: left;
}

.page-about .expand__code {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--gold);
  letter-spacing: 0.04em;
}

.page-about .expand__title {
  font-family: var(--font-display);
  font-size: 1rem;
  line-height: 1.5;
}

.page-about .expand__panel-inner p {
  font-family: var(--font-body);
  font-size: 0.96rem;
  line-height: 1.85;
  color: var(--mist);
  margin: 0;
}

/* ---------- 收尾引导 ---------- */

.page-about .about-next {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.85;
  color: var(--white);
  margin: 0;
  max-width: 76ch;
}

/* ---------- 动效降级 ---------- */

@media (prefers-reduced-motion: reduce) {
  .page-about .work-item,
  .page-about .about-rail__link,
  .page-about .partner-tag,
  .page-about .partner-tag__note,
  .page-about .tl-node::before {
    transition: none;
    transform: none;
  }
}